Tropical Fruits, 2ed

CROP PRODUCTION SCIENCE IN HORTICULTURE SERIES

Series Editor: Jeff Atherton, Professor of Tropical Horticulture,

University of the West Indies, Barbados

This series examines economically important horticultural crops selected from the

major production systems in temperate, subtropical and tropical climatic areas.

Systems represented range from open ﬁ eld and plantation sites to protected plastic

and glass houses, growing rooms and laboratories. Emphasis is placed on the scientiﬁ c

principles underlying crop production practices rather than on providing empirical

recipes for uncritical acceptance. Scientiﬁ c understanding provides the key to both

reasoned choice of practice and the solution of future problems.

Students and staff at universities and colleges throughout the world involved in

courses in horticulture, as well as in agriculture, plant science, food science and

applied biology at degree, diploma or certiﬁ cate level will welcome this series as a

succinct and readable source of information. The books will also be invaluable to

progressive growers, advisers and end-product users requiring an authoritative, but

brief, scientiﬁ c introduction to particular crops or systems. Keen gardeners wishing

to understand the scientiﬁ c basis of recommended practices will also ﬁ nd the series

very useful.

The authors are all internationally renowned experts with extensive experience

of their subjects. Each volume follows a common format, covering all aspects of

production, from background physiology and breeding to propagation and planting,

through husbandry and crop protection to harvesting, handling and storage. Selective

references are included to direct the reader to further information on speciﬁ c topics.

Titles available:

1. Ornamental Bulbs, Corms and Tubers A.R. Rees

2. Citrus F.S. Davies and L.G. Albrigo

3. Onions and Other Vegetable Alliums J.L. Brewster

4. Ornamental Bedding Plants A.M. Armitage

5. Bananas and Plantains J.C. Robinson

6. Cucurbits R.W. Robinson and D.S. Decker-Walters

7. Tropical Fruits H.Y. Nakasone and R.E. Paull

8. Coffee, Cocoa and Tea K.C. Willson

9. Lettuce, Endive and Chicory E.J. Ryder

10. Carrots and Related Vegetable Umbelliferae V.E. Rubatzky, C.F. Quiros and

P.W. Simon

11. Strawberries J.F. Hancock

12. Peppers: Vegetable and Spice Capsicums P.W. Bosland and E.J. Votava

13. Tomatoes E. Heuvelink

14. Vegetable Brassicas and Related Crucifers G. Dixon

15. Onions and Other Vegetable Alliums, 2nd Edition J.L. Brewster

16. Grapes G.L. Creasy and L.L. Creasy

17. Tropical Root and Tuber Crops: Cassava, Sweet Potato, Yams and

Aroids V. Lebot

18. Olives I. Therios

19. Bananas and Plantains, 2nd Edition J.C. Robinson and V. Galán Saúco

20. Tropical Fruits, 2nd Edition, Volume 1 R.E. Paull and O. Duarte

This page intentionally left blank

T F,

2 E, V 1

Robert E. Paull

Professor of Plant Physiology

College of Tropical Agriculture and Human Resources

University of Hawaii at Manoa

Honolulu, HI, USA

and

Odilo Duarte

Professor and Lead Scientist in Agribusiness

CENTRUM Católica Business School

Pontiﬁ cia Universidad Católica del Perú

Lima, Perú

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publication may be reproduced in any form or by any means,

electronically, mechanically, by photocopying, recording or otherwise,

without the prior permission of the copyright owners.

A catalogue record for this book is available from the British Library,

London, UK.

Library of Congress Cataloguing-in-Publication Data

Paull, Robert E.

Tropical fruits / Robert E. Paull and Odilo Duarte. -- 2nd ed.

p. cm. -- (Crop production science in horticulture series ; no. 20)

Includes bibliographical references and index.

ISBN 978-1-84593-672-3 (alk. paper)

1. Tropical fruit. I. Duarte, Odilo. II. C.A.B. International. III. Title. IV. Series: Crop

production science in horticulture ; 20.

SB359.P38 2011

634′.6--dc22

2010016776

ISBN: 978 1 84593 672 3

Commissioning editor: Sarah Hulbert

Production editor: Shankari Wilford

Typeset by Columns Design Ltd, Reading, UK.

Printed and bound in the UK by MPG Books Group.

CONTENTS

PREFACE vii

INTRODUCTION 1

THE TROPICS, ITS SOILS AND HORTICULTURE 11

CULTIVATION 33

TREE MANAGEMENT 62

POSTHARVEST TECHNOLOGY 101

ANNONAS: CHERIMOYA, ATEMOYA AND SWEETSOP 123

AVOCADO 153

BANANA AND PLANTAIN 185

LITCHI AND LONGAN 221

vi Contents

MANGO 252

PAPAYA 291

PINEAPPLE 327

REFERENCES 366

INDEX 393

vii

PREFACE

The monoaxial banana, pineapple and papaya and polyaxial mango are

the most well-known tropical fruits worldwide. Avocado is better known for

production in subtropical areas, but considerably more production occurs in

the tropical zone. Banana, pineapple and avocado are extensively grown by

large companies. Banana, along with plantain, is the largest fruit crop in the

tropics, with only a small fraction entering international commerce. Many

other tropical fruits, already well known in the tropics, are now appearing in

larger temperate city markets.

The ﬁ rst edition of this book was started by Dr Henry Nakasone after he

retired from the University of Hawaii at Manoa in 1981. His work on the book

was prolonged because of his extensive volunteer and consulting activities

from his retirement to 6 months before his death in 1995. The extensive

research carried out by Henry in preparing some draft chapters laid the

foundation for the 1998 ﬁ rst edition. Henry understood the need for a book

that melded equally the genetics, physiology and cultural practices with

postharvest handling of each fruit crop as an interrelated whole.

This second edition has been completely revised and new chapters added.

A colleague, Dr Odilo Duarte, formerly Professor from Escuela Agrícola

Panamericana – El Zamorano, Honduras, and now Professor and Lead

Scientist in Agribusiness, CENTRUM Católica Business School, Pontificia

Universidad Católica del Perú, Lima, Perú, joined me in this revision. It was

decided to make this a general tropical fruit production textbook and only

cover the major tropical crops in Volume 1. The other tropical fruits have been

moved to Volume 2, which should appear next year.

The ﬁ rst ﬁ ve chapters deal with the general aspects of the tropical climate,

fruit production techniques, tree management and postharvest handling.

Subsequent chapters deal with the principal tropical fruit crops that are

common in temperate city markets. The information in each fruit chapter

deals with taxonomy, varieties, propagation and orchard management, biotic

and abiotic problems, variety development and postharvest handling. The

information contained should be of use to all readers and students interested

in an introductory text on tropical fruit production.

viii Preface

Many have contributed to the ﬁ rst edition and to this edition. Encourage-

ment and help to Henry in this passion came from many, and they were

acknowledged in the ﬁ rst edition. Others must be mentioned who provided

help and encouragement since the ﬁ rst edition, including Skip Bittenbender,

Victor Galán Saúco, Ying Kwok Chan, George Wilson, Ken Rohrbach, Duane

Bartholomew, Francis Zee, Ken Love and Chun Ruey Yen. Their numerous

comments and suggestions have been incorporated in most cases. All errors

and omissions are our responsibility. The illustrations of each crop were done

by Susan Monden, and her perseverance and skill were greatly appreciated.

Thanks are also due to the Commissioning Editor, Sarah Hulbert, for her

assistance and patience during the book’s development.

We would greatly appreciate receiving all comments and suggestions on this

text. We can be reached at the addresses given on the title page or via e-mail at

paull@hawaii.edu or odiloduarte@yahoo.com

In closing, we both acknowledge the continued support, assistance and

love of our wives, Nancy and Carla, and our children, which enabled us to

complete this undertaking.

Robert E. Paull

Honolulu

USA

2010

Odilo Duarte

Lima

Perú

2010

(R.E. Paull and O. Duarte)

INTRODUCTION

The tropics, with its warm climate and little temperature variation, occupies

approximately 40% of the earth’s land surface. The region also has half the

world’s population. The majority of the world’s biodiversity is also found in

the tropics, biodiversity being the total of all living organisms on earth. These

endemic animals and plants are adapted to the diverse tropical environments,

which range from wet tropical rainforests to deserts and snow-covered, high

mountains.

The tropics can be divided into three major zones. The zone most

recognized is that with year-round rainfall and lies on the equator (Amazon,

Central America, Central Africa, Indonesia, New Guinea) and is ~8% of

the world’s land surface. As one moves away from the equator, the rainfall

becomes more seasonal, and this zone occupies 16% of the land area (Central

America, north and south Amazon, West Africa, India, South-east Asia,

northern Australia). The last is the dry tropics, which makes up 16% of the

land area and ranges from deserts to large areas with long dry seasons of 9

months or more. Examples would be the Sahara, Bolivian El Chaco lowlands,

central India and northern central Australia.

About half of the plant families are tropical, and the tropical region

contains 15 of the 25 world biodiversity ‘hot spots’ (Crane and Lidgard, 1989;

Meyer et al., 2000). The ‘hot spots’ are regarded as centres for agricultural

origins, and it is thought that crop domestication took place in or near these

‘hot spots’. This domestication reﬂ ects the role of hunter–gatherers and early

farmers, and their dependence on these crops for their daily subsistence. The

abundance of species with di erent life cycles, adaptations and useful products

in these ‘hot spots’ would facilitate their selection by hunter–gatherers and

early farmers. Examples of these centres include half of the southern part

of Mexico and the northern half of Central America, Ecuador, western and

central Brazil, the Indo-Burma region, South-east Asia, the Indonesian and

Philippine archipelagos, the East Melanesian Islands and Paciﬁ c Micronesia.

2 Chapter 1

TROPICAL FRUITS

Most botanical families have at least one species of tropical fruit (Table 1.1).

In tropical America, more than 1000 fruit species are described, though only

100 are found in local markets. Asia has about 500 tropical fruit species, the

Indian subcontinent about 300, with about 1200 in Africa. Of these fruits

only a few are found in local markets and fewer are exported. Ninety per

cent of the export market is made up of citrus, banana and plantain, mango

and pineapples (Table 1.2). A further 5% is made up of papaya, avocado

and dates. The remainder is made up of more than 20 species, ranging from

breadfruit and litchi to mangosteen, passion fruit and coconut. More than

90–95% of tropical fruits are not exported from the producing country but

are consumed locally.

The most common tropical fruits in trade come from three major areas:

Central and South America (papaya, avocado, pineapple, guava), Asia

(most citrus fruits, litchi), and South and South-east Asia (banana, mango,

mangosteen, durian) (Gepts, 2008). Only one important tropical fruit is native

to Africa and that is the date, though the continent has many other tropical

fruits. Fruit species were selected by man and distributed widely throughout

the world, based upon various factors, which included the crop’s adaptability

to di erent environments, the fruit’s seed storage life, ease of plant propagation

(seed, cuttings, plants), the size and shape of the plant, a multiplicity of uses

other than as a fresh fruit (cloth, medicinal, wood) and having an agreeable

taste. Many tropical seeds are recalcitrant and cannot be dried and must be

transported as cuttings or plants to be introduced to new areas.

As people migrated, often the crops with which they were familiar were

taken along. The spread to areas surrounding that of their origin probably

began early. For example, the mango, a native of the Indo-Burma region,

had spread to all of South-east Asia by the end of the fourth century .

Arabs traders in the Indian Ocean probably took mangoes to the east coast

of Africa around 700 . The orange was also moved, most likely by Arab

traders, to the Mediterranean and southern Europe. Opportunities probably

also existed to move some tropical fruits (e.g. pineapple) around the warmer

areas of Central and South America. The European discovery of America led

to a rapid exchange of tropical fruit crops between the Old and New Worlds.

Bananas were carried to Santo Domingo from the Canary Islands in 1516. The

Portuguese spread tropical fruits from their colony in Brazil around the Cape

of Good Hope to Goa in India, Malacca in Malaysia, China and Japan. The

Spanish had a regular galleon service from Mexico to the Philippines between

1565 and 1815. The Dutch, British and French ships also spread tropical

fruits around the globe.

Introduction 3

Table 1.1. Taxonomy and primary centre of diversity and probable centre of origin of the major tropical fruits (Gepts, 2008).

Order Family (subfamily) Crop(s), taxa Centre of origin

Magnoliid

complex

Laurales Lauraceae

Avocado, Persea americana

Tropical Central America

Magnoliales Annonaceae

Annona spp., cherimoya, ilama, soursop, sweetsop,

atemoya; Rollinia pulchrinervis, biriba

Tropical South America

Monocots Arecales

Coconut, Cocos nucifera

South-east Asia

Date, Phoenix dactylifera

N. Africa, Middle East

Poales Bromeliaceae

Pineapple, Ananas comosus

South America

Zingiberales Musaceae

Banana and plantain, Musa spp.

South-east Asia

Eudicots Caryophyllales Cactaceae Pitaya Tropical America

Oxalidales Oxalidaceae

Carambola, Averrhoa carambola

South-east Asia

Malpighiales Malpighiaceae

Barbados cherry, Malpighia glabra

West Indies, South America

Clusiaceae (Guttiferae)

Mangosteen, Garcinia mangostana

South-east Asia

Passiﬂ oraceae

Passion fruit, Passiflora spp.

Tropical America

Rosales Moraceae Breadfruit, chempedak, jackfruit, etc.,

Artocarpus spp.

Polynesia

Myrtales Myrtaceae

Surinam cherry, Eugenia spp.

Tropical America

Jaboticaba, Myrciaria cauliflora

Brazil

Guava, Psidium guajava

Tropical America

Brassicales Caricaceae

Papaya, Carica papaya

Central America

Malvales Malvaceae

Durian, Durio zibethinus

South-east Asia

Sapindales Sapindaceae

Longan, Dimocarpus longan; litchi, Litchi

chinensis; and rambutan, Nephelium lappaceum

South-east Asia

Rutaceae

Citrus, Citrus spp.

South-east Asia

Anacardiaceae

Cashew, Anacardium occidentale

Tropical America

Mango, Mangifera indica

India, South-east Asia

Hog plum, mombins, Spondias spp.

Tropics

Ericales Sapotaceae

Caimito, Chrysophyllum cainito

South America

Sapodilla, Manilkara zapota

Central America

Mamey sapote, Pouteria sapota

Mexico, Central America

4 Chapter 1

TROPICAL FRUIT CHARACTERISTICS

Tropical fruits are harvested from woody plants (avocado, mango, orange)

but also from herbaceous plants (banana, papaya) and vines (passion fruit).

The evolution of fruit in the early Tertiary period was a major advance that

Table 1.2. World production and acreage of major tropical fruits in 2007, from FAO

Statistics Division (FAO, 2009).

Fruit

Production

(1000 of t)

Acreage

harvested

(1000 × ha) Important producing countries

Avocado 3,569 407 Mexico, United States,

Dominican Republic, Brazil,

Colombia, Chile, South Africa,

Indonesia, Israel, Spain

Banana Dessert 85,856 5,109 Burundi, Nigeria, Costa Rica,

Mexico, Colombia, Ecuador,

Brazil, India, Indonesia,

Philippines, Papua New

Guinea, Spain, Central America

Plantain 33,925 5,375 Colombia, Ecuador, Peru,

Venezuela, Ivory Coast,

Cameroon, Sri Lanka,

Myanmar

Citrus Oranges 7,104 1,071 Brazil, United States, India,

Mexico, Spain, China, Italy,

Egypt, Pakistan, Greece, South

Africa

Tangerines

and

Mandarins

27,865 2,052 Brazil, United States, India,

Mexico, Spain, China, Italy,

Egypt, Pakistan, Greece, South

Africa, Japan

Coconut 61,504 11,106 Indonesia, Philippines, India,

Sri Lanka, Brazil, Thailand,

Mexico, Vietnam, Malaysia,

Papua New Guinea

Mango 33,446 4,610 India, Pakistan, Indonesia,

Philippines, Thailand, Mexico,

Haiti, Brazil, Nigeria

Papaya 7,208 378 Nigeria, Mexico, Brazil, China,

India, Indonesia, Thailand, Sri

Lanka

Pineapple 20,911 2,378 Philippines, Thailand, India,

Indonesia, China, Brazil, United

States, Mexico, Nigeria, Vietnam

Introduction 5

increased the e ciency of angiosperm seed dispersal. Climate change,

radiation of birds and animals, and changes in plant community habitats are

all potential evolutionary forces that led to the appearance of a range of fruit

types. The ﬂ eshy fruits, with their mutually beneﬁ cial interaction of providing

nutrition to animals and improving seed dispersal, have arisen independently

in di erent families, have disappeared and reappeared, are not evolutionarily

conserved, and show no clear association with phylogeny. The fossil and

morphological evidence indicates that multiple fruit types have evolved

directly from a dry follicle-bearing ancestor (Fig. 1.1).

The follicle is seen as the archetypical progenitor fruit, with a single

fused carpel that splits along a single seam (dehiscent zone). The fused carpel

appeared about 97 million years ago (Mya), in the middle Cretaceous. The

abscission (separation) zones are found much earlier in the fossil record

(400 Mya) in early vascular plants. In fruit, the biochemical processes in the

dehiscence zones and during ripening are thought to have co-opted systems

that evolved for the abscission of sporangia, leaves, petals and stamens. The

fruits that are consumed have soft and juicy arils (rambutan, litchi, longan),

pedicel (cashew), ﬂ oral and accessory tissue (pineapple, annonas), mesocarp

Fig. 1.1. Types and structures of tropical fruits and their evolutionary development

from dehiscent and non-dehiscent dry fruits (redrawn from ﬁ gures in Nakasone and

Paull, 1998).

6 Chapter 1

(papaya, avocado) and endocarp (citrus). A few species are in the magnoliid

complex (annonas, avocado) and monocots (banana, coconut, pineapple);

the most important species are all eudicots. The ﬂ oral parts of the magnoliid

complex occur in whorls of three (trimerous); the pollen has one pore and

they usually have branching-veined leaves and are regarded as basal or more

‘primitive’ angiosperms.

Tropical fruits, in most cases, are sold fresh, and o -grade fruit is

processed. The exception to this would be coconut, which is grown principally

for other products (copra, oil, coir) with a small acreage, often of special

varieties, that are grown for fresh consumption. Cashew is grown mainly

for its nut, with the ﬂ eshy pedicel being eaten fresh, processed and made into

juice. Most tropical fruits are highly perishable, and signiﬁ cant development

has taken place to process selected fruits into dried products, juices and purees.

Bananas such as plantains are also often used as a starch staple in Africa, Asia

and Latin America and not as a dessert fruit.

NUTRITIONAL VALUE

Nutrient contents of tropical fruits found in food composition tables are used

for nutritional assessment, research linking diet to health, nutritional policy,

food labelling, and consumer education. Accurate data are needed in order to

predict dietary energy intake and undernourishment. For tropical fruit, this

is important, as they are often regarded as signiﬁ cant sources of minerals,

vitamins and carbohydrates (Favier et al., 1993).

Natural variation occurs in the nutrient content of fruits. This variability

is due to soil and climatic conditions, variety grown, the stage of maturity at

harvest and physiological state when eaten. Traditionally, food composition

tables for most foods are presented as mean values, ignoring the natural

biological variability. It is probably more useful to know the range of values

found and the standard error or deviation.

Most food composition tables present data as nutrient values per 100 g of

edible food. Tropical fruits have low to moderate energy content and provide

about 200 to 300 kJ (FAO, 2003). Some tropical fruits, such as bananas (380

kJ), avocado (572 kJ) and durians (536 kJ), are higher and others less energy-

dense, such as the carambola (121 kJ). The protein content of most fruits,

including tropical fruits, is low (<1 g/100 g), though avocado (1.8 g) and

durians (2.6 g) are higher. Fat contents are also low, except for avocado (14.2 g)

and durians (2–5 g). The carbohydrate content is presented as monosaccharide

equivalents with ﬁ bre excluded, and contents normally range from 10 to 15 g,

which is the range that most consumers regard as sweet. Higher carbohydrate

contents are found in bananas (~20 g), atemoya (~21 g) and durians (~26 g).

Dietary ﬁ bre is reported to range from 1 to 2 g in tropical fruits, though di erent

analytical methods are used that give di erent values in the same fruit.

Introduction 7

Tropical fruits are low to moderate sources of macronutrients and good

sources of micronutrients. For example, while most fruits have 10–20 mg of

calcium, mango only has ~1.2 mg. Iron ranges from 0.2 to 0.4 mg. Banana

and durian are good sources of potassium, having 100–200 mg. Some fruits

are good sources of folate, and most are high sources of vitamin C (>20 mg).

The beta-carotene in fruit varies widely, depending upon the content of the

di erent carotenes present. The di erent varieties of mangoes can vary in beta-

carotene from 350 to 13,000 mcg. Other components present in tropical fruits

include antioxidants and other phytochemicals that have potential health-

promoting e ects, with various claims being made.

Nutrient and health claims are frequently made for tropical fruits. Codex

Alimentarius (2001) has set standards for health-claim labelling. Using these

standards, some nutrient claims can be made for tropical fruit (Table 1.3). For

example, for a product to be low in fat it must have less than 3 g/100 g; for a

tropical fruit to be a ‘source’ of a particular nutrient it must contain 15% and

a ‘high source’ 30% of the Codex Alimentarius (2001) reference nutrient value.

SIGNIFICANT TRENDS – PRODUCTION AND MARKETING

The production and world trade in fresh tropical fruits is expected to expand

(Sarris, 2003). Most of the production occurs in developing countries (98%),

while developed countries are the major importers (80%). Citrus and bananas

are traded worldwide, followed by mango, pineapple, papaya and avocado.

Table 1.3. Potential nutrient claims that can be made for fresh tropical fruits using

standards from Codex Alimentarius (2001).

Nutrient claim

Fruit Energy Fat Vitamin A Folate Vitamin C

Avocado Source Source

Banana Low Source

Carambola Low Low High

Durian Low High

Guava Low Low High

Lime Low Low High

Litchi Low High High

Longan Low Source High

Mango Low High Source High

Papaya Low Low Source Source High

Passion fruit Low High

Pineapple Low High

Rambutan Low High

8 Chapter 1

Litchi, durian, rambutan, guava and passion fruit are produced and traded in

smaller volumes, with their market shares expanding rapidly in recent years.

The projections made by the FAO assume normal weather patterns and

the continuation of past trends in area planted, yield, income growth and

population for mango, pineapple, papaya and avocado (Table 1.2). World

production is expected to reach 62 million tonnes by 2010, an increase of

15.4 million tonnes over the 1998–2000 period, with developing countries

continuing to account for 98% of the global production. This is a compounded

growth rate of 2.6% per year. The Asia and Paciﬁ c region accounts for 56%

of production, followed by Latin America and the Caribbean (32%) and Africa

(11%). The production increase has come from additional planted acreage

intended for export. The growth has occurred mainly in Latin America and

the Caribbean region, with their more accessible trade route to the major

importing regions, the United States and Europe.

Demand for fresh tropical fruits has increased and imports are at about

4.3 million tonnes for mango, pineapple, papaya and avocado, with 87%

going to developed country markets. Europe is the world’s largest import

market, followed by the United States, accounting for 70% of import demand.

In Europe, France is a major importer, and the Netherlands is the major trans-

shipment point.

TROPICAL FRUIT AND CONSUMERS

In most markets, consumers are demanding higher quality. This quality is

no longer judged solely by size and appearance; aroma, ﬂ avour and nutrient

value are now increasing in importance. This can be seen in the larger

range of commodities on the retail shelves, the number of varieties of each

commodity now o ered, and reduction in seasonality of supply in developing

country markets. The traditional term, quality, implies excellence or suitability

for use and means di erent things to di erent groups. Suitability for use

includes freedom from microbial and chemical contaminants. Understanding

of consumer behaviour is related to how it will be accepted in the marketplace

(Sabbe et al., 2009).

Consumer satisfaction is related to their view as to what constitutes

quality, and this varies widely in di erent markets and is decided by familiarity,

economic status and marketing. For many minor tropical fruits, familiarity

in many temperate markets is a major limitation to expanding the market for

tropical fruits, coupled to a consumer willingness to try new fruits (Fig. 1.2).

INTERNATIONAL FORUMS

Numerous national and international groups are dedicated to speciﬁ c

tropical fruits or groups of closely related fruits. The International Society

Introduction 9

of Horticultural Science (ISHS) has established a Commission of Tropical

and Subtropical Horticulture, with working groups in speciﬁ c tropical and

subtropical fruits. The various working groups meet at regular intervals,

and meeting times and places are posted on the ISHS web site (http://www.

ishs.org/calendar/). The calendar posted at this site is the most extensive

that deals with horticulture conferences. The International Tropical Fruit

Network (TFNet) (http://www.itfnet.org/) is an excellent source of tropical

fruit knowledge. TFNet is an independent global network that serves as a

depository of tropical fruit production, postharvest, processing, marketing

and consumption information. For Latin America, an InterAmerican Society

of Tropical Horticulture (formerly Tropical Region of the American Society

of Horticultural Science) was active until 2006. Annual meetings were

held in di erent Latin American countries. Their web site is at (http://www.

ashs.org/isth/index.html) (accessed 19 January 2010), and this site lists the

many volumes published from 1951 to 2004, which are available in some

libraries and were abstracted in Horticulture Abstracts until 1998, and are now

available by subscription through CAB Direct (http://www.cabdirect.org/).

TROPICAL HORTICULTURE

Tropical agriculture, including fruit production, has a number of limitations.

In the next chapter we will consider the constraints associated with

Fig. 1.2. European consumers’ knowledge of different fresh tropical fruits (redrawn

from Sabbe et al., 2009).

10 Chapter 1

temperature, rainfall amount and distribution, evapotranspiration and soil

moisture. These climate factors have had, and continue to have, a signiﬁ cant

impact on abiotic and biotic factors that a ect fruit production, which will be

discussed in the individual fruit chapters.

Frequently tropical soils are highly leached and acid, with aluminium

toxicity occurring. Nitrogen levels are frequently low, due to high rainfall. The

continual high temperature in the tropics means that organic matter turnover

is high, compounded by low nitrogen availability and poor soil structure.

Leached soils are high in iron and low in phosphorus, and show micronutrient

deﬁ ciencies (Zn, Mn, S).

Pests and diseases are more proliﬁ c in the tropics, with year-round

development in the absence of a cold winter (no frost, snow or ice) to reduce

inoculum and pest levels. This biotic stress carries over to the postharvest stage

and contributes to high postharvest losses. Integrated pest management (IPM)

is now being widely applied in the tropics, where it can be successful. Ongoing

research will lead to wider application by reducing pest populations below

levels that cause economic injury.

FURTHER READING

Centeno, G. (2005) El mercado de las frutas tropicales exóticas en la Unión Europea.

CIMS, Alajuela, Costa Rica.

Chandler, W.H. (1958) Evergreen Orchards. Lea and Febiger. Philadelphia, Pennsyl vania.

Coronel, R.E. (1983) Promising Fruits of the Philippines. College, Laguna, Philippines,

College of Agriculture, University of the Philippines at Los Banos.

FAO (2003) Tropical fruits – their nutrient values, biodiversity and contribution to

health and nutrition. Intergovernmental group on bananas and tropical fruits,

third session, ftp.fao.org/unfao/bodies/ccp/ba-tf/04/j0715e.pdf (accessed 12

November 2009).

Gepts, P. (2008) Tropical environments, biodiversity, and the origin of crops. In: Moore, P.

and Ming, R. (eds) Genomics of Tropical Crop Plants. Springer, New York, pp. 1–20.

Meyer, N., Mittermeier, R.A., Mittermeier, C.G., da Fonseca, G.A.B. and Kent, J. (2000)

Biodiversity hotspots for conservation priorities. Nature 403, 853–858.

Norman, M.J.T., Pearson, C.J. and Searle, P.G.E. (1995) The Ecology of Tropical Food Crops.

Cambridge University Press, Cambridge, UK.

Popenoe, W. (1974) Manual of Tropical and Subtropical Fruits. Hafner Press, New York.

Facsimile of the original 1920 edition.

Sabbe, S., Verbeke, W. and Van Damme, P. (2009) Familiarity and purchasing intention

of Belgian consumers for fresh and processed products. British Food Journal 110,

805–818.

Sarris, A. (2003) Medium-term prospects for agricultural commodities – projections to

the year 2010. Food and Agriculture Organization of the United Nations, Rome

http://www.fao.org/docrep/006/y5143e/y5143e00.htm#Contents (accessed 24

October 2009).

(R.E. Paull and O. Duarte)

THE TROPICS, ITS SOILS AND

HORTICULTURE

INTRODUCTION

Climate is deﬁ ned as the general temperature and atmospheric conditions of an

area over an extended period of time. Atmospheric conditions include rainfall,

humidity, sunshine, wind and other factors. Climates are subject to modiﬁ cation

by various factors, such as latitude, elevation and whether or not the land

mass is continental, coastal or oceanic, direction of wind and ocean currents,

proximity to large bodies of water and mountain ranges, and cloudiness.

The tropical region is a belt around the earth between the Tropic of

Cancer at 23° 30′ latitude north of the equator and the Tropic of Capricorn

23° 30′ latitude south of the equator (Fig. 2.1). The term ‘tropics’ has its

origins in astronomy and comes from the Greek meaning ‘a turning’. In

astronomy, it deﬁ nes the farthest southern- and northernmost latitudes where

the sun shines overhead. The Tropics of Cancer and Capricorn are rather rigid

boundaries and do not take into consideration the presence of areas that do

not meet the various climatic characteristics generally established to describe

the tropics. Some climatologists have extended the region to 30° N and S of

the equator, based upon surface temperatures and precipitation, or use the

18°C isotherm of the coolest month (Fig. 2.1). This increases the land mass

in the tropics substantially, from ~40% to ~50%, especially on the continents

of Africa, China, South America and India, and would include approximately

two-thirds of Australia’s land mass.

CHARACTERISTICS OF THE TROPICS

The tropical zone is generally described as possessing the following character-

istics:

1. An equable warm temperature throughout the year, having no cold season

at lower elevations. The average annual temperature of the true tropics is

12 Chapter 2

Tropic of Cancer

Equator

Tropic of Capricorn

150 120 90 60 30 0 30 60 90 120 150 180

Fig. 2.1. Distribution of tropical and subtropical regions of the world and the position of the 18°C sea-level isotherm for the

coolest month as the boundary of the tropics. The white area indicates where frost can occur; the vertical hatching indicates the

subtropical areas, while the mottled areas are regarded as tropical.

The Tropics, its Soils and Horticulture 13

generally greater than 25°C, with no month having an average less than

18°C. Others have described the tropics as areas with a mean temperature of

not lower than 21°C and where the mean annual range of temperature equals

the daily range of temperature. The latter boundary is very much inﬂ uenced

by continentality. Another boundary is the isotherm where the mean sea-level

temperature in the coldest months is not below 18°C; though it can include

certain errors, these are relatively small on a world scale and reliable data are

available for its computation (Fig. 2.1). In the tropics, diurnal temperature

variation is greater than the seasonal change.

2. Rainfall is usually abundant, seldom less than the semi-arid 750 mm to as

high as 4300 mm, indicating considerable variation (Fig. 2.2). The heaviest

rainfall occurs near the equator. Seasonality in rainfall increases with distance

from the equator. Where rainfall is marginal for agriculture, its variability takes

on greater signiﬁ cance.

3. Photoperiod varies little throughout the year; at the equator day length is

about 12 h (Table 2.1).

4. The position of the sun is more directly overhead, giving a year-round

growing season (Fig. 2.3).

5. Rainfall, temperature, and solar radiation lead to higher potential

evapotranspiration.

These characteristics describe the true tropics, on and near the equator, with

latitudinal changes toward the poles producing a variety of subclimates.

Even near the equator, mountain ranges and other geographical factors

can produce various subclimates. Since temperature, solar radiation and

photoperiod are fairly constant in the tropics, the variety of subclimates and

vegetation are frequently dependent upon rainfall.

A continuous succession of climates starts with a long season of well-

distributed precipitation and a short dry season close to the wet tropics. As

you move away from the equator and the latitude increases, there is a gradual

change to a short season of relatively low rainfall with a long dry season.

Some seasonal variation in mean daily temperature becomes apparent, with

cool temperatures increasing with increasing distance from the equator.

Table 2.1. Day length extremes in hours and minutes at various latitudes in the

tropics and subtropics.

Latitude º 0 10203040

Longest day 12:07 12:35 13:13 13:56 14:51

Shortest day 12:07 11:25 10:47 10:04 9:09

14 Chapter 2

Tropic of Cancer

Tropic of Capricorn

Equator

Fig. 2.2. Seasonal rainfall distribution in the tropics (after Bluthgen, 1966). The mottled areas are those that receive rain throughout

the year. The horizontal hatching indicates the wet and dry tropics with seasonal rainfall. The vertical hatching indicates the dry

tropics and monsoon areas with long dry periods.

The Tropics, its Soils and Horticulture 15

MAJOR TROPICAL CLIMATE TYPES

Many geographers and climatologists have classiﬁ ed climates into zones by

temperatures (tropical, temperate and frigid zones), by vegetation or crop

requirements, precipitation, altitude, soils, human responses, or by combining

these factors. A well-recognized classiﬁ cation system is the Köppen system,

named after the Austrian botanist and geographer, Wladimir Köppen. This

classiﬁ cation is based on temperature, rainfall, seasonal characteristics and

the region’s natural vegetation and was developed from 1870 to his death in

1940. The newer systems have most often been built upon the 1918 scheme

of the world climactic regions (Table 2.2). Another well-known modiﬁ cation

is that of C.W. Thornthwaite (1948), who based his classiﬁ cation on

distribution of e ective precipitation (P/E (precipitation/evaporation) ratio),

temperature e ciency and evapotranspiration. This led to nine moisture and

nine temperature regions. Numerous other classiﬁ cations have been published

based upon similar criteria (Oliver and Hidore, 1984; Schultz, 2005).

The classiﬁ cation systems of Köppen, Thornthwaite and others are

focused on the major factors (temperature, precipitation and evaporation)

that limit vegetation growth and hence horticultural production. The 18°C

Fig. 2.3. Solar radiation received at the earth surface at different latitudes and an

atmospheric coefﬁ cient of 0.6 (Gates, 1966). Solar radiation changes signiﬁ cantly

between the summer and winter periods as you move away from the equator. The

data in the ﬁ gure are for the northern hemisphere.

16 Chapter 2

Table 2.2. Köppen’s major climates based upon four major temperature regimes, derived from monthly mean temperatures, monthly

precipitation and mean annual temperature: one tropical, two mid-latitudes and one polar. The second division is based on moisture

availability. The system does not completely agree with natural vegetation and climate, and frequently the boundaries are rigidly

interpreted.

Principal climatic types Temperature (°C) Rainfall

Tropical Rainy Coolest month > 18 >600 mm driest month, range 2000 to 4000 mm per year

Wet and dry

Seasonal rainfall

<600 mm driest month, range 500 to 1500 mm per year

Dry Steppe Evaporation > precipitation, 100 to 500 mm per year

Desert

Mid-latitudes Mediterranean Coolest month < 18 3 × more precipitation in winter than summer

Mild winter Wet and dry > −3 10 × more precipitation in summer than winter

Rainy ≥ 30 mm per month

Mid-latitudes Wet and dry Coolest month < −3

Cold winter Rainy Warmest month > 10

Polar Tundra Average warmest month 0 to 10

Ice cap Average warmest month < 0

The Tropics, its Soils and Horticulture 17

boundary of Köppen recognizes the dramatic slowing of tropical plant growth

and development at lower temperature. At temperatures less than 10–12°C

and above freezing, most plants that evolved in the tropics stop growing and

are injured, depending upon length of exposure and species; this response

is called chilling injury. Precipitation and evaporation signiﬁ cantly impact

natural vegetation and subsistence agriculture, although irrigation does allow

horticultural production to proceed.

Several major tropical climatic types have been described:

1. Wet tropics: The wet equatorial or humid tropics, equatorial zone or tropical

rainforest occurs within 5–10° of the equator. It is characterized by constantly

high rainfall, humidity and heat. Rainfall is well distributed and may range

from 2000 to 5000 mm or more annually. Solar radiation is reduced due to

cloudiness. Vegetation is luxuriant on very weathered soils. Undisturbed, the

soil supports natural vegetation very well, but under cultivation the soils lose

their organic matter and porosity rapidly. Much of the land in the wet tropics

is undeveloped and in some areas unpopulated. Attempts have been made to

improve productivity, but past attempts by private industries and government

agencies have often not succeeded.

This wet tropics climatic type is common in parts of Africa within the 10°

N and S latitudes and includes the Congo Basin, Gulf of Guinea in West Africa,

parts of Kenya and Tanzania in East Africa; in South America the Amazon

Basin of Brazil and countries bordering the basin, such as French Guiana,

Guyana, Surinam and Venezuela; and in South-east Asia most of Malaysia,

Indonesia, Papua New Guinea, the Philippines and some Paciﬁ c islands.

The wet tropics are not limited to the above areas and are also widespread in

countries bordering the equator.

2. Wet and dry tropics: This is also known as the monsoon rainforest, with

marked seasonal rainfall between 5

and 15° N and S of the equator and as far

north as 25° in parts of tropical Asia (Fig. 2.2). Walter (1973) extended this

zone from about 10°

N and S to about 30° N and S latitudes. Maximum rainfall

occurs in the summer when the sun is directly overhead, with the dry season

in the cooler months. A tropical fruit horticulturist will probably spend most of

their time in this climatic zone.

This wet and dry tropical climate is found in a wide region of Africa, Asia,

the Americas, Australia and the Paciﬁ c tropics. Many tropical fruit species are

well adapted to wet–dry climatic conditions. For fruit production, some form

of irrigation is necessary, especially in areas where the wet season is relatively

short. A dry period in winter may substitute for cool temperatures in crops

requiring some stress prior to ﬂ owering. However, irrigation is desirable once

ﬂ owering begins and during fruit development.

3. Dry tropics: Also called the tropical savannah, occurs to the north and

south of the monsoon climate zone along the Tropics of Cancer and Capricorn,

between 15°

and 20°

N and S latitudes. It is characterized by hot, dry desert

18 Chapter 2

conditions where crop production cannot succeed without irrigation. This

climate is found in North Africa, bordering the Tropic of Cancer, north-east

India, Australia and parts of the Paciﬁ c coast of South America. The coast of

Peru has arid plains and foothills and fertile river valleys. For example, average

annual rainfall for the town of Piura on the north-western coast is 51 mm,

and average minimum and maximum temperatures are 17.6°C and 30.5°C,

respectively. Thousands of hectares of land remained unproductive due to lack

of irrigation until large dams were built to produce hydroelectric power as well

as to provide irrigation.

ALTITUDINAL CLIMATES

Climates change with altitude at the same latitude, and the change is related to

temperature. The environment can be divided into three temperature zones at

the equator: the hot zone, from sea level to 1000 m; the temperate zone, from

1000 to 2000 m; and the cool zone, above 2000 m, with frost occurring at

approximately 5000 m at the equator. Temperatures in these zones di er with

changes in latitude, prevailing wind patterns, precipitation and other factors.

In the Selva region of eastern Peru with large rivers, principally the

Amazon, two subclimates are recognized in terms of altitude and rainfall.

The low jungle or humid tropics extends from sea level to 800 m and has

rainfall throughout the year. The high jungle or central Selva, located between

800 and 1500 m above sea level, has a wet and dry climate, with about 6 to

7 months of wet season and the remainder with little or no rain. In the low

jungle, subsistence agriculture prevails, with crops such as co ee, cacao,

banana, mango, papaya, pineapple, soursop, citrus, black pepper, cassava and

poma rosa (Syzygium malaccensis). Under large-scale commercial cultivation,

some of the traditional crops, such as mango, papaya, pineapple and citrus,

would do better at latitudes somewhat removed from the equatorial region,

having better soils and reduced disease problems associated with high rainfall.

The high jungle (wet and dry tropics) in the central Selva area of Peru is better

developed, with farms of large commercial size. Citrus (Valencias, mandarins

and limes) and co ee have done well.

SUBTROPICS

Strict separation of tropical, subtropical and temperate climates is not

practical because of the many factors that inﬂ uence climate. Even within

the geographical limits of the tropics, there are areas that are subtropical

and temperate, or even frigid, because of altitude, topography, ocean and air

currents. The subtropics occur between the two tropics and about 40° latitude,

with summers being hotter and winters cooler than in the tropics. Humidity is

The Tropics, its Soils and Horticulture 19

generally lower in this region, and the di erence in day length becomes greater

with higher latitude (Table 2.1). The limit for the subtropics is the isotherm of

10°C average temperature for the coldest month. This 10°C isotherm excludes

the large land masses whose climates are temperate and includes almost half

of China, three-quarters of Japan, all of South Korea, the southern half of the

United States, all of the southern half of Australia, the North Island of New

Zealand and more than half of Argentina and Chile between 23° 30′ and 40°

latitude.

Horticulturists who have spent their professional careers in regions where

the temperatures during the coldest month at sea level are rarely lower than

15–18°C ﬁ nd it di cult to accept the tropical classiﬁ cation of regions with

winter temperatures down to 4–7°C and frost potential.

CLIMACTERIC FACTORS

Day length

The day length at the equator is about 12 h. At low latitudes in the tropics, the

increase in di erence between the longest and shortest days is about 7 min per

degree (Table 2.1), increasing to 28 min per degree at latitudes between 50

and 60°. The di erence in photoperiod (Table 2.1) is associated with the earth

being inclined on its axis by approximately 23° 30′; hence the solar equator

moves about 47° as the earth moves around the sun. The extremes are the

Tropic of Cancer (23°

30′ N) to the Tropic of Capricorn (23°

30′ S); within

this belt the sun’s rays are perpendicular at some time during the year. At

the spring and autumn equinoxes, the lengths of the day and night are equal

everywhere over the earth.

Fruit trees such as mango, papaya, bananas, the annonas, avocado,

acerola and guava show no response to photoperiod and are capable

of ﬂ owering at any season of the year. In equatorial Colombia, with

approximately 12-h day length, it is common to ﬁ nd mango trees ﬂ owering

during February–March and again in August. In the subtropics, ﬂ owering is

more precise, occurring in the spring as a function of lower temperature and

moisture availability limiting growth. For guava, seedlings grown under 15-h

day length from germination to 140 days and ﬁ eld transplanted produced fruit

within 376 days from sowing; the control seedlings under 10-h day length did

not ﬂ ower. This result with guava reﬂ ects the longer period available each day

for photosynthesis and not photoperiodism. Guava can also be forced to ﬂ ower

by pruning.

Pineapple can ﬂ ower naturally at any time of the year, depending upon the

size of the planting material, though it is a quantitative, but not an obligatory,

short-day plant. Interruption of the dark period by illumination suppresses

20 Chapter 2

ﬂ owering. Though pineapple does not require low temperatures or diurnal

variations in temperature to ﬂ ower, there is an interaction with temperature.

Temperatures lower than 17°C during short days can induce considerable

ﬂ owering, even in small plants. No ﬂ owers are produced on yellow passion

fruit (Passiﬂ ora edulis f. ﬂ avicarpa) vines under artiﬁ cially induced short days

(8 h). Long days promote passion fruit vine growth and ﬂ owering, while short

days promote vine growth only. This observation, however, could be due to the

amount of solar radiation received and not photoperiod.

Radiation

When compared to higher latitudes, the tropical latitudes have small seasonal

variation in solar radiation along with high intensity. The longer summer

day length at the higher latitudes means that these latitudes exceed the

daily amounts of solar radiation received in the tropics. The highest annual

energy input on the earth’s surface, 12 MJ/m

/day, occurs in the more cloud-

free subtropical dry belt of 20–30° (Fig. 2.3). In the tropics, solar radiation

received is reduced by clouds and water vapour in the air, through reﬂ ection

and absorption, to a minimum of ~7 MJ/m

/day at the equator. Over a large

portion of the tropics the average is 9 MJ/m

/day ± 20%.

In the tropics, atmospheric radiation transmissivity varies from 0.4 to

0.7, due largely to clouds and seasonal variation. The maximum recorded

irradiance under cloudless skies at noon in the tropics is 1.1 kW/m

, with a

daily total received of from 7 to 12 MJ/m

. About 50% of this energy is in the

0.4–0.7 μm waveband, which is known as photosynthetically active radiation

(PAR). In full sunlight, C

plants, including all fruit crops discussed in this book

except pineapple, which is a CAM plant, are ‘light’ saturated. This saturation is

due to ambient CO

availability limiting the rate of photosynthesis.

High shade (3–5 MJ/m

/day) does not inﬂ uence litchi ﬂ owering, though

it does increase early fruit drop. Flowering in passion fruit is reduced once

irradiance falls below full sun. Irradiance is normally not a factor limiting

plant growth in the tropics except during heavy mist and cloud, and in shade

from other vegetation and mountains.

Temperature

Near the earth’s surface, temperature is controlled by incoming and outgoing

radiation. Surface temperatures are modiﬁ ed spatially and temporally

throughout the year by local factors more than radiation. The main factors are

continentality, the presence of large inland waterbodies, elevation modiﬁ ed by

prevailing topography, and cloudiness. Highest diurnal temperatures occur

in dry continental areas, at higher elevations and in cloud-free areas. The

The Tropics, its Soils and Horticulture 21

rate of decrease in temperature with elevation (adiabatic lapse rate) varies

with cloudiness, hence season, and between night and day. The normal rate is

about 5°C per 1000 m under cloudy conditions and can range from 3.1 to 9°C

per 1000 m.

The human sensitivity to temperature is modiﬁ ed by the rate of

evaporation. Evaporation from human skin is primarily inﬂ uenced by

humidity, wind speed and response to sunshine. A human can endure high

temperature if the humidity is low; hence the discomfort felt in the humid

tropics is associated with high temperatures and humidity (>25°C and >80%

R.H.). These conditions are also favorable to growth of microorganisms and

insects. The problem of controlling plant diseases and insect pests in the

tropics is compounded by the absence of a cold winter and aridity to limit their

adult development.

Tropical fruit crops such as mango, guava, acerola, papaya, pineapple,

some annonas and others originated in the warm, lowland tropics. Others

such as the litchi, Mexican and Guatemalan races of avocado, cherimoya

and purple passion fruit are subtropical fruits by virtue of their origin in

the subtropics or at higher elevations in the tropics. Man, in his attempt to

commercialize tropical fruit crops, has extended production into subtropical

regions beyond the Tropics of Cancer and Capricorn and has generated

considerable knowledge on the range of temperature adaptability of these

crops. Data on threshold temperatures and durations of exposure for various

stages of plant development of tropical fruit trees are often unavailable;

minimum temperatures in the coolest month that support survival,

commercial or best production have been approximated (Table 2.3). The

minimum temperature criterion takes into account di erences in elevation and

latitude. In regions subjected to marginal winter temperatures, site selection

becomes a paramount consideration, such as southern-facing slopes in the

northern hemisphere and northern-facing slopes in the southern hemisphere.

Young plant growth may also be inhibited when soil temperature exceeds

35°C, a common condition in the tropics. Leaf temperature can exceed air

temperatures by 20°C; for example, pineapple fruit and leaf temperature have

been recorded in excess of 50°C in the ﬁ eld. Hence, maximum temperatures

in the orchard microclimate need to be considered in site selection. Three

crops (mango, litchi and avocado) illustrate this temperature adaptability and

the varietal and race adaptation at various stages of development. Mature

mango trees have been found to withstand temperatures as low as −16°C for

a few hours with some injury to leaves. Flowers and small fruits may be killed

when temperatures less than 4.5°C occur for a few hours during the night.

Mango varietal di erences for cold resistance have not been observed. Mango

responds to cool night temperatures (10–14°C) with profuse ﬂ owering. Ideally,

day temperatures during this period should be warm (21–27°C). When winter

night temperatures are mild (16–18°C), ﬂ owering is more erratic.

22 Chapter 2

Vegetative and ﬂ owering behaviour of litchi is very similar to mango,

except that it is adapted to even lower minimum temperatures than mango.

The total duration of relatively low temperatures seems to be the determining

factor rather than the frequency or time of occurrence during a critical

period. There are considerable cultivar di erences in the temperature exposure

necessary to induce ﬂ owers, e.g. ‘Brewster’ litchi ﬂ owers better in seasons with

200 or more h of temperature below 7.2°C. Other cultivars ﬂ ower profusely

when night temperatures of 14–15°C occur.

The three races of avocado originated under di erent ecological

conditions. The West Indian race is best adapted to humid, warm climates,

with the optimum around 25–28°C. It is susceptible to frost, and the mini-

mum temperature tolerated by the foliage is recorded at 1.5°C. Mature trees

of the Mexican race have shown tolerance to as low as −4 to −5°C without

damage to foliage, although ﬂ owers are damaged. The Guatemalan race is

adapted to a cool tropical climate but is less tolerant of low temperatures than

cultivars of the Mexican race. The leaves of the Guatemalan cultivars have

Table 2.3. Guidelines for survival, commercial and best production of tropical fruit

based upon mean minimum temperature in the coldest month (after Watson and

Moncur, 1985).

Crop Botanical name

Mean minimum temperature (°C)

for coolest month

Survival Commercial Best

Acerola

Malpighia glabra

10–12 >12 >14

Banana

Musa spp.

6–8 >8 >16

Breadfruit

Artocarpus altilis

14–16 >16 >16

Carambola

Averrhoa carambola

6–8 >8 >14

Chempedak

Artocarpus polyphema

12–14 >14 >16

Cherimoya

Annona cherimoya

4–6? 5–12? 6–10?

Durian

Durio zibethinus

14–16 >18 >18

Duku and langsat

Lansium domesticum

12–14 >14 >18

Guava

Psidium guajava

4–8 >8 >14

Jackfruit

Artocarpus heterophyllus

6–10 >10 >14

Longan

Dimocarpus longan

4–8 8–18 8–14

Litchi

Litchi chinensis

4–8 >14 >16

Mango

Mangifera indica

6–8 >8 >12

Mangosteen

Garcinia mangostana

10–14 >14 >16

Papaya

Carica papaya

6–8 >8 >14

Pineapple

Ananas comosus

6–8 >8 >10

Rambutan

Nephelium lappaceum

8–12 >12 >14

Sapodilla

Manilkara zapota

6–10 >10 >14

Soursop

Annona muricata

6–10 >10 >16

The Tropics, its Soils and Horticulture 23

shown tolerance of light frost down to −2°C, with ﬂ ower damage by even light

frost. The Mexican–Guatemalan hybrids, such as ‘Fuerte’ have shown wider

tolerance of cold than the Guatemalan cultivars. Temperatures of 12–13°C

during ﬂ owering can prevent growth of pollen tubes and embryos, leading to

production of unfertilized, underdeveloped fruits.

Rainfall

Temperature determines agricultural activity in the temperate regions of the

mid-latitudes, while rainfall is the crucial factor in the tropics. The seasonal

and diurnal distribution, intensity, duration and frequency of rainy days

vary widely in the tropics, both in space and in time (Fig. 2.2). The maximum

rainfall occurs near the equator, with no dry season. Surrounding this

equatorial zone in Africa and South America are areas with two rainy seasons

alternating with two dry seasons; rarely are the seasons of the same duration

or intensity. Further from the equator is a region of minimum rainfall at

20–30° latitude, associated with the subtropical high pressure area, with one

rainy season, frequently due to the monsoons. Topography can signiﬁ cantly

modify the generalized rainfall pattern; examples include the western coast

of India and Borneo, and the coastal areas of Sierra Leone, where monsoonal

winds are forced to rise because of mountain ranges. Trade winds can bring

considerable rainfall and are subjected to the forced rise by topographical

features. Other factors inﬂ uencing rainfall include changing and slowing

down of wind speed as it approaches the equator and continentality, such as

in south-west and central Asia. The above factors lead to complicated rainfall

patterns, with broad generalization possible while remembering that there is

considerable variation (Fig. 2.2).

Tropical fruit production is normally limited by available soil moisture. The

stage of growth or development at which water stress occurs greatly a ects the

ﬁ nal yield and quality. Many factors inﬂ uence the amount of rainfall available

to plants, including evaporation and transpiration rates, surface runo , soil

water-holding capacity and percolation through the soil proﬁ le beyond the

rooting area. Using the average tropical daily net radiation of 9 MJ/m

and

the latent heat of vaporization for water (2.45 MJ/kg), an evaporation rate of

ca 4 mm per day can be calculated. This evaporation rate is similar to that in

a temperate summer. Higher rates of 10–15 mm per day occur for irrigated

crops in the semi-arid tropics due to the advection of hot, dry air. Rainfall and

irrigation need to make up this evaporative loss, and a mean monthly rainfall

of 120 mm (~4 mm per day) would be required.

Excessive rainfall causes major problems with ﬂ owering, pests, diseases and

fruit quality. Many trees, such as mango and litchi, require a dry (or cold) period

to stop vegetative growth and induce ﬂ owering. Mango and litchi originated

in areas with a monsoon climate that provides distinct wet and dry seasons.

24 Chapter 2

Dry conditions, preferably accompanied by cool temperatures during the pre-

ﬂ owering period, promote ﬂ owering, while cool, wet conditions reduce ﬂ owering

in both crops. When mango ﬂ ower buds begin to emerge, some soil moisture is

needed, preferably from irrigation rather than from rainfall. Light rain during

mango ﬂ owering leads to severe anthracnose (Colletotrichum spp.), which can

destroy most of the inﬂ orescences. Too much rain during litchi anthesis also

reduces ﬂ ower opening and/or the insect activities needed for pollination.

Total rainfall is frequently less important than its distribution throughout

the year. In Loma Bonita and Acayucan, Mexico, two large pineapple-

producing areas, mean rainfall over a 5-year period was 1600 mm and 1500

mm, respectively. These approximate the upper limits of the optimal range for

pineapple; however, periods of serious drought are encountered, as 89 and

82%, respectively, of the rainfall occurs from June to November. In a tropical

rainforest, 85% of a 1 mm shower may be intercepted by plants, but only 12%

of a 20 mm rainfall, indicating that fall intensity, duration and frequency are

signiﬁ cant factors. The interception by plants is signiﬁ cantly inﬂ uenced by

species; pineapple with its upright leaves funnels water to the centre. Plant

density similarly a ects rainfall interception.

Orchards located on ﬂ at lowland areas can experience ﬂ ooding during the

rainy season, particularly if drainage is poor. This is important for avocado,

papaya, litchi and pineapple, for which waterlogging causes severe root-rot

problems. Mango is slightly ﬂ ood-tolerant, as indicated by reductions in leaf

gas exchange, vegetative growth and variations in tree mortality. Mangosteen,

by contrast, grows well under conditions of ﬂ ooding and high water table.

A high water table may prevent mangosteen trees from experiencing the

moisture stress needed to induce ﬂ owering.

Water deﬁ cit, and therefore irrigation demand, is determined by

evaluating rainfall, evaporation and soil water storage. The two most common

approaches are the water balance (rainfall, evapotranspiration, water

storage, change in the root range, surface runo ) and actual soil moisture

measurement. The crop needs, along with the soil type, determine frequency

of irrigation; this determination should be made on at least a weekly basis for

fruit crops. The use of drip (trickle) and micro-sprinkler irrigation enables a

grower to match the needs of the crop to irrigation needs at di erent stages of

growth and development, avoiding the need to rely on rainfall. These irrigation

methods allow precise placement of the water, reduce surface evaporation and

seepage, and increase water-use e ciency. Other irrigation methods used are

basin, furrow, overhead sprinklers and cannons.

Strong winds, frost and hail

In the equatorial zone, strong winds are associated with localized thunder-

storms (diameter <25 km) having greater intensity than those in the middle

and upper latitudes and lasting from 1 to 2 h. Most occur outside the 0–10°

The Tropics, its Soils and Horticulture 25

latitude zone (Fig. 2.4) and are convectional in origin and associated with

intense solar heating. Other strong winds can be due to sea or land breezes and

unstable warm and humid air masses. Hail occurs rarely in the tropics except

in the highlands, though it is known to damage tea in Kenya and tobacco in

Zimbabwe.

Tropical cyclones (hurricanes, typhoons) are an almost circular storm

system, ranging in diameter from 160 to 650 km and winds from 120 to

200 km/h, originating over water in the warm summer season. Most develop

within latitudes 20° N and S of the equatorial belt and may turn north-east

in the northern hemisphere or south-west in the southern hemisphere to 30–

35° latitude (Fig. 2.4). These systems bring violent winds and heavy rains. The

Philippines are very prone to such systems. Crop damage, especially to trees,

can be very severe due to the high winds.

Monsoon depression is a less intense weather phenomenon. It brings 80%

or more of the precipitation to the Indian subcontinent, with considerable

year-to-year variation. It occurs when there is at least a 120° directional shift

in prevailing wind direction between January and July. It is a characteristic

of the wet and dry tropics and spreads from Asia to Africa. The intensity of

rainfall can lead to considerable ﬂ ooding.

In the subtropics, frost is a major limiting factor to tropical horticultural

production. In isolated tropical high mountainous areas, frosts can occur

frequently. Frost in the subtropics is associated with incursions of cold air

masses (advection frost), while on tropical mountains it is mainly due to rapid

cooling on clear nights (radiation frost).

Trees have inherent di erences in the degree of resistance to winds, but all

fruit species beneﬁ t from wind protection. Mango, acerola and guava exhibit

greater resistance than other tropical tree crops such as banana, to the extent

that they survive strong gusts of wind without losing limbs or being blown

down. Leaves, ﬂ owers and fruits are often completely blown away. Pineapple,

by virtue of being low growing, gives the appearance of resistance, but wind

can damage leaves, and during the fruiting period the peduncles may be

broken, resulting in loss of fruit. However, windbreaks are almost never found

on pineapple plantations. The annona species, avocado and litchi are known

for their brittle branches and show limb splitting even under moderate gusts

of 65–80 km/h. Limb braces are occasionally used to prevent splitting of

large limbs, forming ‘Y’ crotches on litchi trees. Guava trees propagated by

grafting have tap roots that provide substantial anchorage. However, guava

trees propagated by rooting cuttings or by air-layering are subject to uprooting

during the ﬁ rst 3 years, probably due to faster top growth than root growth.

Papaya plants and passion fruit vines are vulnerable to even moderate winds.

Papaya trees are easily blown over, especially if the soil is softened by heavy

rains. Passion fruit vines on trellises can be tangled and broken, or the entire

trellis may be blown down. Developing carambola fruit is easily bruised and

marked by rubbing on branches and adjacent fruits due to wind, reducing fruit

26 Chapter 2

Tropic of Cancer

Tropic of Capricorn

150 120 90 60 30 0 30 60 90 120 150 180

180

Equator

Fig. 2.4. Areas of tropical storm development, which can signiﬁ cantly inﬂ uence fruit production in the tropics (after Gray, 1968).

Tropical storms can uproot trees, break limbs and snap the top of the trees. For plants with large leaves, such as papaya and

banana, the leaves can be shredded, with signiﬁ cant loss in photosynthetic capacity.

The Tropics, its Soils and Horticulture 27

appearance and grade. Mangosteen trees may also require protection from full

sun during early establishment as well as from wind. Windbreaks for these

crops are standard practice (see Chapter 3).

Soils

Using the US classiﬁ cation system, soils are separated into ten groups, based

on parent material, soil age and the climatic and vegetative regime during

formation. Tropical soils are diverse, having formed from di erent parent

material and climatic conditions (Fig. 2.5). These soils have formed in areas

where the soil temperature at 50 cm di ers less than 5°C between the warm

and cool season. The parent rock materials are as di erent in the temperate

zone as in tropics; erosion and deposition are similar; soil formation can have

been from recent volcanic or alluvial ﬂ ood plains to 1 million years old. The

di erences in temperate regions lie in soil-forming factors such as glaciation

and movement of loess, which have not occurred in the tropics (Sanchez and

Buol, 1975).

The majority of tropical soils are found in US soil orders oxisols, aridisols,

alﬁ sols, ultisols and vertisols and are spread widely throughout the tropics (Fig.

2.5). The soil orders are separated on the presence or absence of diagnostic

horizons or features that indicate the degree and kind of the dominant soil-

forming process. It is very di cult to make generalizations about tropical soils

other than they have less silt than temperate soils and that surface erosion

and deposition have been more signiﬁ cant. There are greater volcanic deposits

in the tropics and a larger proportion of younger soils than in the temperate

region. Only a small proportion (2–15%) of the tropics has so-called lateritic

soils (oxisols and ultisols), deﬁ ned as soils that have high sesquioxide content

and harden on exposure (Table 2.4). The red colour of tropical soils does not

mean that they have low organic matter. For example, the average organic

carbon content in the top 1 m of a black North American mollisol is 1.11%,

while red, highly weathered tropical oxisols may have 1.05%, the reddish

temperate ultisols 0.4% and tropical ultisols 0.66%.

The more intensively farmed, fertile soils of the tropics cover about 18% of

the area and are alﬁ sols, vertisols, mollisols, and some entisols and inceptisols

(Table 2.4). These soils generally developed from alluvium and sediment and

are high in calcium, magnesium and potassium (Table 2.5). This gives them

a high base status with no acidity problem. Phosphorus deﬁ ciency can be

readily corrected. Larger groups of tropical soils (oxisols, ultisols and others)

are of low base status, highly leached and cover 51% of the tropics (Table

2.4). Phosphorus deﬁ ciency can be signiﬁ cant as it is ﬁ xed by the iron and

aluminium oxide in these soils, which also often have aluminium toxicity

problems, with sulfur and micronutrient deﬁ ciencies (Zn, B, Mo, S). However,

they have good physical properties. The high-base soils (aridisols) in tropical

28 Chapter 2

Tropic of Cancer

Tropic of Capricorn

Equator

150 120 90 60 30 0 30 60 90 120 150 180

Fig. 2.5. Soil-type distribution in the tropics (after Kalpage, 1976; Sanchez, 1976). Tropical soils are diverse, having formed from

different parent material and under different climatic conditions. Key: vertical lines – aridisols; cross-hatched – entisols; rising

diagonal lines – mollisols; declining diagonal lines – oxisols; and speckled – ultisols. D – aridisol; I – inceptisol; S – spodosol; V –

vertisols and X – mountain areas.

The Tropics, its Soils and Horticulture 29

deserts (14%) can be very productive with irrigation. Nitrogen deﬁ ciency

and sometimes salinity can be problems. The 17% covered by dry sands

and shallow soils are greatly limited in agricultural productivity. The most

important aspect is the development of management strategies for the di erent

tropical soils, taking into consideration their unique properties. Management

practices developed in temperate regions may not be directly transferrable.

Soil physical characteristics are of primary concern for tropical fruit

production, with soil nutrients being secondary because they can normally be

readily corrected. Soil texture and structure, soil water storage and drainage

are crucial. Deﬁ ciencies in these characteristics are major constraints to

production because they are di cult and expensive to correct. Under natural

conditions, most soils considered for fruit crops in the tropics have a good

topsoil structure. This includes the highly weathered oxisols and ultisols (Table

2.5). Loss of organic matter may lead to loss of structure and crusting of these

soils after heavy rains. Some soils, however, do not favour root development

due to a dense subsoil layer that needs to be broken during soil preparation to

avoid shallow root systems. Heavy machinery may also cause the formation

of a compact subsurface layer in medium-textured oxisols with low iron and

in ﬁ ne-textured oxisols. Low calcium and phosphorus and high aluminium

contents in the subsoils can also restrict root growth.

Tropical fruit crops have shown a wide range of soil adaptability and

have been observed to grow and produce well in a wide variety of soil types,

Table 2.4. Distribution of major soils in the tropics (after Sanchez, 1976; Sanchez

and Salinas, 1981).

Humid

tropics

(%)

Seasonal

(%)

Dry and

arid

(%)

Tropics

(%)

Highly weathered, leached, red or yellow

soils – (oxisols, ultisols, alﬁ sols)

36 61 2 51

Dry sands and shallow soils – (entisol–

psamments and lithic group)

10 33 58 17

Light-coloured, base-rich soils – (aridisols

and aridic groups)

0158514

Alluvial soils – (inceptisol–aquepts,

entisol–ﬂ uvents)

40 52 8 8

Dark-coloured, base-rich soils – (vertisols,

mollisols)

860326

Moderately weathered and leached soils –

(inceptisol–andepts and tropepts)

759344

% of tropics 24 49 27 100

Classiﬁ ed on number of rainy months: humid tropics, 9.5–12 months; seasonal, 4.5–9.5

months; dry and arid, 0–4.5 months.

30 Chapter 2

provided other factors are favourable. In some cases considerable management

skill is required to maintain the crops in good growth and production. Soil pH

can be corrected by liming during ﬁ eld preparation, with most trees preferring

pH 5.5–6.5. Papaya is one of the few fruit crops that is adapted to a wide

range of soil pH, growing and producing well in soil pH ranging from 5.0

to well into the alkaline range. Deﬁ ciencies in phosphorus associated with

adsorption and excess aluminium need to be addressed in the oxisols, ultisols

and some inceptisols. Soil organic matter can be maintained by use of manure,

ground cover crops and mulches to preserve soil moisture and structure, and

improve the rhizosphere. Magnesium, zinc and boron deﬁ ciencies may also be

encountered in some tropical soils, but these are relatively easy to correct in a

management programme. Saline and alkaline soils, along with deep peat soils,

should be avoided for fruit production because of their di cult nature. Acid

Table 2.5. Soil classiﬁ cation and main characteristics of tropical soils and orders.

Order Characteristic Agricultural productivity

Entisol Recent alluvium, also on barren

sands and near deserts. Lacks

signiﬁ cant proﬁ le

Some very productive alluvial soils

Vertisol Swelling clay. Cracks in dry

weather

Productive, difﬁ cult to till

Inceptisol Horizons forming, little accumu-

lation of Al or Fe oxides. Tropic

with long, wet season,

acid

Very prone to erosion, good if well

drained

Aridisol Deserts, little organic matter,

CaCO

, CaSO

and soluble

salts

Need irrigation to be agriculturally

productive

Mollisols Granular or crumbly soils. High

in silt and organic matter

Most productive worldwide

Alﬁ sol Humid regions soil with grey or

brown upper horizon and silicate

clay below

Good soils, prone to erosion, easily

compacted

Ultisol Highly weathered, acidic in moist,

warm tropical areas, moderate

fertility

Very productive, easily compacted,

prone to erosion, needs fertilizer

Oxisol Highly weathered, in hot, heavy

rainfall areas, deep clay of

hydrous oxides of Al and Fe, can

be very acidic, leached

Needs nutrients to be productive,

susceptible to erosion if left bare

Andisols Surface deposits of volcanic ash,

free draining, low bulk density

Erosion serious problem, high P

ﬁ xation, high Al and Fe ﬁ xation,

excellent structure, productive

The Tropics, its Soils and Horticulture 31

sulfate soils require specialized management strategies, such as raised beds, to

be productive.

A prime soil requirement for all crops is good drainage to prevent

waterlogging, which leads to root diseases. Drainage is crucial for crops that

are susceptible to Phytophthora root rot, such as avocado, papaya, passion

fruit and pineapple. Mango and avocado have been observed to show branch

dieback in parts of ﬁ elds in western Mexico with a water table around 50–60

cm below the soil surface.

CLIMATE CHANGE

Climate change is regarded as the most important threat facing the environ-

ment that will have a signiﬁ cant e ect on society and agriculture. For the

tropics, climate change is predicted to expand the tropical region, with

signiﬁ cant changes in temperature (2–5°C increase) and rainfall (more

variable). The predictions are made for large regions and the expectation is

that there will be less rainfall near the equator and more rainfall, with greater

variability, further away from the equator, in the current drier tropical zones

(Easterling and Apps, 2005; Cerri et al., 2007; Ingram et al., 2008).

The predicted direct environmental changes include freshwater avail-

ability, carbon and nitrogen cycling, land cover and soils. All these changes

will directly impact biodiversity and agricultural, including horticultural,

productivity. It is expected that the induced biodiversity changes will lead to

new pest and disease pressures and greater weed problems (Sutherst et al.,

2007). For example, aphids are expected to become an increasing pest because

of their low development temperature threshold, short generation time and

high dispersal ability. Pathogens may have higher growth rates and more

generations per growth season. Weeds, with their more rapid growth and

development, may be more favoured in comparison to crops.

SUMMARY

Whereas temperature is the major limitation to plant growth in temperate

areas, in the tropics rainfall plays that role. There is considerable variation

in tropical climates due to altitude, continentality and the presence of large

bodies of water. Disease and insect problems are more severe in high-rainfall

areas. Year-round plant growth is generally only limited in the tropics by

moisture availability. Good soils are available in the tropics, and the high

value of horticultural crops means that they can command the use of more

favoured areas.

32 Chapter 2

FURTHER READING

Ayoade, J.O. (1983) Introduction to Climatology for the Tropics. John Wiley and Sons, New

York.

Gepts, P. (2008) Tropical environments, biodiversity, and the origin of crops. In: Moore, P.

and Ming, R. (eds) Genomics of Tropical Crop Plants. Springer, New York, pp. 1–20.

Norman, M.J.T., Pearson, C.J. and Searle, P.G.E. (1995) The Ecology of Tropical Food Crops.

Cambridge University Press, Cambridge, UK.

Sanchez, P.A. and Buol, S.W. (1975) Soils of the tropics and the world food crisis. Science

188, 598–603.

Schultz, J. (2005) The Ecozones of the World: the Ecological Divisions of the Geosphere, 2nd

edition. Springer, Berlin.

(R.E. Paull and O. Duarte)

CULTIVATION

Growing tropical fruit trees is a long-term investment, with harvesting not

beginning for several years. The exceptions are the herbaceous fruit crops,

banana, plantain and papaya, which will start producing marketable yields

in less than 2 years. Perennial and herbaceous fruit crops involve large initial

investment costs for site selection, land preparation, varietal selection, planting

establishment, fertilization, irrigation, pest control, pruning and your own

management costs. For perennial trees these costs will continue for several

years before the trees come into full production. After the trees start to produce

marketable volumes of fruit, the largest cost is for labour, and this is during

harvesting. It is therefore very important to provide the best management

possible so that the trees start fruiting as soon as possible and are in the best

possible condition to maximize yield and fruit quality at the lowest costs.

MARKET ANALYSIS

Market analysis is the crucial ﬁ rst step in establishing a new orchard. This

analysis will determine where the demand is for the products you plan to

grow, how big the demand is and who are your competitors, and can the

market be expanded. This analysis will enable you to decide if you will be able

to sell the product at prices that will leave you with a proﬁ t. The most e cient

production methods and the best varieties will not make up for an inability to

sell your product. This detailed market analysis has to be done before venturing

into this activity. Additional components in this analysis include knowledge

regarding the best time of year for fruits to arrive in the markets for higher

prices and what the market desires with regard to varieties and fruit quality.

New or di erent varieties that have di erent quality characteristics (colour,

texture, aroma, taste) can increase demand for a fruit and expand the current

export markets and should be considered. Export markets are very competitive

and the quality, including fruit safety requirements, is much more rigorous

than for most local markets. Export windows when a fruit may command a

34 Chapter 3

premium price are becoming narrower. For many products, export markets

have variety-speciﬁ c quality requirements, with only one or a few varieties

being in demand. Export markets will also require you to meet certiﬁ cation

requirements with respect to how a product is grown and managed, working

conditions and environmental stewardship. An example of a certiﬁ cation

system is the European GlobalGap. All of these factors have to be carefully

analysed before starting this business.

LAND SELECTION

The ideal land for a fruit orchard should normally be fairly ﬂ at with a deep soil

of medium texture and good water percolation to enhance root growth. Soils

with poor drainage are prone to be waterlogged during heavy rains, which can

limit root growth and increase root diseases. Other soil chemical and physical

properties must also be evaluated before starting an orchard. Investing a large

amount of money in land that is not suited for the species to be grown will

normally mean reduced yields and increased production costs. Many times

the savings in purchasing cheap land with poor soil quality will be o set by the

negative economic returns. For an annual crop, if a mistake is made in land

selection and the wrong soil type is chosen, this will become obvious at the end

of the ﬁ rst cycle, while for perennial fruit tree crops with a long juvenile stage

it may take a number of years before the mistake is apparent. This mistake will

be felt every year, resulting in large investment of money spent, not returned,

or both. Careful land selection is therefore essential, and if you are not familiar

with the area, the opinion of an expert will help. A number of key questions

need to be answered (Fig. 3.1) before making a selection. A simple decision

tree (Fig. 3.1) ensures that you evaluate the more important factors that can

potentially impact production and economic return.

In many instances there is a tendency by farmers to plant fruit crops in

the worst areas of their property. Producing fruit is normally a long-term

investment and has large upfront costs of land acquisition, preparation,

planting, establishment and management, and the expectation is for high

returns. The best land available should be used for fruit crops in order to

obtain the best possible economic return. In some cases marginal lands that

are normally only suited for forestry or grazing can be used for fruit trees,

but there is no reason to expect optimal proﬁ ts. Irrigation systems using

drip and micro-sprinkler with fertigation can provide water and nutrients to

the plants, reducing the di erences in orchard productivity between good

and marginal soil types. The soil, in some situations, has become a place for

the roots to establish themselves and the plants get water and fertilizers from

the irrigation system, but these production technologies cannot correct the

problems associated with poor soils that are saline, have poor structure and

water percolation, frequently are waterlogged or have toxic levels of nutrients.

Cultivation 35

Land too steep Yes

Ye s

Make sure no negative effects for

new crop, otherwise discard

m Discard

Soil extremely heavy m Discard

Irrigation impossible, long dry season m Discard

Irrigation possible, long dry season m Irrigate if economic

Soil too shallow m Discard or prepare mounds

Very poor soil structure m Discard

Poor soil drainage m Drainage or subsoil if economic

Very high water table m Drainage if economic

Too many salts in soil m Leach if economic

Soil too acid m Raise pH with lime

Soil very alkaline m Lower pH with sulfur

Saline sodic soil m Normally discard

Hardpan or plow pan m Subsoil adequately

Soil poor in macronutrients m Add macronutrient before planting

Soil poor in organic matter m Add organic matter, green manure

Previous crop was the same m

Previous crop heavily root diseased m Avoid susceptible species, otherwise

discard

Persistent weeds m Choose clean land if possible

Heavy nematode infestation m

Add organic matter heavily, use non-

host crop or discard

USE LAND

Fig. 3.1. The major steps in deciding whether land is suitable for a tropical fruit

orchard are set out as a decision tree. Going through the questions allows a

decision to be made as to suitability.

Hardpan or plough pan

36 Chapter 3

Soil evaluation

The soil on the selected site should be appropriate for the species you plan to

grow to improve the chances of success. Soil preparation and management,

including liming to change the pH, provide some ﬂ exibility with a soil that has

a good structure. If the soil is improperly treated it will not provide the best

conditions for plant growth and production will not be the ideal.

The results from the physical analysis of the soil will determine its

texture and structure, water retention and drainage. These characteristics, if

unfavourable, can be very serious production constraints and are di cult and

expensive to modify. Most soils considered for tropical fruit crops have good

topsoil and subsoil structures. Since fruit trees often have deep root systems,

poor subsoil conditions, such as a perched water table, will not allow root

growth below it. Other subsoil problems, in addition to a high water table, are

associated with the existence of rocks or hard soil layers. The presence of a

heavy soil layer above a sandy layer or the opposite can lead to di culties for

water drainage. An easy way to determine this is to dig three or four trenches

to 2–3 m scattered over the planned site to evaluate the soil proﬁ le.

Soil chemical analysis will tell you the soil’s nutrient content, pH, salinity

and alkalinity levels, organic matter content and the presence of elements that

could be toxic. Soils with undesirably low pH (<4.5) are frequent in the humid

tropics. This acidity is corrected by incorporating lime during land preparation

and often during the life cycle of the crop. Liming should raise the pH to

adequate levels of around 5.5–6.5. Some crops can do well in a wide range of

pH values while others need a narrower range. A frequent problem in tropical

soils is low calcium and phosphorus levels and high aluminium availability,

in addition to magnesium, zinc and boron deﬁ ciencies. These deﬁ ciencies

can be corrected by an appropriate fertilization programme and liming. In

arid tropical zones, soils with high pH and low phosphorus availability, with

deﬁ ciencies in iron, copper, manganese and zinc due to the nutrient being in

a non-soluble, unavailable form, are common and most can be corrected by

fertilization. Soils with high salinity or alkalinity should be avoided since they

can be very costly to correct. The soil organic matter content should also be

adequate and be maintained or increased if necessary by the incorporation of

manure or green manure crops. Soil organic matter improves moisture and

nutrient retention, maintains soil structure and enhances biological life in the

root zone (see Chapter 2 for more information).

Irrigation water

The potential irrigation water’s quality needs to be determined. The salinity

and sodium level in relation to calcium and magnesium (sodium adsorption

ratio or SAR) are evaluated, as these parameters can cause problems with

Cultivation 37

perennial crops in arid zones (Table 3.1). The data will enable a decision to be

made on usage, as species and varieties vary in their salt tolerance, with some

crops being very susceptible to salt injury (Table 3.2).

Previous land usage

A replant problem can exist with some fruit crops. Peach trees are probably

one of the best examples in a deciduous fruit crop; replanting into old peach

orchard areas often leads to failure due to chemical substances left by the

initial crop that can a ect the growth of the replanted crop (allelopathy) (Rice,

1974). This is sometimes referred to as soil fatigue. Another cause of replant

problems can be due to fungi, bacteria or nematodes that were hosted by the

former crop. Plants of the Solanaceae family are very prone to being infected by

root fungal diseases, bacteria and nematodes, and therefore it is recommended

not to plant a species of this family right after another. Citrus are also known

to show this problem. In many cases, the only solution to this soil fatigue is

crop rotation, which can last as much as 10 years using di erent species,

including grasses, before planting the same crop again. The alternative is to

plant a crop that will not be a ected by the above factors.

Planning

The collection of all the above data before land preparation allows you to plan

and cost out the project before starting. Potential problems can be avoided by

in-depth planning and making decisions on species and variety, rootstock,

soil management practices, irrigation system and fertilization practices. The

analysis could also lead to the possibility of rejecting a particular ﬁ eld or farm

because the soil or water is not suitable for the fruit species to be grown. If the

grower lacks the proper background knowledge about these matters, a soil

specialist should be consulted to assist in making the right decisions to avoid

unnecessary expenses and future problems. Most tropical fruit crops have a

Table 3.1. Irrigation water quality for tropical fruit trees.

Water quality

Conductivity

(dS/m)

TDS (total dissolved

salts) ppm

No detrimental effects 0.25 175

Sensitive crops could be affected 0.25–0.75 175–525

May have adverse effects 0.75–2.0 525–1400

Salt-tolerant plants only 2.0–3.0 1400–2100

Unsuitable >3.0 >2100

38 Chapter 3

fairly broad range of adaptability and are grown in a wide variety of soil types,

provided other factors are favourable. Ideally the best soils and irrigation

waters should be used and, as with other crops, proper management is always

important to obtain an e cient and sustainable production.

It is normally assumed that fruit trees need a soil proﬁ le that is at least

0.5 m, and ideally more than 1 m, deep, so that roots can grow down to that

depth. This is not always the case since many tropical fruit trees are shallow-

rooted. In instances where the soils are much shallower, either because parent

rock is near the surface or because the water table is close to the surface, good

proﬁ table production can be obtained. Fields with a shallow water table can be

drained or fragile parent rock can be cracked by ripping. Soils with a ‘caliche’,

a natural hard, crusted layer of calcium carbonate found in arid zones, can be

ripped or a hole bored through to allow root penetration.

Table 3.2. Salt tolerance of different fruiting trees. Adapted from Campbell and

Goldweber (1985) and Maxwell and Maxwell (1985).

Good Moderate Fair Poor

Carissa (Natal

plum)

Coconut

Tamarind

Date palm

Akee

Bignay

Black sapote

Canistel (egg fruit)

Cattley (strawberry)

Guava

Fig

Governor’s plum

Imbu (Spondias

tuberosa)

Indian jujube

Jackfruit

Jelly palm

Key lime

Loquat

Mayan breadnut

Monstera

Pineapple guava

Pomegranate

Prickly pear

Pummelo

Purple mombin

Rose apple

Sapodilla

Spanish lime

Tangerine/mandarin

Wax jambu

Atemoya

Barbados cherry

(Acerola)

Cherimoya

Cherry of Rio Grande

Citrus (rootstock

dependent)

Custard apple

Grumichama

Illama

Imbe

Kei apple

Kumquat

Mamey sapote

Miracle fruit

Mulberry

Otaheite gooseberry

Persimmon

Pineapple

Pitomba

Soursop

Sugar apple

Surinam cherry

Wampi

White sapote

Ambarella

Avocado

Banana

Caimito (star apple)

Carambola

Cashew

Jaboticaba

Longan

Lychee

Macadamia

Mango

Papaya

Passion fruit

Strawberry tree

Cultivation 39

Weeds in some areas can be very di cult to control. Areas heavily infested

with aggressive and persistent weeds like nut sedge (Cyperus spp.), Johnson

grass (Sorghum halepensis), Bermuda grass (Cynodon dactylon), star grass

(Cynodon nlemfuensis) and others are best avoided. They can be eliminated but

it will take time, e ort and money.

Mountainous land

Fruit orchards are commonly located on fairly ﬂ at land, as steep and

mountainous land is more expensive to prepare and carry out ﬁ eld

management. The advantage of mountainous land is that it is often cheaper

and usually has not been used for any fruit crops previously and is more

likely to be free of many parasites, weeds and chemical residues common

in other areas. Mountain soils need to have good soil texture and depth to

allow for good root establishment and growth. Erosion can be a problem on

steep hillsides, so care has to be taken not to eliminate the low vegetation

and to plant on the contour to minimize erosion. Terraces built along the

contours often have deep soils, though these terraces are expensive to build

and maintain. Individual terraces for each tree are also used. Drainage will

normally not be a problem under these conditions.

Irrigation of steep hillsides can be di cult, especially in the arid tropics

or tropics with a long dry season. An expensive irrigation infrastructure is

needed, which includes tanks to store water at the highest elevation and

pumps to ﬁ ll the tanks. In older orchards, contour irrigation systems are seen,

with newer orchards using drip irrigation and micro-sprinklers. The ﬂ exibility

of drip and sprinkler systems is that they are not limited to ﬂ at land and can be

used very easily on steep hillsides and on stony or poorer soils. Once the water

is pumped to the tank at the highest part of the orchard, gravity can be used

with pressure compensation drippers. Pressure-compensated drippers emit

equal amounts of liquid along the system, with a range of supply pressure.

LAND PREPARATION

In virgin areas, land preparation for fruit crops can be as simple as just

removing the trees and other vegetation before digging a planting hole. This

approach was used by the companies for banana plantations in Central

America. In mountainous areas, land preparation is normally by hand or with

small motorized equipment; larger machinery normally cannot be used. Large

trees and bushes are removed with the low vegetation left, and individual

holes are dug for each tree. This could include making a small terrace with the

planting hole at the centre.

40 Chapter 3

A hard layer or hardpan can be present in previously cultivated land (Fig.

3.2). These layers can develop in soils that have been cultivated with heavy

equipment when the soil was too wet or where the plough passed many times

at the same depth (plough pan). This hard layer (Fig. 3.2b) is eliminated by

subsoiling or ripping of the soil deeper than the hard layer (Fig. 3.2c). This

disruption of the hard layer (Fig. 3.2a and b) will allow better root penetration

into the subsoil. Subsoiling involves using a heavy tractor or bulldozer pulling

subsoiling hooks or rippers that are set to rip to 50–200 cm (Fig. 3.2c), with

a second pass done at a 45° angle to the ﬁ rst pass (Fig. 3.2d). Some other

subsoiling techniques use a torpedo-shaped device that is pulled with a cable

and leaves an underground passage that improves water and air circulation.

This operation should normally be done when the soil is dry in order to be

e ective.

Subsoiling and ploughing can be used to incorporate any fertilizer or

amendment to the soil. Typical amendments include manure to increase

organic matter, sulfur to lower the pH or lime to raise it, or any element that will

be in big demand can be incorporated at this time, when it is easier than after

planting. Phosphorus and other elements can also be incorporated deeper into

the soil and will be more e ective, since mobility when applied on the surface

is very poor. If there are di erent soil layers, then subsoiling will also help to

mix and homogenize the layers, with large pieces of roots from the previous

crop normally being removed. When a very hard underground ‘caliche’ layer

is present, subsoiling is not normally practised but a hole is made through the

layer using an auger or pointed steel rods to allow roots to penetrate further

Extensive root growth

down the soil profile

Restricted root

growth

(a) (b) (c)

(d)

Hardpan

Little root growth

Foot with wings

Pan

Loosened soil

Pan broken up

Leg

Fig. 3.2. Root development of tree crops mainly occurs in the top metre of the

soil proﬁ le (a); a hardpan can restrict root growth (b) and the hardpan needs to be

broken by a subsoiler (c). The tine of the subsoiler rips through the hardpan and

allows roots to penetrate. Subsoiling should be done with two passes of the ﬁ eld at

about 45° to each other.

Cultivation 41

down the soil proﬁ le and for water to drain to the subsoil. Dynamite has been

used to crack superﬁ cial rocky soils, especially if the rocks are of coralline

origin or calcareous; this was done in large areas in Cuba. A small hole the size

of the dynamite piece is bored into the rock and then exploded to crack the rock

and leave a passageway for water and roots to penetrate.

Stones can be another problem during land preparation, though not as

much as with annual crops. Ideally all rocks and stones should be removed,

especially from the soil surface, in order to ensure that the machinery will

have no problems in moving around and will not be damaged. In very stony

areas, removal is uneconomic and only large and medium stones on the

surface are taken from the ﬁ eld so vehicles can move freely in the orchard and

mowing can be carried out. Stone removal should preferably be done after

subsoiling and ploughing, so that most large stones will be on the surface.

Often the stones are used to build boundary fences. Alternatively, the stones

are used to ﬁ ll depressions, holes or ditches in the ﬁ eld or throughout the farm.

The next step is ploughing the whole ﬁ eld, sometimes in two directions, with

large stones again being removed. Ploughing is followed by discing to break

up the larger clods and make the ﬁ eld ready for planting. Land levelling is

sometimes performed, especially if furrow irrigation is to be used; with drip or

micro-sprinklers this will not be necessary. If surface ﬂ ood or furrow irrigation

is used, the furrows need to be cut at this time, along with soil fumigation, if

required, and planting holes made.

DRAINAGE

Drainage is needed for most orchards, especially when the land is ﬂ at and the

soil has a low water percolation rate. Failure to provide drainage can mean

waterlogging and standing water remains in the ﬁ eld for more than a few

hours. Standing water in ﬂ ooded ﬁ elds means that the soil atmosphere will

soon become depleted of oxygen and become anaerobic. Anaerobic conditions

cause stress to most tropical fruit tree roots, limit nutrient uptake and make

the roots less able to resist soil-borne pathogens such as root rots due to

Phytophthora and other fungal pathogens.

Drainage is accomplished with ditches and sometimes with interconnected

subsurface drainage pipes. This can be an expensive investment. On gently

sloped land, plant rows are normally oriented to follow the maximum incline

so that the excess water ﬂ ows downhill. This orientation is possible if the slope

does not exceed 10%. When the slope is greater than 10% transverse ditches

will be needed to slow down the water speed, and these transverse ditches are

connected to the main drainage ditches. In mountainous areas, tree rows

normally follow the contour, so as not to create an erosion problem when it

rains. Swales along the contour or ‘French drains’, which consist of a system

of ditches ﬁ lled sequentially with stones and gravel and sometimes covered

42 Chapter 3

with soil, are used. These drains slow the rate of water ﬂ ow and allow the

water to inﬁ ltrate into the soil. In most cases, swales are left open and they

carry the water to a main ditch or creek. In heavy rains, these shallow swales

are overloaded and can lead to signiﬁ cant erosion.

Raised beds are recommended when root rot-susceptible crops such as

papaya, passion fruit, avocado and pineapple are grown on level land (Fig.

3.3). The deep furrows created between the beds drain away the excess water

(Fig. 3.3a). These furrows can be used for irrigation during the dry months.

In ﬁ elds with depressions or under wet or in heavy soils, planting the tree on

a mound reduces the problems due to waterlogging (Fig. 3.3b). The mound

height depends upon the magnitude of the ﬂ ooding problem, with around

25 cm being common. Taller mounds increase the orchard layout costs and

consideration should be given to ﬁ eld-levelling grading, leaving only a gentle

slope. Levelling or land shaping is practised in some pineapple-growing areas.

The shaping is done with heavy machinery by making a successive series of

wide and not very steep mounds so that the excess rainwater runs into their

lower parts, to be drained from the ﬁ elds. This shaping maybe done in addition

to the use of raised beds that are oriented so that their furrows conduct water

to the lower parts of the ﬁ eld.

The banana industry is very sophisticated in its drainage infrastructure

in the wet tropics. Bananas do not tolerate a high water table or long periods

of soil saturation. A successive series of parallel, open drains 1.2–2.5 m

deep every 40–60 m, referred to as tertiary drains, are dug. These drains are

designed to keep the water table at the desired depth and also to collect runo

that is not absorbed by the soil. Shallow drains (quaternary drains) are dug

(a) (b)

Fig. 3.3. Drainage is a major concern for tropical tree fruit production in areas with

high water tables or heavy rains. Trees are grown on raised beds (a) and planted on

mounds (b).

Cultivation 43

with shovels to the tertiary drains after a heavy rain to drain areas where

water accumulates in the ﬁ eld, so that the excess ﬂ ows into the tertiary drains.

Tertiary drains conduct the water to 2.5–4.0-m-deep secondary drains, which

in turn will drain the water into a river or creek or a primary drain that can be

2.5–6.0 m deep.

PLANTATION LAYOUT

A contour or ‘Google’ map of the farmland is ideal to start layout planning.

The map should ideally include the location of buildings, farm boundaries,

roads, fences, irrigation water supply and drainage ditches. Decisions are then

made on the direction and length of the tree rows, the number of plants, the

need for additional interior roads for transporting materials or products to

and from the ﬁ eld, and location of additional structures such as storage and

machinery sheds and packing facilities.

The length of the rows will depend on the type of soil and irrigation; if

irrigation is by furrows or basin, rows that are about 60–80 m long in light

soils and 120–180 m in heavy soils would be a starting point. Rows that are

too short are not convenient for e cient machinery movement. The direction

of the rows should take into account the water movement from both irrigation

and runo .

Using the layout map the easiest way to start in the ﬁ eld is to conﬁ rm that

the direction chosen for the tree rows on the layout map is the best and make

appropriate corrections in the ﬁ eld. Use a long string or rope stretched to follow

the direction chosen and then stake each end. These stakes serve to establish

a 90° angle at each end to start the geometric layout pattern. At each of the

ends use a measuring tape with the 0 m mark at the stake and mark the point

on the rope 3 m from the stake, then mark another point with a stake 4 m in

a perpendicular direction to the rope, adjust the position of this stake so it is 4

m from the end stake and 5 m from the 3 m mark on the rope. The 5 m line is

the hypotenuse of your triangle and a 90°

angle is formed at the stake. At the

other end of the rope repeat the same procedure, so you have two parallel lines.

Measure on both parallel lines an equal distance to conﬁ rm that the distance

between these two points is the same as the distance between the ﬁ rst two

stakes. If the same, then you have parallel lines, if not you will need to recheck

the two triangles so that a square or rectangle is formed. Then all four corners

are staked and new stakes are put in or the spots marked with gypsum or lime

at the distances the trees or rows will be and repeat on the other side. Then a

rope or wire is pulled between the matching stakes of the opposite sides and at

the perpendicular lines the same is done. Where the ropes or wires cross a stake

or a lime mark is left, which will indicate the location to dig a planting hole.

Orchards are usually planted following geometrical arrangements (Avilán

et al., 1989), depending on the land condition, the species, variety, plant

44 Chapter 3

shape, planned pruning and need for machinery. Planting layouts between

trees can be square (Fig. 3.4a), rectangular (Fig. 3.4b), an equilateral triangle

or hexagonal system (Fig. 3.4c) or some other combination, including extra

or temporary plants to increase returns during the initial juvenile years (Fig.

3.4d, e and f). If a rectangle layout is used (Fig. 3.4b), the trees will form this

geometric ﬁ gure; the longer side will correspond with the distance between

tree rows and the shorter side will be the distance between trees in the row. In

the square arrangement (Fig. 3.4a), the distances in both directions will be the

same, and in the equilateral triangle normally a plant will be planted in each

angle, forming triangles or a hexagon that has a plant in its centre (Fig 3.4c),

and this gives 15% more plants per area than the square system while leaving

the same distance between trees.

The rectangular layout is used when bulky machinery has to enter the

ﬁ eld, although in the square layout this can also be done in the initial years

also. Sometimes a square pattern can be used and every few rows a wider

row is included in the layout. The wider row is left to allow movement of

machinery. The location of the wider row will depend upon the length of hoses

or how far the sprayers can reach and the distance you need to move harvest

bins or boxes to facilitate fruit collection. Between-plant distances are shorter

for plantains, bananas and papayas, and in hilly conditions where heavy or

bulky machinery will not be used, normally a square or, better, a triangular

arrangement should be used. The distance between trees will be the same in

the square and equilateral triangle arrangement, with the latter resulting in

more plants per unit area.

To maximize early income, the quincunx (Fig. 3.4d) and other systems

are used. The quincunx consists of a square arrangement with a temporary

or extra plant at the centre of each square. This arrangement almost doubles

the number of plants per unit area and allows higher production during the

initial years. Another intensive initial planting system consists of planting a

temporary plant in the space between the permanent plants in the row (Fig.

3.4e); this will duplicate the initial number of plants. An even more intensive

initial planting system consists of planting three temporary plants for each

permanent plant. This intensive planting has an extra row of temporary plants

between two permanent plant rows and an extra temporary plant in all the

spaces between the plants in the rows, even in the temporary rows (Fig. 3.4f).

As the trees start maturing and yield increases, the extra trees are pruned and

later removed. This system is not recommended for all crops or all growers.

PLANTING DISTANCES

Planting distances will be determined by many factors, the most important

being the species. Tree size and shape can vary from large trees like mango

to small plants like papaya or banana. The variety can play a signiﬁ cant role,

Cultivation 45

a=b

Square

n years

Double density

X = Temporary plants

(a) (b) (c) (d)

(e) (f )

Fourfold density

n years n years

Quincunx

a>b

Rectangular

a = b, h < a or b

Hexagonal

(Equilateral triangle)

Fig. 3.4. Field layouts can be as a square (a), rectangle (b), hexagonal (c) or quincunx (d). In denser planting for the early

orchard years, a double planting (e) or a fourfold density (f) can be used – the plants indicated by ‘X’ being removed after a

number of years to avoid overcrowding. On steep land the layout may need to be modiﬁ ed with trees planted on the contour.

46 Chapter 3

with di erent growth vigour and habits. Varieties can be compact compared

to the traditional size, or their canopy shape can vary from wide to narrow.

Rootstocks will also play a vital role in tree vigour, varying from very vigorous

to dwarﬁ ng rootstocks. Sexually propagated plants are normally larger than

their asexually propagated counterparts. Another factor that can modify

distances is how large the tree will be allowed to grow and the pruning and

shaping carried out during initial growth. For example, a tree pruned into

a vase shape will be wider than a tree left with a central leader, while a tree

trained in a palmette system will be wide only in one direction. The severity of

pruning also plays a role.

Soil quality inﬂ uences ﬁ nal tree size, with trees grown in poorer soils

being smaller. Rainfall pattern and its amount in non-irrigated areas can also

reduce tree size. Sometimes the harvest practices, irrigation or the spraying

system can modify certain distances or at least make it necessary to leave some

broader spaces among certain tree rows. The exact distance will be di cult

to establish if the crop has never been grown in that area. An approximate

distance can be established, sometimes with the help of an expert (Table 3.3).

In the middle of the last century, orchards were planted at densities of

less than 250 trees per hectare; today, tree density ranges from 200 to 2000

plus trees per hectare. In the past, tree spaces were based upon the distances

required for the adult trees; this meant a lot of wasted space before the ground

area was covered by the canopies. This practice led to a higher cost of weed

control and spraying and increased harvest cost, as tall trees (>3 m) are more

expensive to collect fruit, requiring ladders and mechanical platforms. This

adult-form concept has now changed, with a more pressing need to recover

your initial investment as soon as possible and reduce your overall management

cost associated with large, tall trees. One system being used is to plant at much

shorter distances, and as the trees become larger, the so-called temporary

or ﬁ ller trees are pruned so as to reduce interference with the growth of the

permanent trees. Finally, the temporary trees are removed completely to avoid

further competition. A second thinning of the remaining trees is sometimes

performed once they have grown larger, in order to leave the ﬁ nal number of

trees per area. This system will require larger early investments in trees and

maintenance, which will need to be balanced against the larger returns and

income during this early orchard development period. In some situations, this

practice may not be worth the extra cost and alternatives such as short-cycle

vegetable crops or even widely spaced banana or papaya may be alternatives.

PLANTING

In a good soil with irrigation and which has been properly prepared, a planting

hole slightly larger than the container holding the root-ball can be used. This is

normally a 30 by 30 cm or a 50 by 50 cm hole made using shovels or augers.

Cultivation 47

A large hole may be used in poor-quality soils or in good-quality soils with no

supplementary irrigation that depend only on seasonal rainfall. A hole of 80

by 80 cm or 100 by 100 cm is ﬁ lled with a good substrate so that during the

initial years the plant will grow vigorously before the roots reach the poor or

dry soil area.

When the hole is dug, keep the topsoil in one mound and the subsoil in a

separated mound since they normally di er in quality, with the topsoil being

better. Before planting, mix the topsoil with organic matter such as matured

moist manure or decomposed co ee pulp or any composted product and ﬁ ll to

the 40–50 cm mark of the 80–100 cm depth, then topsoil is added to about

30 cm from the soil surface and compacted by stepping on the materials in

the hole. The topsoil without manure is placed next to the root-ball since

fresh manure can burn the roots as it starts decomposing if in direct contact.

Manure can burn the roots either by the elevated temperature produced by

decomposition or by the salts that it releases. If the manure is well decomposed

Table 3.3. Some examples of recommended between-tree and row spacings in

tropical orchards for some fruit crops.

Crop With ﬁ llers (m) Trees/ha

Permanent spacing

(m) Trees/ha

Acerola 2.7 × 5.5 673 5.5 × 5.5 332

4.6 × 5.5 395

Atemoya 4.5 × 9.0 247 9.0 × 9.0 124

8.0 × 12.0 104

Avocado 4.5 × 6.0 370 9.0 × 12.0 93

6.0 × 7.5 222 12.0 × 15.0 56

Fuerte 7.5 × 7.5 177 15.0 × 15.0 44

Hass 7.0 × 7.0 204 14.0 × 14.0 51

Cherimoya 5.0 × 6.0 333

5.0 × 7.6 263

Durian 10.0 × 10.0 100

Guava 3.1 × 7.6 424 6.2 × 7.6 212

4.6 × 7.6 286

Litchi 5.0 × 5.0 200 10.0 × 10.0 100

6.0 × 12.0 139 12.0 × 12.0 69

Mango 5.0 × 10.0 200 10.0 × 10.0 100

12.0 × 12.0 138 12.0 × 12.0 69

(+ one tree in

centre)

Papaya 2.4 × 3.1 1344

Passion fruit 3.3 × 4.0 1324

Sapodilla 6.6 × 6.6 400

Soursop 3.7 × 7.6 356 7.4 × 7.6 178

6.0 × 9.0 185

48 Chapter 3

or a composted organic matter is used, then it is not necessary to separate the

material and the hole can be ﬁ lled with the mixture of topsoil and decomposed

manure.

The root-ball can be set in place with a 20-cm-wide ring of topsoil around

it. The remaining part of the hole is then ﬁ lled with topsoil, or ideally with

the mixture of topsoil and composted organic matter, and compacted so the

plant stays ﬁ rmly in position, and the root-ball is in close contact with the

surrounding soil medium. This will allow new roots to grow rapidly into the

surrounding soil without problems. If the subsoil is of poor quality, topsoil

from neighbouring areas can be used and then these areas can be backﬁ lled

with the subsoil from the hole. It should be remembered that most of the

feeder root activity occurs in the upper 50 cm of the soil. Large holes provide

much better growing conditions than a normal hole. When establishment is

dependent upon seasonal rainfall and irrigation is not available, planting

should occur just prior to the wet season. It may be necessary to water the

plants under these circumstances using buckets during the ﬁ rst 2–3 years to

give the plant a much better start.

PLANTING MATERIAL

Often new growers will purchase planting material that is not of the highest

quality or the best variety. This practice leads to poor tree establishment, poor

yield or poor fruit quality. Having to replant an orchard is expensive and it

should be avoided. Plant quality is determined by several criteria.

Plant identity

Most tropical fruit trees are a combination of a varietal scion and a rootstock.

Alternatively, cuttings, air layers or vegetative organs like suckers and

runners are used. For herbaceous fruit trees such as papaya, seeds are used.

It is necessary to ensure the plants are the variety that you want. In grafted

or budded plants the identity of the scion has to be known, and in many cases

it is also very important to know what rootstock was used. Rootstock choice

is crucial for some fruit species, and it has to be a very speciﬁ c variety or type

in order to allow the tree to grow well under determined soil conditions in the

presence of certain plant pests and diseases and to produce good-size plants.

For some species, choice of rootstock is not so crucial, as it serves only to

propagate the desired variety by grafting or budding.

Cultivation 49

Plant health

The plant needs to be free of the most important diseases so that it does

not contaminate the ﬁ elds with new pests (disease, insect or nematode).

Occasionally, new weeds can be introduced via the substrate the plants were

grown in.

Anatomical and physical aspect

It is best to use plants that are anatomically well formed with a straight and

strong main stem (Fig. 3.5a). The plants should be healthy and vigorous and

be inspected to make sure they have a good root system and a straight stem

with a good caliper. There should be no pronounced bends in the ‘neck’ – the

zone that separates the root from the stem – which indicate an improper seed

or embryo position at sowing time. The bends in the neck are due to chance

or bad sowing position plus a lack of proper sorting of the seedlings when

transplanted to the containers, These seedlings should be discarded at the

time of the ﬁ rst transplant in the nursery or at the time of purchase. The bent

condition is more of a problem in seedlings from polyembryonic seeds like

citrus and mangoes of the Indochina–Philippine group. The mangoes of this

group form many embryos, which compete for the space that is normally for

one embryo, resulting in abnormal growth and entanglement and bending.

Plants with bends in the main roots at the bottom of the root-ball or with a

mesh of roots around it indicate they have stayed far too long in the container

(Fig. 3.5b). Ideally plants with these problems should be discarded. If needed

or because of scarcity of planting material they can be used, but the peripheral

roots have to be pruned away and the root mesh disrupted by making several

longitudinal cuts in this layer with a sharp knife. The objective is to ensure

that this abnormal growth pattern does not continue and that new roots

will emerge from the root-ball and grow outwards. When the primary root

at the bottom of the root-ball has a bend, it should be cut above the bend to

eliminate this abnormal growth pattern. This root pruning will result in root

loss and a plant with reduced water and nutrient absorption capacity. The

recommendation is to defoliate the plant to reduce potential transpiration and

balance the root absorption with leaf transpiration. Failure to defoliate can

lead to plant dehydration and death. This defoliation and root pruning will

retard plant growth and therefore all plants with manipulated roots should be

planted together in one area of the ﬁ eld so that they can be given additional

care. Their growth will be initially slightly behind the other transplants that

have intact roots. Similar procedures should be used if the root-ball cracks or

breaks during transplanting, or if too damaged then discard.

50 Chapter 3

ASSOCIATED CROPS OR INTERCROPS

After or before planting the trees, an associate crop can be started, in order

to maximize the use of land and, hopefully, get extra income during the ﬁ rst

years, which are the most di cult economically. This could be any annual

crop, including vegetables or a short-cycle fruit crop such as pineapple, cocona

(Solanum hyporrhodium) and naranjilla (Solanum quitoense). In some areas

intercropping in orchards with vegetables, leguminous crops and cucurbits is a

common practice. In Mexico, fruit orchards have been observed with excellent

intercrops of beans (Phaseolus vulgaris), watermelons (Citrullus vulgaris),

cantaloups (Cucumis melo var. reticulatus) and chilli (Capsicum annuum). Good

weed control is obtained under these intercropping systems.

In the second and third years, intercropping can be repeated, but the

soil should only be worked between rows at an increased distance from the

fruit trees each year. This reduction in cultivated distance is required to

avoid root damage, which can weaken the plants or become an entry point

for harmful organisms. It is normally recommended that after 3 or 4 years

no soil disturbance by heavy machinery should occur except for the pass of

mowers or brush cutters and the equipment for spraying and harvesting. An

alternative is to kill o the ground cover with herbicide and transplant the

intercrop directly without soil disturbance.

(a) (b)

Fig. 3.5. Nursery production of planting material is crucial for the successful

development of an orchard. Black plastic bags are frequently used (a). It is important

to ensure that the plants are not allowed to stay too long in the bag or they become

root-bound (b), with the roots growing around the outside of the medium against

the inside of the bag.

Cultivation 51

Short-lived fruit crops such as yellow passion fruit or papaya (Fig. 3.6) can

be planted between rows, and after 2 or 3 years they will normally be at the

end of their production cycle. Plantain and banana could be also used, making

sure their shade does not a ect the small trees; after a reasonable time they

can be eliminated and the propagating material taken to another location.

Care has to be taken during the ﬁ rst years not to allow any large plants to grow

close to the young fruit trees since they may check their growth and these

trees are your long-term priority. Pasture can be started, and the shadow of

the trees as they increase in size will eventually eliminate the pasture from the

more shaded areas under the canopy. This pasture, generally a legume, will

show little damage from this shade and can be used as a weed control crop.

The other alternative, discussed above under plant spacing, is to increase the

number of trees planted twofold to fourfold to increase early production with

no room left for an associated crop. All of these alternatives help the farmer to

increase his early returns. It is necessary to estimate the extra costs associated

with these alternatives against the extra income that could be expected, which

could be negative.

Ideally the best approach is to start the orchard with an associated crop

almost simultaneously, so that the initial land preparation serves both crops.

This approach can leave the soil undisturbed except for sowing the cover

crop at a later time, if needed. The associated crop should not host enemies

that could attack the fruit trees and should not produce substances that may

inhibit the tree growth. The fruit trees and the associated crop need a degree

of compatibility with respect to water needs or frequency of irrigation. An

associated crop can also complicate ﬁ eld practices such as spraying and hence

are not recommended after the third or fourth year.

(a) (b)

Fig. 3.6. Short-lived crops such as beans planted between rows of young avocado

trees (a) and papaya and banana planted between rows of the future crop of

rambutan (b) provide income during the juvenile period of the main crop.

52 Chapter 3

ORCHARD FLOOR MANAGEMENT

The physical and chemical properties of the orchard’s soil need to be

maintained in a good condition to ensure that root growth occurs without

di culty. However, weeds need to be controlled, people and machinery need

to move around in the orchard, and irrigation needs to reach all of the trees.

No single system can be used for all soil types as all have their advantages

and shortcomings. Rainfall, soil characteristics, irrigation system, water

availability, type of weeds, and the species and age of the trees should be taken

into account when deciding upon orchard management, without forgetting

costs and returns. The main orchard ﬂ oor management systems used are

mechanical cultivation, cover crops, mulching and keeping the soil bare with

herbicides, as used on the coralline sandy soils of Florida.

Cultivation with machinery is very e ective with annual weeds and it helps

break the crust that sometimes forms and allows incorporation of fertilizers

and organic matter. Its shortcomings are that, after the orchard is 3–4 years

old, disturbing the soil between tree rows is normally not recommended due to

the danger of damaging the root system and the entrance of some pathogen

through the wounded roots. The destruction of irrigation ditches or furrows

can be another problem with mechanical cultivation. The presence of pipes

and hoses limits the use of cultivation, and the multiplication of weeds with

underground structures (nutgrass) can be another problem. Shallow and

careful cultivation avoiding under the tree canopy should be done with o set

discs or equipment that scratches the soil. As the trees grow, the soil should be

worked at increasing distances from the tree canopy line (Razeto, 1993).

Temporary or permanent cover crops are an alternative, especially if there

is good moisture in the soil throughout the year (Table 3.4). These crops help

maintain good soil structure, increase water penetration, prevent erosion from

wind and rain, and keep soil temperature lower. In the humid tropics, a legume

such as kudzu or other suited legume species can be used, with the additional

beneﬁ ts that they ﬁ x nitrogen. Kudzu can be an invasive weed because of its

rapid growth and habit of climbing up and over trees. Extra management is

necessary to periodically cut the climbing shoots with a machete and change

the vines’ growth direction with the hands or a long stick.

Growing sod as a cover crop requires ample water and nitrogen in order

not to a ect tree production (Fig. 3.7a). Mowing or grazing is needed with sod,

with the extra advantage of allowing machinery to get into the ﬁ eld sooner

after rain and irrigation. On steep land, the presence of a cover will prevent soil

erosion during heavy rains. Aesthetically, sod is a good approach, but there is

strong competition for water and nutrients with the crop. In areas with a dry

season, the transpiration from the sod can be very high and it will also need

fertilizer, so care must be taken to irrigate and fertilize taking this additional

need into account. In the absence of irrigation, competition for water can be a

Cultivation 53

Table 3.4. Some tropical ground covers and green manures.

Name Main characteristics

Arachis pintoi

Forage or perennial groundnut.

Good coverage. Permanent. Non-climber. Will revegetate after dry

period. Shade tolerant.

Cajanus cajan

Calapogonium

mucunoides

Calapogonium caeruleum

Canavallia ensiformis

Jack bean

Toxic seeds. Green manure and ground cover. Very drought

resistant, shade tolerant and good for poor soils. Does not

tolerate excess water.

Canavallia gladiata

Sword bean

Uncooked seeds are toxic. Drought resistant. Green manure

Centrosema

pubescens

Clitoria ternatea

Butterﬂ y pea

Green manure. Very drought resistant. Small leaves will not cover

well.

Crotalaria juncea

For ﬁ bre extraction. Fairly toxic to cattle. Some drought tolerance.

Crotalaria ochroleuca

Sunn hemp

Green manure. Non-toxic cattle feed except seeds. Upright. Fairly

drought resistant.

Desmanthus virgatus

Wild tantan

Green manure or fodder. Drought resistant. Bushy plant grows

back quickly.

Desmodium adscendens

Desmodium ovalifolium

Shade tolerant. Climber.

Dolichos lablab or Lablab

purpureus

Lablab bean

Similar to velvet bean but for more fertile soils. Drought resistant.

Green manure and cattle feed.

Indigofera hirsuta

Hairy indigo

Nematode suppressant. Annual, will reseed itself. Ground cover or

green manure. For well-drained soils.

Medicago hispida

Garrotilla

Mucuna pruriens

Velvet bean

Green manure. Very palatable. Aggressive climber. Tolerates

drought and low soil fertility. Bushy growth.

Phaseolus cocineus

Scarlet runner

Psophocarpus

tetragonolobus

Winged bean

Edible. Climbing. Does best in hot, humid areas. Drought and

sandy soil sensitive.

Pueraria phaseoloides

Tropical kudzu

Green manure cover or pasture crop. Tolerates high water levels,

acid soils and dry season. Grows well under trees. Not to be

confused with the weedy Pueraria lobata.

Vigna unguiculata

Forage cowpea

Green manure/cover crop. Drought tolerant but for well-drained

soils. Bushy.

54 Chapter 3

problem. Mulching can be an alternative, but it is normally expensive to spread

out in the orchard. Straw, hay, dried grass, wood shavings or any cheap and

easily obtained organic material can be used (Fig. 3.7a). Care has to be taken

to not let the mulch come in close contact with the trunks to avoid excess

moisture and collar rot occurring. Mulch will prevent weeds from growing and

at the same time will allow roots to grow near the surface, where the soil is of

better quality. One problem with mulch if allowed to dry out is a possible risk

of ﬁ res and it can harbour rodent pests. Plastic mulches can be used, especially

in short-lived crops like papaya or pineapple, and their use will be determined

by the economic convenience (Fig. 3.7b). Normally only the plant rows are

mulched, and sometimes just a piece of black polyethylene about 1 m square is

placed around the tree pole to avoid the initial direct weed competition.

No vegetation on the orchard ﬂ oor ﬁ ts better in orchards located in arid

zones like the Peruvian coast or the Florida coralline sands. In desert areas,

there is very little to do to control weeds if drip irrigation is used. In Florida,

herbicides are used after rains to control weeds (see next section). The no-

vegetation approach means no competition with the crop for water or nutrients.

It also allows easier incorporation of manure or cover crops into the soil.

WEED CONTROL

Weeds, as well as associated crops, compete with the fruit trees for water and

nutrients, and in certain circumstances can be an important factor in lowering

(a) (b)

Fig. 3.7. Weed control can be achieved by placing organic mulch under the

trees (a), or plastic mulch (b) is also used on shorter-cycle crops or during tree

establishment.

Cultivation 55

crop yields. For example, neglect of weeding results in a 20–40% decrease in

pineapple yields. In situations with adequate moisture in the soils, weeds are

not a factor in competing with the crop for water. Some weeds can also cause

sanitary problems that can a ect the crop, this in addition to the negative

aesthetic aspect. Weeds are an important problem in climates where there

are year-round crop-growing temperatures that favour continuous growth.

This weed problem is especially acute in tropical and subtropical climates,

except for subtropics with cooler winters, or the arid tropics and subtropics.

Weed control is particularly troublesome during the ﬁ rst 2–3 years of orchard

establishment, when the trees have not yet developed substantial canopies to

shade weed growth.

In arid areas with drip irrigation and little or no rainfall, weed problems

are not very di cult to solve, since weeds will only be found in wet areas

around a dripper and these can be eliminated mechanically or chemically.

However, if sprinkler, furrow or basin irrigation is used, weeds will be

widespread and control measures will have to be used frequently. Weeds can

be controlled by non-chemical and chemical means. Both approaches have

advantages and disadvantages, but if done properly can produce similar

results. The approaches can also be combined. The non-chemical control

involves either weed elimination or cutting weeds back to reduce competition.

Annual weeds are controlled by the use of hoes, pulling them manually,

ﬂ ooding the land, the use of mulches, and mechanical tilling or discing the

soil. Mechanical cultivation should be avoided, though very e ective, due to

the damage it causes to the superﬁ cial feeder roots. Weed height reduction

is achieved by periodically cutting the weeds back with a machete and with

mowers or many types of brush cutters.

The chemical approach relies on herbicides or weed killers, which can

belong to di erent chemical groups. Herbicides can be selective and non-

selective; in both categories some are for foliar application and others for

soil application: The chemicals can work by contact or can be translocated

to other parts of the plant (systemic). Contact herbicides kill only the tissue

that they contact, while the systemic herbicides applied to the soil or the

foliage will be absorbed by the roots or aerial parts and move into the plant,

reaching the places where they will have their lethal e ect. Some herbicides

are applied to the soil before the weed seeds germinate and thus are called pre-

emergence, while the post-emergence herbicides are applied once the plant

has germinated. Pre-emergence application, either before or immediately after

planting, is e ective, the least costly and a desirable management practice.

Some of the techniques used for chemical weed control consist of using

a contact herbicide for annual weeds and a systemic herbicide for perennial

weeds. Sometimes a pre-emergence herbicide can be used before the start of the

rainy season. Several herbicides are on the market and di erent approaches for

their use can be taken. An analysis should be made to be sure about the most

convenient application procedure. Annual weeds should be eliminated when

56 Chapter 3

they are succulent and before they shed their seeds; the same is true for biennial

weeds. With perennial weeds the approach has to be di erent, and normally they

will be much harder to control. Chemicals are applied with spray apparatus,

which ranges from simple knapsack sprayers to the more sophisticated boom-

type sprayers, and some products are incorporated in dry form into the soil.

In young orchards care has to be taken not to use certain herbicidal

products that can check tree growth by being absorbed through the root system.

In other cases, the small trees have to be protected from receiving the chemical

spray or drift, which can be absorbed by the green stem, branches and leaves

or cause severe burns in these young tissues, while in large trees this is not

normally a problem because of their woody bark. For young seedlings and newly

transplanted orchards, glyphosate, a systemic herbicide, may be applied by rope

wick or weed wipers saturated with a more concentrated herbicide solution and

wiped on the weed leaves. These applicators eliminate spray drift and can be

used close to the stem. Application of herbicides through the irrigation system,

known as herbigation, has been shown to be e ective. An important aspect

with many herbicides is to know the time needed after application for them to

be absorbed; in many cases if it rains too soon after application, the product

will not have had a chance to be absorbed and it might be lost. Often morning

applications are done to avoid the afternoon and evening rains.

There are restrictions on herbicide use imposed by manufacturers and

government agencies, and all applicators must know the proper uses. Growers

who intend to export fruit should become acquainted with regulations of the

consuming countries governing the use of registered chemicals, residue levels

and other precautions. In organic production, no chemical herbicides are

normally allowed and only mechanical or cultural practices like cover crops or

mulching can be used.

The use of herbicides can be expensive, so a cost comparison has to

be made between spraying them over the whole surface and the system of

mowing between rows and cutting weeds back in the row with a machete or

the use of a hoe, or the mixed chemical–mechanical approach of applying a

herbicide in the rows and mowing between them. The mixed approach keeps

tree rows free of weeds using mulches or herbicides, or weed growth is kept in

check by hoeing or keeping weeds low with a machete or mowers. In the humid

tropics, the area between rows has either a legume or grass that is mowed

periodically. The approach used is a ﬁ nancial decision and will depend on

the orchard size and ﬁ nancial status of the grower. Weeding is an important

production cost component in orchard maintenance.

WIND BARRIERS

Wind can have several e ects on fruit crops. Gentle winds help ventilate the

orchard and create a healthier atmosphere around the trees. They will also

Cultivation 57

favour wind pollination and fecundation. However, strong winds can produce

mechanical damage and, depending on velocity, can have severe, sometimes

even fatal, e ects on crops, resulting in uprooting the whole tree, broken main

trunks, broken sca old branches or dehydrated and burnt leaves to completely

defoliated trees. Hurricanes or cyclones during ﬂ owering and fruiting periods

can cause a severe ﬂ ower and fruit drop in many species. Bananas and

plantains are some of the most susceptible crops to wind damage. In Central

America, bananas and plantains are sometimes subjected to blow down

caused by gusts of wind that unexpectedly hit certain areas and break all tall

pseudostems, and a whole year’s production is lost until the ratoon pseudostem

grows and harvesting can resume. Windbreaks are especially helpful when

normal prevailing winds become gusty with velocities exceeding 65 km/h.

Occasional high-velocity winds are damaging to orchard trees, but equally

harmful in the long run are the mild prevailing winds of 40–50 km/h. Trees

exposed constantly to such prevailing winds gradually develop a deformed,

lopsided shape, with all branches growing away from the winds.

Winds can also a ect sprinkler irrigation and spraying operations, causing

uneven water distribution of herbicides and other chemicals, which can drift

on to other plants. It is necessary to protect the plantation with a barrier that

should be e ective ideally from planting. Wind barriers will reduce water loss

from the soil and leaves, produce a more uniform temperature in the orchard

and reduce wind erosion (Wilkinson and Elevitch, 2000). The windbreak can

reduce crop evaporation on the leeward side to 40% within twice the height

of the windbreak, being more e ective at higher wind speeds (Fig. 3.8a).

The reduction in evaporation allows the trees in the orchard to develop the

higher humidity in the canopy that is important for crops such as rambutan,

mangosteen and durian. Sometimes a partial solution can be to plant the tree

rows following the same direction of the main winds, so that the ﬁ rst trees in

the rows protect the rest of the row.

Two types of barriers are used: natural (Fig. 3.8b) and artiﬁ cial (Fig.

3.8c). Both should ﬁ lter, not stop, the wind and have about 50% permeability.

The windbreaks are perpendicular to the prevailing wind direction and

extend beyond the width of the orchard so that no wind enters from the

sides. Natural barriers consist of two or three rows of trees. The e ectiveness

of the windbreak depends upon the height and lateral extent of the barrier,

its permeability and the angle of incidence of the wind to the barrier. Wind

velocity is reduced to 35% within a distance of four times the height of the

windbreak (Fig. 3.8a).

Many di erent species are used as windbreaks, which complement each

other in size, growth form and canopy height. Sometimes a single species is

used. All trees used as a windbreak should compete as little as possible with

the crop; therefore deep-rooted and well-anchored, ﬂ exible trees are preferred.

The trees should be adapted to the zone and should not harbour enemies of

the crop (Table 3.5). Ideally the barrier should be planted before the crop so

58 Chapter 3

that it starts protecting it from the beginning. Barriers have to be maintained,

and yearly pruning is usually performed to avoid too much compactness; also

subsoiling hook should be passed 3 m away from the barrier to avoid excessive

root competition with the crop. Barriers of trees that produce fruit instead of

timber or ﬁ rewood can be used. The main disadvantages of natural barriers

are that they take time to be e ective, use up land and compete with the crop

for light, water and nutrients. They also need maintenance and can harbour

crop enemies.

Few windbreak trees can provide crop protection under hurricane

(typhoon) wind velocities. One of the most substantial windbreak trees is

Garcinia spicata, called ‘Fukugi’ in Okinawa, Japan. Windbreaks composed of

this species have been observed to withstand hurricane winds of approximately

210 km/h in northern Okinawa, providing crop protection without itself being

damaged. This species is related to mangosteen and grows well in subtropical

and tropical climates. Its only drawback is the very slow growth rate.

Artiﬁ cial barriers are usually plastic fabric with 30–70% permeability to

wind (Fig. 3.8c). They should be resistant to ultraviolet rays as well as to sun

and rain, and resist deformation. Good barrier materials should last 10–15

years. The main advantage is that they can be installed and start functioning

immediately. Additional advantages include that the permeability can be

chosen and it will remain the same over the lifetime; they do not use much

space or compete with the crop and do not harbour plant enemies; they

can be moved to another location if necessary, and they do not need any

maintenance. Their main disadvantage is the high initial installation cost.

100

(a) (b)

(c)

Wind

direction

Wind velocity (%)

–10 –5 0 5

Distance – multiple of windbreak height

10 15 20 25 30

Fig. 3.8. Windbreaks reduce tree damage by reducing the wind velocity on both

sides of the barrier (a), with a signiﬁ cant reduction on the leeward side up to ten

times the height of the windbreak. Trees can be hedged (b), as in this kiwi orchard,

or an artiﬁ cial barrier can be made with plastic netting (c), as in this carambola

orchard.

Cultivation 59

Table 3.5. Some trees for windbreaks. Adapted from Wilkinson and Elevitch (2000).

< 6 m

Annona muricata Acacia koaia Averrhoa carambola

Bixa orellana Cassia spectabilis Casuarina equisetifolia

Citrus reticulata Coccoloba uvifera Eugenia uniflora

Gliricidia sepium Leucaena leucocephala Morus nigra

Myrciaria cauliflora Parkinsonia aculeata Pimenta dioica

Psidium guajava Psidium cattleyanum Sesbania sesban

Thepesia populnea

6–15 m

Anacardium occidentale Acacia confusa Albizzia lebbeck

Artocarpus integer Azadirachta indica Bambusa oldhamii

Casimiroa edulis Cassia (Senna) siamea Casuarina cuninghamiana

Cedrella odorata Chrysophyllum cainito Cojoba arborea

Cordia subcordata Cordia egalantha Dalbergia glomerata

Dimocarpus longan Erythrina berteroana Erythrina poeppingiana

Grevillea robusta Ilex tectonica Intsia bijuga

Khaya ivorensis Macadamia integrifolia Mammea americana

Manilkara zapota Melia azedarach Musa balbisiana

Pandanus odoratissimus Pithecellobium dulce Pouteria campechiana

Schinus molle Syzygium aromaticum Syzygium malaccense

Tabebuia pentaphylla Tamarindus indica Terminalia superba

>16 m

Acacia auriculiformis Acacia koa Acacia mangium

Acrocarpus fraxinifolius Aleurites moluccana Artocarpus heterophyllus

Artocarpus altilis Azadirachta excelsa Calophyllum inophyllum

Cocos nucifera Dendrocalamus asper Eucalyptus dunnii

Eucalyptus microcorys Guadua angustifolia Litchi chinensis

Mangifera indica Pinus caribaea Prosopis pallida

Pterocarpus indicus Sandoricum koetjape Swietenia macrophylla

Syzygium jambos Terminalia catappa Tristania conferta

60 Chapter 3

PEST BARRIERS

In some tropical areas, birds and fruit bats can cause extensive losses of fruit

near harvest. Numerous bird species, from solitary species to large ﬂ ocks

of parrots, will eat fruit. Various approaches are used to reduce these losses,

including propane-ﬁ red cannons to scare the birds and permanent net

enclosures (Fig. 3.9). The propane-ﬁ red cannons produce loud, unexpected

blasts at random intervals, which are generally not less than 3 min apart.

The noise keeps the birds nervous, while they will become accustomed to

cannons that are always located in the same spot in a ﬁ eld, if the ﬁ rings occur

at regular intervals or ﬁ re very rapidly. Other electronic devices produce

electronic synthetic sounds to repel birds by reproducing distress calls that

mimic individual bird species. Visual repellents, such as balloons, streamers

and ﬂ ashing lights, are not as e ective as acoustical devices. Bird netting is

available that is lightweight and draped over the tree and, once over, harvest-

ing is possible, to heavier, ultraviolet-resistant protective materials fastened

to an overhead structure that totally encloses the orchard. The overhead

structure has a very high initial cost. Netting comes as rigid or stretch

materials in di erent widths and mesh sizes. The material chosen depends

upon the crop and layout, expected material life and the equipment available

for installation and removal.

In Asia, structures are built and covered with ﬁ ne nylon mesh to exclude

aphids that carry viral diseases. An example would be a mesh structure in

which papaya is grown to protect it from ringspot virus. These structures

cover hectares of land and are rather light in structure and frequently su er

considerable damage from hurricanes (typhoons) during the warm season.

(a) (b)

Fig. 3.9. Birds and fruit bats cause signiﬁ cant damage to fruit and may require the

use of a protected shelter to protect the crop (a). Protective shelters are also used

to protect papaya and other crops from insect-borne viruses (b); these lightweight

shelters are made of very ﬁ ne mesh nylon.

Cultivation 61

FURTHER READING

Chandler, W.H. (1958) Evergreen Orchards. Lea and Febiger, Philadelphia, Pennsyl-

vania.

Choudhury, J.K. (1963) Early bearing of guava by photoperiodic induction. Science and

Culture 29, 213–214.

Coronel, R.E. (1983) Promising Fruits of the Philippines. College of Agriculture, University

of the Philippines at Los Baños, Laguna, Philippines.

Morton, J.F. (1987) Fruits of Warm Climates. J. Morton, Miami, Florida.

Popenoe, W. (1974) Manual of Tropical and Subtropical Fruits. Facsimile of the original

1920 edition, Hafner Press, New York.

Samson, J.A. (1986) Tropical Fruits, 2nd edition. Longman, New York.

Tomlinson, P.B. (1987) Architecture of tropical plants. Annual Review of Ecology

Systematics 18, 1–21.

62 © CAB International 2011. Tropical Fruits, 2nd Edition, Volume 1

(R.E. Paull and O. Duarte)

TREE MANAGEMENT

INTRODUCTION

Tree management plays a key role in the economic success of an orchard. The

soil and climate conditions chosen for the species and the variety to be grown

set the foundation for an orchard. The infrastructure and associated logistics,

such as packing and storage facilities, coupled to adequate transportation,

energy availability, and water quality and supply, will aid in continued success.

Tree management can compensate for less than ideal soil or climate conditions

and the opposite is also true; improper tree management can render the best

soil and climate conditions of little value.

Tree management includes, ﬁ rstly, the choice of propagation material that

is of the highest quality. Other components of tree management are irrigation,

pruning, fertilization, pest and disease control, pollination, ﬂ ower and fruit

thinning, fruit bagging and the use of plant growth regulators. All these

components together will result in a proper-functioning tree that will produce

good yields and fruit quality.

A frequent problem is that some growers will attempt to apply very

sophisticated management practices without being aware of their advantages

and limitations. Some management practices apply only to certain varieties

or only under speciﬁ c conditions. Other growers will use plant growth

regulators without having adequate irrigation or fertilization procedures. It

is crucial to solve these basic management practices before attempting more

reﬁ ned practices. We have seen a number of cases when prospective growers

will spend a lot of money in preparing the land and installing an expensive

irrigation system and then buy poor-quality plants for their orchard. Other

problems are experienced with the purchase of a bad piece of land just because

it is cheap and then believing that you will get maximum yields, or hiring

poorly trained ﬁ eld supervisors and/or failing to provide adequate supervision

and training of labour while sophisticated practices are being applied. These

decisions are short-sighted and frequently lead to poor fruit yields and quality.

Tree Management 63

PROPAGATION

Probably most fruits sold and consumed a few centuries ago would have

been rated as poor in quality by present standards. Fruit size, colour, ﬂ avour,

appearance and postharvest handling have dramatically improved, while the

levels of defects, disease and pest damage have declined, especially in the last

half-century. Commercial production a few centuries ago, when most people

lived in rural areas, was based upon backyard or small orchard production,

frequently of plant material that had received limited selection. Initially, the

seed from a selection of the best type was planted, which frequently did not

ensure the maintenance of the desired selected characters, though it is an

easy approach. Large orchards cannot rely on highly variable plant material if

they want high yield and consistent fruit quality. Higher quality was achieved

by selecting superior wild trees or chance seedlings, and these genotypes were

propagated, often as vegetative materials. The use of vegetative material meant

that the genetic characteristics of these desired plants were retained and led

to the creation of varieties or cultivars. At the same time, especially in the

temperate zones, growers, nurserymen and hobbyists were ﬁ nding new types

of plants that arose either as chance seedlings or as mutations, which they

selected and evaluated. Later, fruit-growing specialists and entire institutions

started breeding programmes that initially consisted of sowing numerous

seeds to see if some of the seedlings were better than their parents. In many

cases, nurseries or growers found mutants that were superior or had a special

characteristic. Superior plants known to exist elsewhere were asexually

propagated. Examples include the ‘Fuerte’ avocado, which was brought to

California as scions from Mexico; the ‘Washington’ navel orange, discovered

as a mutation in Brazil and its buds taken to the USA, where it was popularized

and later spread all over the world; the ‘Smooth Cayenne’ pineapple, discovered

in South America and taken to Hawaii; and the ‘Solo’ type of papaya,

discovered in Barbados and also taken to Hawaii. Many tropical fruit breeding

programmes that use modern techniques, such as mutation induction and

hybridization, to obtain superior varieties exist around the world.

Propagation of new selected cultivars is more sophisticated and relies

mainly on asexually propagating certiﬁ ed varieties. The pineapple canning

industry relies especially on selection out of the ‘Smooth Cayenne’ variety,

while the pineapple fresh fruit export industry is dominated by the ‘Smooth

Cayenne’ low-acid hybrids. Five or six major mango varieties are the backbone

of the export trade, and the avocado varieties in international trade are ‘Hass’

and ‘Fuerte’. The international trade in bananas is based on one variety,

‘Grand Nain’, in the Cavendish group.

Many fruit trees need a rootstock that is adapted to adverse soil conditions

and has resistance to certain diseases, nematodes and insects. The rootstock

can also be required to attain a certain plant vigour, to achieve this the variety

64 Chapter 4

will have to be budded or grafted onto the desired type. The rootstock may

have di erent vigour or simply will provide a root for a species or variety that is

di cult to root by cuttings or air layers.

Certiﬁ ed planting material is meant to ensure that the desired variety is

being obtained and it is free of speciﬁ c diseases. Care needs to be taken that

the planting material purchased is free of pests, nematodes and diseases that

could contaminate areas where these problems do not exist.

Main propagation methods

Sexual or seed propagation

Propagation by seed is regarded as the most ‘natural’, but frequently the

new plants are not identical to the mother plant and thus variability occurs.

The only seed-propagated plants that are identical to their mother plants are

those that have been self-fertilized for several generations so that the genetic

arrangement has become uniform (homozygous), and they are called pure

lines, such as rice or wheat varieties. This seldom happens with fruit trees,

which are mostly cross-pollinated and show variability when propagated by

seeds.

In some species, the seed is exactly the same as the mother plant. The

condition is called apomixes, where an embryo develops in the absence of

fertilization by pollen. Apomictic seeds occur in mangosteen, achachairu and

jaboticaba, with vegetative embryos and no sexual embryo being present in

the seed. Mango varieties of the Indochina–Philippine group (see Fig. 10.5)

and most citrus species’ seeds also have a sexual embryo, and several embryos

can arise from the nucellar tissue of the ovary that surrounds the embryo

sac. Where you have embryos from nucellar tissue, often the sexual embryo

is suppressed by these surrounding asexual embryos. These propagation

methods are considered clonal, with seeds being used.

Seeds are used commercially to propagate herbaceous, short-lived crops

such as papaya, cocona, naranjilla, tree tomato, yellow and purple passion

fruit, giant passion fruit, sweet granadilla, banana passion fruit, cape goose-

berry and some others, such as coconut and pejibaye palm (Bactris gassipaes).

Variability is very low since the crops are very homogeneous and the best fruits

are selected to obtain seed. In the case of papaya, hybrids, a cross between two

selected parents or a selected variety like ‘Maradol’ and ‘Kapoho’ are used.

For selected varieties, hermaphrodite plants are self-fertilized to obtain the

same variety.

The other important use of seeds in fruit crop production is to obtain

rootstocks on to which the commercial varieties will be budded or grafted.

Normally seeds for rootstocks are highly variable, leading to the propagation of

rootstocks by cuttings or layers so that they are genetically identical and there

is no variability in the orchard. Rootstocks derived from apomictic embryos are

genetically identical to the mother plants.

Tree Management 65

For many lesser-known tropical fruit trees, seed is used for propagation

because they do not have a high commercial value and little information exists

about asexual propagation. The consequence is that fruits are very variable

in quality and are not easily marketed. If the quality of these fruit is to be

improved, methods to propagate them vegetatively are needed.

Asexual or vegetative propagation

When a new plant is regenerated or propagated from a piece or part of a

mother plant, it is called clonal or vegetative propagation. Plants can be

vegetatively propagated using many di erent tissues from roots (breadfruit)

(Fig. 4.1a), stem cuttings (guava), apices (banana) and buds (citrus) (Table

4.1).

(a) (b)

Fig. 4.1. Asexual propagation includes the use of root cuttings for breadfruit (a),

tissue culture (b), budding (c) and the use of suckers for pineapple (d).

66 Chapter 4

Table 4.1. Propagation methods commonly used for selected tropical fruit crops

(Garner and Chaudhri, 1976).

Crop Seed

Suckers

Stooling

Layering

(Marcotting) Cuttings

Grafting

Budding

Annona Air layers Stem Budded,

grafted

Avocado Grafting

Banana Corm

Breadfruit Root

Carambola Budded

Durian Seed Air layers Stem Budded

Guava Air layers Stem and

root

Budded

Jackfruit Air layers Stem Budded

Lanson, duku,

langsat

Seed Budded

Litchi and longan Air layers Budded

Mango Polyembryony Air layers Stem Budded

Mangosteen Apomixis Stem Grafting

Papaya Seed Stem Cleft

grafting

Passion fruit Seed Air layers Stem

Pineapple Crown and

shoot

Leaf and

bud

Rambutan Air layers Budded

Sapodilla Air layers Stem Budded

approach

Cuttings

A leafy cutting is normally the terminal or subterminal part of a shoot

with leaves left. A terminal cutting comprises the tip of a shoot, while the

subterminal comprises the portion just below the tip of a branch; the upper

leaves are left on and the basal leaves removed. These cuttings are held under

conditions that prevent water loss (hermetic polyethylene chambers or a

mist bed) in some porous medium with good drainage and moisture-holding

capacity. Cuttings can be used for many tropical fruits, including guava,

cashew, acerola, jaboticaba, golden spoon, litchi and passion fruits. When

propagating hardwood or semi-hardwood cuttings, all the leaves are removed

or absent, as for Spondias.

Most stem cuttings are treated with compounds that have auxin-like

activity, such as naphthalene acetic acid (NAA) and/or indole butyric acid

(IBA), to improve rooting percentage, accelerate the rooting process or to obtain

more roots per cutting. The rooting products are applied to the basal cut end as

prepared powders or in liquid form (50% alcohol/50% water) at concentrations

of 1000 to 10,000 ppm, depending on the species, variety and type of cutting.

Tree Management 67

Tissue culture

This approach (in vitro propagation) uses micro-cuttings, which can be

meristems or portions of cells from di erent parts of the plant (Fig. 4.1b). The

process involves two phenomena: dedi erentiation from its original tissue

condition to callus, followed by redi erentiation to generate all the tissues of a

whole plant, which involves somatic embryogenesis. In many crops and under

certain tissue culture protocols, somaclonal variations can be a problem.

Somaclonal variation is thought to be due to DNA changes in the cell nucleus

caused by tissue culture stress in the presence of plant growth regulators such

as auxin and cytokinin.

This in vitro approach is used for rapid and consistent reproduction of elite

or di cult-to-propagate genotypes. Since the tissues are so small and tender,

they are very prone to rot or infection, and therefore they are ﬁ rst surface-

sterilized then handled under sterile conditions in special growth chambers.

During the last three or four decades, several species have been propagated by

this system to ensure freedom of diseases and true-to-type plants. The cost per

plant is normally higher than asexually propagated plants, but many plants

can be generated quickly from one elite mother plant.

Until now, soft-tissue plants like pineapple, papaya, banana and plantain

have been commercially produced, while with trees some success has been

obtained with avocado, mango, Annonas and jackfruit. This propagation

method is essential if molecular biology gene transfer approaches are to be

used for tropical fruit tree improvement.

Layering

In layering a portion of a branch relatively close to the tip and still attached

to the tree is put in contact with a moist substrate and the stem below the

substrate is cinctured. New roots emerge into the medium, then the branch

portion with the new roots is separated from the mother plant, cutting below

the roots, and a new plant is obtained.

The most popular layering system for tropical fruit trees is air-layering or

marcottage. The leaves are removed from a portion of a branch located about

30–60 cm from the tip and a 3 cm ring of bark peeled o . The girdled area and

part of the stem with bark remaining are covered with a ball of moist sawdust

or peat moss. The ball is wrapped tightly with plastic sheet or aluminium

foil. Sometimes auxins can improve the rooting of these air layers. After 1–3

months, when the roots are visible and have turned from a white to cream

colour, the air layer can be harvested by cutting below the new rooted area.

The wrap is removed and the ball with roots transplanted into a pot or bag with

a substrate and held under medium shade. When this new plant shows signs

of growth, the bag or pot can be taken into full sun for some months until an

adequate size is attained for transplanting to the ﬁ eld. Air-layered plants lack a

tap root and can be more easily blown over by strong winds, the same as plants

propagated by cuttings, but this is not a problem under normal ﬁ eld conditions.

68 Chapter 4

Grafting or budding

Grafting is a system where a piece of stem containing two to six buds, called

a scion, is used, while in budding just a single, detached bud is joined with

the stem of a plant that provides the root system (Fig. 4.1c). The plant that

provides the root system is called the rootstock. The bud or stem piece with the

buds (scion) is of the variety that will become the tree canopy.

The most common methods of grafting are cleft, splice (whip), side and

saddle graft, while the main budding methods are ‘T’ or shield, patch, chip

and veneer. In some cases, branches of di erent trees are brought in contact to

form a union, and this is called approach grafting. For grafting or budding to

be successful, the cambium layers of both components have to be in intimate

contact to regenerate the union with all needed parts: xylem, phloem and

cambium. Many tropical fruits are, or can be, propagated by this system, and

most of them will do well with di erent grafting or budding methods. Some

species are more di cult and a speciﬁ c type of grafting or budding has to be

used. The skill and experience of the grafter plays a very important role as to

which method is best for certain species, while in other species several methods

will produce satisfactory results.

Every grafted or budded plant has two genotypes, that of the root system

(rootstock or stock) and that of the canopy (variety or scion). The orchard

canopies should be genetically identical because the buds are taken from a

tree or trees of the same variety, so they are cloned on di erent root systems.

The ideal would be for the roots to be from a single clone, which occurs when

they are from vegetatively propagated plants or come from seeds with nucellar

embryos because of their asexual origin (apomixis). In most other fruit trees,

the seedlings used for rootstocks are of sexual origin so they vary among

themselves. Since the rootstock can signiﬁ cantly inﬂ uence the canopy growth

and development, any variation can show up once planted in the ﬁ eld. The

root and canopy maintain their original genetic make-up and do not exchange

genes, except in the few cells around the graft union.

Natural propagative structures

Plants produce organs or structures that are used for its propagation (Table

4.1). Examples of these structures would include runners in strawberry

and suckers in date palms. Some tropical fruits do produce suckers. Banana

or plantain suckers have a solid base called a corm. This corm is the normal

propagation material for these species. The sucker arises from the corm of the

mother plant and can be transplanted whole or with most of the pseudostem

removed, leaving the base and the corm. This piece is buried ~10 cm deep.

Pineapple suckers arise on top of the fruit (crown sucker), at the base of the

fruit (slips) and at the base of the plant (basal sucker) (Fig. 4.1d). The preferred

propagation material is the sucker at the base of the fruit, but they are not

produced all year round by the plants. These suckers are detached from the

Tree Management 69

mother plant and left to dry for a few days so that the wound forms its scar,

and after that they can be used for a new pineapple planting.

Differences between sexually and asexually propagated

fruit trees

Trees originating from seeds tend to be vigorous since they are in a juvenile

state that does not produce ﬂ owers and fruits. After these plants reach a

certain age and become adults, they are able to ﬂ ower and fruit. For some

fruit trees the juvenile period can last 8–10 years. During this juvenile period,

the plant will grow vigorously and become very large unless subjected to

modern tree management practices. Additionally, trees from sexual seeds are

normally genetically di erent from their mothers and among themselves, and

potentially have di erent growth patterns and have fruit of di erent quality

characteristics, making marketing more di cult.

Asexually propagated trees are clones of their mother plants and bear the

same type of fruit. Additionally, the material used for asexual propagation is

normally obtained from a plant in the adult phase, not in the juvenile phase.

This adult material will have already fruited and its quality can be evaluated.

The trees obtained from adult plants will ﬂ ower and fruit upon receiving the

external signal that induces ﬂ ower development and will not have a juvenile

phase such as a plant from seed. If no external stimulus is required, they will

ﬂ ower immediately. This earlier ﬂ owering results in smaller trees. In the case

of grafting or budding, the existence of a graft or bud union can restrict the

internal xylem and phloem transport and additionally inﬂ uence tree size

reduction and precocity. Dwarﬁ ng rootstocks are being sought for species that

normally grow very large.

NURSERY TREE MANAGEMENT AND PLANTING

Tree management starts in the nursery, since many problems in fruit

production can be avoided by just taking care of this phase of development.

Seedlings

At this stage many trees will show twisted or malformed roots or stems due

to the position of the embryo at sowing time. In some species this can be

controlled or reduced by sowing the seed in the correct position. This is

unpractical with some species because of the small seed size, and when the

seeds are polyembryonic (citrus, mango) the orientation of some of the

embryos, relative to the correct position of the seed at sowing, is not normal,

70 Chapter 4

and there will be a number of seedlings that come out with a swan-neck-

shaped stem base or root. Seedlings with this condition should be discarded

since they do not become good plants or rootstocks. Only seedlings with

straight stems and roots should be transplanted to the nursery pots or bags.

Plants in nursery containers

Plants left too long in nursery pots or bags normally have deformed root

systems. The main root will reach the bottom of the container and will not

be able to grow through so it will bend and start growing horizontally in a

circular fashion, following the lower rim form of the container. The lateral

roots, upon reaching the walls of the container, will grow around the root

ball and form a sort of peripheral basket or root mesh (see Fig. 3.5b). This

condition is also referred to as root-bound. When transplanted, the root-ball

prevents the development of a good root structure; the plants remain stunted

and are poorly anchored in the soil. Therefore only plants that are not root-

bound or have not stayed in the container too long should be selected and

planted.

Transplanting in the nursery into larger or taller containers that allow

the roots more time before they become deformed is preferable. If planting

material of the desired variety is in short supply, then the deformed plants can

be used. Remove the deformed plant from the container and cut the main root

above the point where it started to bend at the bottom. The lateral roots should

also be cut to disrupt the peripheral root basket, if present, by making several

vertical cuts on the outer part of the root-ball.

Planting

Planting in warm climates can be done almost any time of the year. If the

weather is too cool, planting can be delayed. If no irrigation is available,

planting should be done at the beginning of the rainy season. Some people

recommend adding 20–50 g triple superphosphate in the bottom of the hole,

separated by a 3–5 cm layer of soil from the root-ball.

PRUNING

Pruning fruit trees involves training the tree to the desired shape. The shape of

the trees will depend upon the species and the speciﬁ c management objective.

Several models that are based upon developmental fate of the apices, the

conﬁ guration of the branching points and plagiotropy (horizontal growth)

and orthotropy (vertical growth) of tree axes exist. The growth of the trunk

can be monopodial, rhythmic and indeterminate.

Tree Management 71

The models of tree growth habits provide a basis for comparing pruning

and training protocols for di erent tropical fruit trees. Pruning to shape a

tree aims to control the number, orientation, size and angle of branches

and thereby improve the trees’ structural strength to carry a fruit load,

reduce wind damage, increase light penetration, improve air circulation,

stimulate ﬂ ower-shoot development and enhance fruit yield and quality. Too

much pruning can delay ﬂ owering and lead to vegetative growth. Pruning

is not practised in monoaxial crops with short life cycles (banana, plantain,

pineapple and papaya), except that excess suckers are removed in bananas

and plantains; in papayas normally short lateral branches arising from the

main stem are removed. Broken, weak, drooping and diseased branches and

leaves should be removed. Pruning of many tropical trees may reduce yields

during the following season (mango, litchi), but some form of tree size control

is necessary to maintain a manageable tree size and structure. The trend is to

maintain the trees at a 3–5 m height by yearly or more frequent pruning for

ease of ﬂ ower cycling, pruning and harvesting.

Avocados, mango and litchi have monopodial rhythmic growth (Table

4.2). In avocado, the branches are morphologically identical to the main

trunk, with ﬂ owers borne laterally with only minor e ects on the vegetative

shoot. In the case of guava, mango and rambutan, the rhythmic ﬂ ushing

of vegetative growth and ﬂ owering inﬂ uences when and how pruning is

carried out. Flowers develop on shoots that are not ﬂ ushing, and the objective

of pruning should be to increase the number of shoots that can ﬂ ower

simultaneously. Carambola can be extensively pruned to remove overlapping

branches and topped to maintain 2–4 m height without signiﬁ cantly reducing

yield, and it can also be trellised.

In the past, it was said that only deciduous fruit trees had to be pruned;

nowadays most of the evergreen tropical trees are being pruned in modern

orchards. Normally there has to be a formation pruning at the beginning

of the plantation, and later production and sanitary pruning has to be

performed.

Formation pruning

This practice is of major importance in deciduous fruit trees, where it takes

several cycles to achieve the desired form. Most tropical fruit species have a

natural tendency to develop a desired form, but often they need to be helped to

achieve well-balanced and anatomically proportioned canopies. This canopy

should be not too tall, without structural faults that might cause the trees

or main branches to break easily with a full fruit load. The object is to prune

the trees to achieve the right form and avoid overcrowding of branches in the

canopy. The main pruning actions eliminate all shoots arising below the graft

union. Shoots below the graft union can lead to a loss of a grafted canopy as

72 Chapter 4

Table 4.2. Tropical seedling fruit tree growth is normally continuous and the trees develop different growth phenomenon and branching

habits. Flowering then either becomes synchronized to vegetative growth or is more responsive to the environment (Verheij, 1986).

Branching Vegetative growth and ﬂ owering Example Growth characteristics

Single-stemmed

(monoaxial)

Continuous Concurrent Papaya, coconut Constant growth and concurrent ﬂ oral development,

stable number of leaves thus a constant top to root

ratio. Improvement via altered growing techniques

(nutrients, water) to maintain high growth rate.

Terminal Banana, pineapple Supported by current photosynthesis. Suboptimal

growing conditions postpone ﬂ owering.

Improvement via altered growing techniques

(nutrients, water) to maintain high growth rate.

Equidistant planting patterns frequently used in

single or double row.

Branched

(polyaxial)

Flushes Concurrent Passionﬂ ower Rapid, continuous shoot growth and concurrent

ﬂ owering, rectangular planting patterns.

Separate in loci Avocado, durian, mango,

Annona spp., soursop,

jackfruit, abiu, lanson

Rhythmic growth. Major competition between

intermittent vegetative growth and ﬂ owering.

Synchronous vegetative growth with almost

simultaneous ﬂ owering and fruiting, feedback

control between top and roots to maintain balance.

External stimulus for ﬂ owering and growth rhythm.

Improvement by manipulation of tree (juvenility

reduction, pruning, fruit thinning, girdling,

defoliation) before growing conditions (nutrients,

water) have favourable response.

Separate in time Atemoya, avocado,

mango, mangosteen,

litchi, carambola,

rambutan, guava, longan,

chiku

Feedback control between top and root growth.

Improvement in yield via manipulation of the

tree using pruning, fertilization and irrigation.

Improvement as for separate in loci category above.

Tree Management 73

these shoots can grow taller and more vigorously than the grafted canopy.

Another objective is to eliminate all excessive primary branches and all water

sprouts that are very vigorous and succulent shoots in a juvenile stage that

will take time to become adult branches.

The modern tendency is to have canopies close to the ground. In the case

of trees that tend to have a main stem with vigorous upright growth, they

are tipped at about 80–90 cm in order to induce lateral branching that starts

below that point and close to the ground (Fig. 4.2a). If the branching starts

higher on the main stem, as in non-pruned trees, the canopy will leave too

much empty space between the canopy and the ground. This space is wasted

and results in a higher tree, and it is more di cult to carry out spraying,

fertilization, pruning and harvesting.

Once the tree has been tipped, several lateral branches will develop.

Three to four of these lateral branches are retained to become the main

sca olds of the tree (Fig. 4.2b). The lateral branches are selected so as to

form a glass shape, with a 120 or 90° angle between the third and fourth

branches (Fig. 4.2c). The branches should not arise too close to each other

on the main stem, with 20–30 cm between them or between at least of one

of them and the other two branches. If all the main lateral branches come out

too close together on the main stem, too much of the canopy weight will be

concentrated at one point. This concentration of weight can become a problem

in later years when the trees are large, and they often break at this junction or

form a water pocket that accumulates water, which is undesirable.

If a primary branch grows too fast in relation to the others, it should be

checked by tipping or bending, in order to promote a balanced growth of all

the primary branches. In some species these primary branches have to be cut

back to about 60 cm, in order to induce them to form secondary branches (Fig.

4.2d), and this is followed by further pinching (Fig. 4.2e) to form a canopy

closer to the ground. A more open growth angle of the primary branches is

achieved by pulling them with strings attached to the ground or with strings

that have a weight hanging at the other end or by putting pieces of twigs

or bamboo between the branches in order to open their growth angles.

Sometimes the inner part of used tyres is put between the branches so that the

insertion angle to the stem is wider.

Formation pruning can start in the nursery or at planting time if the

plants are large or already show unwanted growth proportions, or after they

have achieved a certain size in the ﬁ eld. During the ﬁ rst years of growth in the

orchard, every 3 or 4 months the plants should be inspected and any water

sprout or sprout coming from below the graft union removed. If this is done

frequently, it can be done with the hands and no tools are needed. Longer

intervals will require pruning shears. The shoots should be cut at their base, to

prevent re-sprouting of more than one shoot.

74 Chapter 4

Production pruning

There is a growing tendency to prune adult evergreen fruit trees periodically to

manage their size. Tree size of less than 3–4 m is needed in order to facilitate

all management operations being carried out from the ground, such as

spraying and harvesting. The canopy should also not be overcrowded with

branches, which limits good light penetration and ventilation. The aim of

production pruning is to improve tree health, plant growth and ﬂ ower bud

formation and so improve fruit yields and often fruit quality (Fig. 4.3a).

At planting

(a)

(b) (c)

(d) (e)

Three primary branches

Second pinching

Six to nine secondary branches

Aerial view

<120º

Development

90–110

70–90

Cut the top

Fig. 4.2. Formation pruning, which can start in the nursery or soon after planting,

develops a central pole cut to 70–90 cm from 100 cm, retaining only three evenly

spaced lateral branches that form the basic framework of the tree and develop from

the lateral buds, ensuring that these lateral branches arise at different positions

on the pole. Additional pinching of the apical buds induces additional secondary

branches; pinching of the apical buds may be done a number of times.

Tree Management 75

Maintaining the trees at less than 3–4 m can be achieved by topping trees

either with large machine pruners or by hand, using di erent cutting devices

such as machetes, chain saws or pruning shears. This pruning becomes

a periodic or yearly operation and is often carried out immediately after

fruit harvesting in order to allow the trees plenty of time to regenerate their

productive structures. This pruning has resulted in signiﬁ cant increases in

yields and fruit quality, and in disease reduction.

Another technique used, in species like mango, is a peripheral pruning

after harvest, eliminating the outer 30–40 cm of the canopy in order to

stimulate a uniform re-growth so that all new shoots have the same age, in

order to induce uniform ﬂ owering (Fig. 4.3b). This includes eliminating all

fruit stalks left from the former harvest since they have been shown to have an

inhibitory e ect on production.

(a)

(b)

Fig. 4.3. Production pruning begins after the formation pruning and the induction

of subbranches. The most common practice is to remove branches inside the

canopy, especially those that are diseased and crossing other branches; this will also

maintain tree height. Peripheral pruning is also practised to maintain canopy size

and tree height.

76 Chapter 4

Guavas are forced to produce year round, and normally the actively

growing shoots are tipped once they become too large. This tipping forces re-

growth and new ﬂ owers to be induced, to keep production high and constant.

In guava cycling, as soon as the harvest is ﬁ nished, a peripheral pruning of

the canopy is performed, in order to force new shoots that will bear ﬂ owers.

Cherimoya and atemoya are also tipped to remove last season’s growth and

force new shoots to arise below this cut. The new shoots lead to adequate and

more uniform ﬂ owering since new ﬂ owers arise from these new shoots. If the

climate permits, this pruning can be done at shorter than yearly intervals, as

soon as the previous growth and leaves start to mature. This shortened period

can lead to fruit harvests every 7 to 9 months. In orchards where the trees in

a row are closely spaced and are starting to touch and shade each other, they

can be pruned as a hedge, by pruning the trees on both sides and leaving a

ﬂ at surface where the hedge is a bit wider at the bottom than at the top. This

is achieved by pruning at a 20° angle. The top of the hedge would also be

trimmed horizontally at this time.

In banana and plantain all but one of the suckers taller than 1 m are

eliminated, leaving one replacement sucker or son that will be the next to

ﬂ ower; the smaller suckers (grandchildren) are not cut. This practice is done

every 6–8 weeks.

Sanitary and maintenance pruning

Sanitary pruning is done to eliminate any growth that has been damaged by

diseases or by insects. It also includes branches that are broken or growing

in the wrong direction or interfering with neighbouring branches. Branches

growing towards the ground and interfering with fertilization or weeding

practices should be also eliminated. Any structure left from the former harvest

should also be eliminated. The person doing this pruning needs training in

order to make the correct decision as to what growth to eliminate. This could

include old, diseased or broken leaves in the case of papaya, plantain or

banana.

Structural regeneration pruning

This is performed to induce the regeneration of the productive structures and,

in the case of large plants, to reduce their size to facilitate ﬁ eld operations and

avoid overcrowding. In yellow passion fruit, the plants are pruned after about

3–4 years, when they start to decline, and the decision has to be made between

replanting the whole ﬁ eld or rejuvenating the old vines. If rejuvenated,

pruning is performed so as to leave the main stem and the primary branches,

which are cut back too about a metre, and all secondary branches are cut to

Tree Management 77

leave a short cane. This pruning will force new vigorous growth. Co ee plants

are cut back to 30–40 cm and they will start to regenerate their canopies, and

in this way they will be rejuvenated and return to a more manageable size and

be more productive. Regeneration pruning can also be done in old and large

trees of several species where size has reached unmanageable proportions and

there is a need to reduce it.

Pruning to change a variety

A grower can change the variety of an orchard that is mature but still healthy

and vigorous. The mature trees are pruned to leave the bases of the three or

four sca old branches (Fig. 4.4). Scions or bud-wood can be grafted on to

the stubs of the sca old branches directly or on to the shoots coming from

them. This operation reduces the time for the orchard to come back into full

production, as compared to starting with new plants from the nursery.

When large sca old branches are cut back and left without shade from

the canopy, care has to be taken to avoid sunburn. Normally the whole trunk

and the remaining portions of the sca old branches are protected with

whitewash prepared at the farm or with white latex paint. The wounds have

to be disinfected and protected; in some cases aluminum foil is used to cover

them. An alternative to this could be to cut one or two of the branches and

graft them, while the others are left intact and will provide protection and keep

the normal sap ﬂ ow within the plant; the next year the remaining part of the

plant will be cut back and grafted (Razeto, 1993).

Pruning cuts and tools

Pruning cuts, if smaller than 1 cm in diameter, are normally not treated, but

larger cuts are treated with a paste containing copper, such as copper sulfate

or other fungicide, and sometimes insecticide, to avoid the entrance of some

pathogens or insects. Under very wet situations and if certain diseases are

present, almost any cut has to be disinfected; sometimes it is best is to wait for

a dry spell to prune.

Pruning tools include pruning shears, pruning saws, chainsaws and

even machetes. Machetes are not recommended, but they are used to prune

trees that have a soft wood. Tools should be disinfected before pruning the

next tree, in order to avoid transmission of diseases from one tree to another.

In some cases, such as with ﬁ re blight, tools should be disinfected between

each cut (Harris, 1983). Disinfection is of the utmost importance with some

tree species or when disease is present, to protect the rest of the grove from

becoming infected. In banana plantations, the machetes used for eliminating

suckers are disinfected after each cut is made, to avoid the spread of ‘Moko’,

78 Chapter 4

the bacterial wilt disease. Disinfection products include an iodine-containing

odophor such as the commercial product ‘Vanodine’, sodium hypochlorite

(bleach) at a 10% diluted solution or denatured methyl alcohol (shellac

thinner). Bleach can be very corrosive on equipment, so it should be used

with care.

Fig. 4.4. To regenerate an old orchard and change the variety, growers cut back the

old tree to the main lateral branches (stag-horning) and graft the new variety scions

on to the old branches.

Tree Management 79

IRRIGATION

In some parts of the tropics with abundant rainfall, such as the Atlantic

coast of Costa Rica, which receives ~4000 mm/year, irrigation is not

necessary, even for bananas; drainage is the main concern, to remove the

excess rainwater. In tropical areas with high rainfall, most have a dry season

of a couple of months, when irrigation is needed. Installation of irrigation

will depend on an economic analysis of the situation as to whether artiﬁ cial

irrigation will improve fruit size, production and quality. The analysis should

take into consideration the species, trees’ growth phase, temperature, wind

and relative humidity during the dry months. If the dry season occurs during

the cool season, when little wind occurs or high relative humidity is present,

irrigation needs are less than if the dry season is hot and windy and the

relative humidity is low. A problem arises in abnormal years with a longer

than usual dry period, when productivity can fall signiﬁ cantly. Two or three

dry months under the tropical heat can have detrimental e ects on yields of

some species not adapted to long dry spells and it can be wise to irrigate during

the dry season.

Many fruit crops that originated in the monsoon areas need a dry period

to restrict tree growth, mature the foliage and induce ﬂ owering. The mango

is an example of a tree that evolved in a monsoon environment and ﬂ owers

better if subjected to cool weather and dry soils. In many places, mango is

grown with only rainfall, though yield may be reduced. Some fruit trees are

subjected to a water stress even when irrigation is available, with irrigation

resulting in heavier and more uniform ﬂ owering. A number of tropical species,

such as many Spondias, have evolved mechanisms to withstand the dry season

by shedding their leaves to minimize water loss.

Tropical fruit trees should be irrigated or receive adequate rainfall in order

to yield their maximum. Most modern orchards install an irrigation system

even if the rainfall is adequate to keep the plants growing; irrigation under

these circumstances will provide extra water in case of mild stress or when the

rainfall pattern changes.

Irrigation systems

The irrigation system installed will depend on many factors: amount and cost

of water, availability of money, steepness of the land, and the technical level of

the farmer. Several systems are used in tropical fruit orchards.

Surface irrigation

Surface irrigation includes furrow and basin irrigation, with furrow

irrigation being the most popular. The land needs to be fairly level or to have

been levelled during preparation (Avilan et al., 1989). Land levelling can

80 Chapter 4

be a costly operation, but once it is done, furrow and ﬂ ood irrigation will be

cheap though very ine cient in water usage. Furrows are more suited to ﬂ at

or almost ﬂ at land where the slope is 0.5–1.0%. The furrows can be made to

follow the contour, with the same slope of 0.1–1.0%. Higher slopes can lead to

erosion, which will destroy the irrigation ditches and the furrows will become

excessively deep.

In furrow irrigation, water is conducted along the tree rows and around

the trees. For young plants, one furrow is often su cient, later increased to

two furrows, one at each side of the trees, and this could be increased to four

furrows in older orchards. Furrows can also be dug around the trunk or have a

side furrow that directs water under the canopy. Furrows should be no longer

than 120–180 m in loamy soils and 60–80 m in very permeable soils. If a

furrow is excessively long, the time for the water to reach the end will allow

for excessive inﬁ ltration at the start beyond the root zone and waste water and

fertilizers. Short furrows have the opposite e ect of insu cient penetration

and faster onset of water stress.

In the basin system, around each canopy drip line a 25–30 cm mound of

soil is prepared to retain the water and allow ﬂ ooding of the canopy area till

the soil becomes saturated. This system has 35–40% water-use e ciency and

is used where water is abundant and cheap or free.

Furrow and basin irrigation are less e cient in water usage because of

the excessive inﬁ ltration at the start of the furrow and the loss of water in

transporting to the ﬁ eld. Care is taken to ensure no ﬂ ooding or excess irrigation

water comes in contact with the base of the trunk, as this can lead to serious

trunk diseases and even tree death.

Low-pressure irrigation

Drip and micro-sprinkler irrigation are low-volume, low-pressure systems (Fig.

4.5a, b). These systems can be used on steep and uneven land, and require no

land levelling. Pressure compensation built into emitters and sprinkler heads

means that all points receive similar amounts of water. Water is applied only

where needed to the plant roots, and these systems are the most e cient for

reducing water wastage. The distribution of the water in pipes and hoses

results in very little evaporative loss, saving 30–40% of the water in relation to

conventional surface systems.

Drip irrigation consists of having hoses running along the tree rows (Fig.

4.5a), and these hoses will have several drippers, normally three or four under

the canopy drip line, with one or two hoses on each side of the trees along

the rows. In sandy soils, lateral movement of water is poor, so more drippers

will have to be used or the frequency of irrigation increased. Sometimes

micro-sprinklers are a better alternative in sandy soils. Normally with micro-

sprinklers (Fig. 4.5b), there will be one per tree to keep the soil under the

canopy moist. Some large banana companies use sprinklers that hang from

cables. Watering is more frequent and a lower volume applied each time, so

Tree Management 81

that the plants do not become water-stressed, resulting in improved yields

(Baldini, 1992). The systems represent a higher initial investment, and skilled

labour is needed to install and maintain, with the beneﬁ ts of lower water usage

and greater e ciency of application. In many parts of the world, these systems

lend themselves to ‘fertigation’ or ‘ferti-irrigation’, a combination of irrigation

and fertilization. A calibrated mixer injects a ﬁ xed amount of a concentrated

liquid fertilizer stock solution into the main irrigation supply line. The amount

injected is determined by knowing the amount of water to be applied, ﬂ ow rate

and the amount of concentrated fertilizer to meet the plant’s needs.

Sprinkler irrigation

Sprinkler irrigation is still quite popular for fruit trees. Permanent and semi-

permanent or portable sprinkler systems are used. Sprinkler irrigation can

be over or under the tree canopy (Fig. 4.5b). The above-canopy system

washes pesticides o the leaves and can contribute to disease spread because

of the humidity and splashing the droplet causes. In the case of banana and

plantain, under-canopy irrigation is used. Mini-sprinklers that cover a circle

with a diameter of about 12–14 m are installed every 10–11 m in a square

arrangement. Under-canopy irrigation avoids the disadvantages of the big

sprinklers used in the past, which covered almost 1 ha. In very few situations,

(a)

(b)

(c)

Fig. 4.5. Irrigation of orchards has moved away from furrow and ﬂ ood irrigation to

the use of drip tubes (a) and micro-sprinklers (b). To determine water needs a simple

system is the use of tensiometers at different depths (c). Electrical tensiometers are

also available.

82 Chapter 4

especially with small trees like guavas that are pruned, travelling sprinkler

systems can be used successfully. Sprinkler irrigation does not require level

land, uses little labour and improves soil structure; water volumes can be

regulated; it wastes less water than surface irrigation, but it requires more

pump power, and it is more expensive to install than furrow or basin irrigation.

Sprinkler systems sometimes interfere with farm machinery operations.

Sub-irrigation

Sub-irrigation can be used in very permeable soils like the coralline soils of

Florida. Water is pumped into the drainage system and this makes the water

table rise, so that the root zone becomes saturated.

Irrigation control

An excess of water or drought a ects plant functions and thus tree yields.

Drought will reduce water availability and consequently nutrient uptake; the

stomata will close and less carbon dioxide is available for photosynthesis. With

fewer sugars produced by photosynthesis, translocation of carbohydrates

will be reduced, as well as hormonal transport from the roots to the canopy.

Excess water will create a shortage of oxygen in the soil, leading to anaerobic

conditions, which are toxic and reduce root activity and growth, often leading

to root death. Root death results in reduced water absorption and hormone

production by the roots and more pathogenic activity, which can cause root

rot and ﬁ nally tree death.

Irrigation has to meet the plant’s needs, which depend on the species, the

tree size and age, foliar density and the climatic conditions. Any irrigation

plan has to take into account the water retention of the soil, the rate of water

penetration, the distribution and depth of the root system and the amount

of water the crop uses. The amount of water to apply will depend on soil

structure and texture, and depth of the root system. Irrigation must take into

account the depth that water should reach in the soil proﬁ le, and this is based

upon root distribution and where the majority of roots are active. During tree

growth, root distribution shifts from the roots being concentrated near the

surface to becoming deeper in distribution. If irrigation is too shallow, the root

system will also remain shallow, forcing more frequent irrigation. If irrigation

is too abundant, water will pass below the main root zone and take with it

many nutrients needed for plant growth.

After heavy rain or irrigation, the soil is saturated and begins to drain

under gravity, and it reaches a point called ﬁ eld capacity (FC) about 24 h

later; that water is held by the soil against gravity. The potential (force) that

this water is held at is about 7 kPa (7 cbars, ~0.07 atmospheres) and it is

readily available for the plants. At FC, there is more water in a heavy than in

a light soil. If no further water is received by the soil, it will start to dry out,

Tree Management 83

until it reaches the so-called permanent wilting point (PWP), where most

plants are no longer able to extract water from the soil and the water potential

is too strong. At PWP, plants start to wilt, irrespective of the time of day.

Water at PWP is retained by the soil with a force of 1500 kPa (15 bars, ~15

atmospheres).

Several methods are available to determine plant needs and the amount

of irrigation that must be applied. Simple approaches involve digging a small

hole with a shovel to see if there is moisture at a certain depth or checking

whether the annual weeds in the orchard are wilting. In some cases, growers

use rain gauges (pluviometers) to determine the amount of rain and calculate

how much irrigation water to apply knowing the crop’s total water needs on

a weekly basis. Total crop water needs depend upon the surface area covered

by the crop canopy and the potential evaporation. In certain banana-growing

areas in Honduras, irrigation needs are estimated based on research data

showing that the plants need about 2000 mm of water falling on the ground,

~40 mm/week, supplied with three applications of 13 mm each time. The

amount applied is reduced by the amount of rainfall recorded in the rain

gauge in 2-day periods. For example, if it rained 6 mm they would only irrigate

to apply 7 mm.

A more accurate method is to use tensiometers (Fig. 4.5c). Tensiometers

are pieces of pipe with a porous tip where water can ﬂ ow in and out. The

pipe is ﬁ lled with water and at the other end there is a manometer, which will

measure the tension by which water is retained by the soil. The manometer is

calibrated in centibars (cbars) or hundredths of a bar, a bar being equivalent to

1 atmosphere. In a saturated soil, there will be practically no tension and the

manometer should indicate 0 cbars; at 10–25 cbars there is a good amount of

water available, while at >25 cbars, water is becoming more di cult for the

plant to extract and at 75–80 cbars irrigation is essential.

Tensiometers are usually installed at a number of locations spread

throughout the orchard and at di erent depths to represent the root-zone

conditions. If the tensiometer with the porous tip 30 cm deep shows high

tension, irrigation is necessary, while if the one with the tip at 60 cm shows

tension it means more water has to be applied to reach that depth. The 30

cm depth indicates when and the 60 cm tip indicates the amount of water

required. For avocados, irrigation should be carried out at 40–50 cbars

tension. In basin or furrows irrigation, 50–60 cbars would indicate the need

to irrigate, and with drip irrigation 10–15 cbars would be the threshold.

In the last few years more sophisticated remote indicators or sensors have

become available. Some sensors measure the electrical resistance of gypsum

or other blocks whose resistance varies according to the soil water content.

Other instruments measure the time an electromagnetic impulse takes to

travel through the soil (TDR – time domain reﬂ ectometry), and that varies

according to soil moisture content, and the neutron emitter that receives the

reﬂ ected emissions, which also vary according to soil moisture.

84 Chapter 4

A more accurate calculation of a crop’s water needs is the crop’s

consumptive water usage, which combines leaf transpiration and water

evaporated by the soil and the leaf surfaces. These losses are a ected

by temperature, relative humidity, wind speed and radiation, and their

combined value is called evapotranspiration. A type ‘A’ evaporimeter, which

is a circular tank 1.20 m in diameter and 25 cm deep ﬁ lled with water, is

used in meteorology; daily measurements are made to establish how much

evaporation occurred and it is expressed in mm/day. This value multiplied by a

location factor and the crop coe cient (Kc) (ground area covered by the crop)

will give the daily evapotranspiration or consumptive water use and is used to

calculate how much and when to irrigate according to what is evaporating.

FERTILIZATION

Fertilizer needs and dosages

A number of mineral elements are required for plant growth and development

and are classiﬁ ed, according to the amounts needed, into macronutrients and

micronutrients. Macronutrients are needed in higher amounts and include

nitrogen, phosphorus, potassium, sulfur, calcium and magnesium. The micro -

nutrients are needed by plants in lesser amounts and include iron, zinc,

boron, manganese, copper, molybdenum and cobalt. Both groups are equally

important; when plants do not have enough of any one of the macro- or

micronutrients, they are unable to complete their life cycle. In an orchard, a

shortage or deﬁ ciency is overcome by the application of fertilizer.

The amount of fertilizer to apply can be established in many ways. In

some tropical regions the nearest university or agricultural extension o ce

can provide a fairly good estimate as to the amount of fertilizer to apply for

speciﬁ c crops; published information can be a useful initial orientation as to a

speciﬁ c crop plant’s needs, and some neighbouring farmers’ fertilizer practices

can help as a starting point. A more technical approach is to determine the

amount needed to replace that ‘exported’ by the harvest. This estimate needs

to be adjusted for the amount of nutrients lost through pruning and e ciency

of nutrient uptake and the amount unavailable to the plant roots. Another

system is to establish trials using di erent dosages of fertilizers for a given

species or variety under your climatic and soil conditions. These trials can

take a long time, and often the answer is needed sooner than the results are

obtained. The other approach is to carry out soil and plant tissue chemical

analysis.

Tree Management 85

Soil analysis

Soil samples are collected before planting from a soil depth of between 10

and 30 cm with a shovel or auger. It may also be necessary to sample the

subsoil. In fairly uniform soils, soil is sampled at various points, following a

‘W’ pattern across the ﬁ eld. The soil samples are mixed for analysis. If the soils

appear to vary in a ﬁ eld, each di erent area should be sampled and analysed

separately. The analysis results will provide the soil’s pH and an estimate of the

available macronutrients and, when data are available, a recommendation

as to the fertilizer needs. For nitrogen content, the results will not be as exact.

Any deﬁ ciencies noted at this time should be corrected. It is important to

remember that the soil analysis indicates what is present but not necessarily

available for the plants; sometimes an extreme pH can block the availability

of some nutrients. So the soil’s analysis has to be complemented by the plant

analysis. The soil analysis can be repeated every 2 or 3 years to detect any

signiﬁ cant changes.

Plant analysis

Plant or foliar analysis indicates the level of a particular element present in

the plant. The amount is compared with a standard table, which have been

developed for many species after long ﬁ eld studies. This analysis makes it

possible to know if the level found in the tissue is normal, deﬁ cient or excessive.

For leaf analysis, it is important to know how the standards were developed, as

the type, number and age of leaf, what type of shoot (with or without fruit)

and at what time of the year samples were taken can change the standard

values. The samples taken will need to duplicate this sampling protocol

carefully in order to have comparative results. In banana, leaf or petiole pieces

are used instead of whole leaves. The sampling has to be performed by trained

personnel and the samples analysed by a certiﬁ ed and trusted laboratory. The

analysis results will indicate what nutrients are insu cient for the plant’s

growth or what is in excess. A decision can then be made to correct a nutrient

that is limiting growth by applying more or less of that nutrient in your

fertilizer programme (Table 4.3).

Dosages will initially follow recommendations from other growing areas

until reliable local or your own information is available. The nutrients most

commonly deﬁ cient are nitrogen, phosphorus and potassium, and sometimes

magnesium, and these are included in a regular fertilization programme.

Roughly, in the adult stage plants need around 100 kg of nitrogen, 50 kg of

phosphorus (P

) and 100 kg of potassium (K

O) per hectare per year. These

very broad referential numbers vary signiﬁ cantly with species, soil type and

plant growth stages. Banana, plantain and pineapple normally need much

more nitrogen and potassium than other tree crops. A common problem

86 Chapter 4

Table 4.3. Nutrient levels that are sufﬁ cient for growth for various selected tropical fruit crops (after Reuter and Robinson, 1986; Jones

et al., 1991).

Nutrient levels adequate for growth (%)

Tissue Nitrogen Phosphorus Potassium Calcium Magnesium Sulfur

Annona spp. Leaves 2.5–3.0 0.16–0.2 1.0–1.5 0.6–1.0 0.35–0.5

Avocado Leaves 1.6–2.0 0.08–0.25 0.75–2.0 1.0–3.0 0.25–0.8 0.2–0.6

Banana Leaves 3.5–4.5 0.2–0.4 3.5–5.0 0.8–1.5 0.25–0.8 0.25–0.8

Guava Leaves 1.3–1.6 0.14–0.16 1.3–1.6 0.9–1.5 0.25–0.4

Litchi Leaves 1.3–1.5 0.15–0.2 0.8–1.2 0.56 0.21 0.1–0.16

Mango Leaves 1.0–1.5 0.08–0.25 0.4–0.9 2.0–5.0 0.2–0.5

Papaya Petioles 1.01–2.5 0.22–0.4 3.3–5.5 1.0–3.0 0.4–1.2

Passion fruit Leaves 4.75–5.25 0.25–0.35 2.0–2.5 0.5–1.5 0.25–0.35 0.2–0.4

Pineapple Leaves 1.5–1.7 < 0.1 2.2–3.0 0.8–1.2 < 0.3

Tree Management 87

is a tendency to use an excess of nitrogen on most crops, which can lead to

excessive vegetative growth and environmental contamination, besides being

a waste of fertilizer and increasing production costs.

Timing of application

Nitrogen, if applied conventionally, should be applied three or four times a

year in equal amounts, with the ﬁ rst application before ﬂ owering or the main

growth ﬂ ush. The next applications will follow at 3- or 4-month intervals.

If there is no irrigation, the ﬁ rst application should be done as soon as the

rains start, and the other two or three divided so that the last is made 2 weeks

before the rains stop. Potassium can be split into two or three equal fractions

and applied with the second and third, and eventually the fourth, nitrogen

application, if nitrogen is applied four times a year. Magnesium can also be

split into two or three applications. Phosphorus, since it is readily immobilized

in the soil, can be applied all at once for the whole year, normally with the ﬁ rst

application of nitrogen. Nitrogen should not be applied close to harvest, as this

results in fruits that are more succulent, mature later and are not as sweet and

tasty. Nitrogen is preferably applied right after harvest

Fertilizer application

Solid application

When low-volume or sprinkler irrigation systems are not installed, con-

ventional soil fertilizer application systems are used. This application of dry

fertilizers to the soil is made by broadcasting the fertilizer on to the soil surface

over the outer half or third to the canopy drip line. There is no need to apply

fertilizer near the tree trunks, as the old roots have little nutrient-absorption

ability. Small banana growers apply dry nitrogen and potassium fertilizer

four times a year, while phosphorus is normally applied once a year; these

applications are done by applying the fertilizer in a semicircle about 60 cm

long and 30 cm wide in front of the ratoon sucker, about 30 cm from its base.

When the plants are closely spaced, fertilizer can be broadcast uniformly

in the space between rows, as it is assumed that this area is ﬁ lled with roots.

Alternatively, a shallow semicircular furrow about 40 cm long and 5 cm deep

is excavated with the edge of a hoe or square shovel 30–40 cm from the main

stem; the fertilizer is put in the furrow and covered. Sometimes fertilizers are

applied following the irrigation furrows or in the basins, which ideally should

be wet. Fertilizers such as urea should not be left exposed but covered with a

rake or irrigated into the soil to avoid volatilization of the active components.

The fertilizer should be applied when the soil is wet and moved from the

88 Chapter 4

surface into the soil by irrigation or rainfall. When irrigation facilities are not

available, the farmer should wait for a day when he is certain that there will

be rain and fertilize just before it rains. Fertilizer applied during the dry season

will not be available to the plants until it rains, unless an irrigation system

is available.

In many orchards, a wide and 10–15 cm deep furrow is made that follows

the drip line of the canopy, and the fertilizer is placed in that furrow and

buried to avoid losses. Four to six holes about 30–40 cm deep can be made in

the vicinity of the drip line in a square or a hexagon layout, and the fertilizers,

sometimes including manure, are buried.

Dilute application

Large banana companies used to fertilize every 2–3 months with nitrogen and

potassium, using ‘cannons’ or large sprinklers that covered a circle of about

a hectare. They ﬁ rst irrigated with water containing no fertilizer until the soil

was wet, then injected the soluble fertilizer into the water until the calculated

amount had been applied to the ﬁ eld and ended the process with plain water.

The last phase of irrigation without fertilizer ensured that the fertilizer had

been taken into the soil and that leaves and metallic structures in the ﬁ eld

were washed, so that fertilizer residues, especially urea, did not burn the leaves

or corrode the metals. This approach applied a large amount fertilizer a few

times a year. When sprinklers, micro-sprinklers and drippers are used, smaller

amounts of fertilizer are applied with each irrigation. The advantage of using

smaller amounts at more regular intervals is that the fertilizer is placed near

the root zone and less fertilizer is lost because of leaching. Small, regular,

almost continuous application ensures that most of the fertilizer is used by the

plants, reduces plant nutrient stress and the application rate can be readily

adjusted to the stage of plant development. Nitrogen applications near harvest

time have to be reduced or eliminated to avoid delayed fruit maturation,

excessive fruit succulence and to achieve a better-ﬂ avoured fruit. The

reduction in nutrient stress associated with almost continuous application of

fertilizer results in higher yields and allows growers to recover the investment

made in the irrigation infrastructure, in addition to signiﬁ cant reduction in

fertilizer and water usage.

Foliar fertilization

Although the roots are the main organs that the plants use to absorb needed

nutrients, foliar applications can be made to correct certain deﬁ ciencies. Foliar

fertilization is normally used to apply micronutrients and in exceptional cases

to supplement for a deﬁ ciency of a major element, especially nitrogen in the

form of urea. Because of the large plant needs for major elements and the low

concentrations tolerated by the leaves, especially urea, it is almost impossible

to ﬁ ll the needs through the leaves. Microelements are also normally taken up

by the roots, but in situations with low micronutrient availability or the root

Tree Management 89

inability to absorb them, foliar sprays provide a very rapid response, and after

2–3 weeks improvement can be noticed. Pineapple in Hawaii is sprayed at

regular intervals with an iron solution to correct a deﬁ ciency; even though the

soils are high in iron, most is unavailable to the plant.

Many fertilizer preparations contain microelements that are sprayed on

to the foliage from one to four times a year. Spray application frequency is

dependent on the micronutrient, the species and the deﬁ ciency severity. Foliar

fertilizations should not be performed at ﬂ owering time or when the fruits are

very small. Some micronutrients are applied as sulfates, such as zinc sulfate,

but since this is an acid product, it has to be mixed with lime to avoid leaf

damage. Urea, which has a high biuret content, can also cause severe burns.

Soluble forms of single essential micronutrients and mixtures of a number of

micronutrients, as their sulfates, nitrates and chlorides and complexed with

chelating compounds (EDTA), are available commercially. These products can

be tried and used if satisfactory results are obtained.

For best results, foliar fertilization by spraying young leaves will make it

easier for the product to be absorbed, since the leaf cuticle is thinner. If the

spray drop size is small, repeat applications at lower concentrations enhance

uptake. Since a liquid is applied to the foliage, the more foliage it covers and

the longer it stays as a liquid the more nutrients will be absorbed by the plant.

Application during cooler, high-moisture and calm air conditions is the best

to obtain maximum beneﬁ ts, with early-morning sprays being recommended.

Covering both sides of the leaves, especially the underside, with the greater

number of hairs and pores and less wax, aids in foliar nutrient uptake. The

addition of a spreader sticker to the foliage fertilizer mix can also increase

uptake. Some foliage spraying can be done in combination with disease

and insecticide sprays after checking for compatibility. Phosphates are not

compatible with salts of copper, manganese, zinc and iron; copper fungicides

should not be mixed with sulfates, nitrates or chlorides. If a new product or

procedure is being used, test the mixture on some plants before spraying the

whole ﬁ eld.

CROP PROTECTION

Fruit crops can be a ected by insects, mites and nematodes, and diseases

caused by bacteria, fungi, viruses and similar organisms. Vertebrate enemies

such as rats, squirrels, monkeys, birds and bats can also be a problem. Since

fruits are expected to be without blemishes, and more so if they are for export,

the tolerance is zero for damage. It is not possible to obtain blemish-free-

quality fruit without using pesticides. For many tropical fruit crops, there

are few approved pesticides, and the residues tolerance is low, and varies

with market.

90 Chapter 4

Insects

Insect pests are a major problem in agriculture, including tropical fruit

production. Most insects are harmful because they chew plant parts or

suck their ﬂ uids. Some insects are borers that damage the branches or

stems. Additionally, some sucking insects can transmit viruses, viroids and

mycoplasmas that cause diseases if they come from an infected plant. There

are also beneﬁ cial insects such as honey bees, silk worms, those involved in

pollination, predators that eat harmful insects and parasites that lay their eggs

into the insect pest; the parasite eggs hatch and the larvae consumes the pest

larvae or pupae.

Insect control using integrated pest management (IPM) requires

knowledge of the insect life cycle and habits. Questions asked include: Where

do they lay their eggs? How much time does it take to become larvae? How long

are the larvae active before becoming pupae? Where do they stay during these

stages? What are their feeding habits? What species and what part of the plant

do they attack? What are their migratory habits? Knowing this information

allows the IPM person to design a strategy for controlling them.

A major pest such as fruit ﬂ ies requires a preventative approach for its

control, since once the ﬂ ies lay their eggs, the fruits are di cult to market

unless subject to a kill or sterilization treatment. Frequent preharvest sprays

and traps can be used for fruit ﬂ y control, though costly. Fortunately, fruit ﬂ ies

do not generally lay their eggs into unripe fruit, therefore harvesting at early-

ripening stages avoids major fruit ﬂ y injury. Fruit ﬂ ies are a signiﬁ cant insect

problem in fruit export, since the USA, Japan and others have very stringent

quarantine regulations and in many cases require the fruit to be treated

before entry.

Insect traps in the ﬁ eld (Fig. 4.6a) give an indication about the insect

species present and their population size, and this is used to decide if spraying

is necessary. Some traps used have light as an attractant and have either a

pan ﬁ lled with soapy water to reduce surface tension so that the insect sinks

into the water, or kerosene or water with a contact insecticide is used to kill

them. Other traps use a lure, which can be a pheromone or a particular

scent that will make the insect go to the trap and be killed in similar ways.

Another way is the use of attractive plastic sheets with a sticky substance in

the nursery (Fig. 4.6b) and in the ﬁ eld (Fig. 4.6c), which will immobilize and

thus kill the insect.

Among the exclusion methods used are barriers and tall plant fences,

which will not keep insects out but will reduce the number of insects visiting

the ﬁ eld. Anti-insect fabrics exclude insects completely but they are expensive,

although they are used to exclude aphids from papaya trees in some areas (see

Fig. 3.9b). Another exclusion method is bagging the fruit (Fig. 4.6d), which is

very e ective in preventing fruit ﬂ y and other insects from laying eggs.

Tree Management 91

Cultural practices can be used, such as ploughing or discing to kill insects

present in the soil, weed control to remove shelter and an alternative place

to reproduce, and pruning damaged parts and burning them. In the case of

fruit ﬂ ies, all fallen fruit should be buried at least 40–50 cm deep so that if

the larvae evolve into pupae there will be no chance for the ﬂ ies to reach the

surface. High-pressure water sprays can also be used for control, and in other

cases, hand collection of the leaves with larvae that have hatched from eggs or

of larvae shaken from the plants.

Biological control includes the use of predators’ parasites as well as

bacterial and fungal enemies. In many cases insect damage can be solved

by releasing predators or parasites that can be acquired commercially and

released in the orchard. This approach provides a very e ective long-term

biological control. Examples include the e ective control of many scales and

aphid insects in di erent parts of the world. The bacterium Bacillus thuringensis

is used widely to control many leaf-eating larvae and the fungus Beauveria to

control a number of pests such as whiteﬂ y and di erent beetles.

(a)

(c)

(b)

(d)

Fig. 4.6. To protect the trees and fruit, various approaches can be used to reduce

the insect pest levels by use of traps (a), which may include a lure or sticky traps

in the nursery (b) and in the orchard on the trunk (c), and protecting the fruit by

bagging (d).

92 Chapter 4

Chemical control is obtained by using insecticides. Insecticides act by

poisoning the insects that ingest the sprayed plant. The ingestion of the

insecticide can occur by direct contact, inhalation of the toxic vapours or

when systemic products are used that get into the plant sap through either the

leaves or the roots, and as the insect sucks this poisoned sap, it is killed. There

are also repellent substances that keep the insects from attacking the plants;

in some cases they are plants. For chewing insects, products that act through

ingestion or contact are used. For insects in older stems, trunks, roots and

seeds, control is obtained either by fumigation or with a contact insecticide.

For insects sucking aerial or root parts, a contact and a systemic insecticide

can be used.

Most newer insecticides are less harmful to the environment, the farmers

and the consumers. The new products are very speciﬁ c and short-lived in the

ﬁ eld, so that their poisoning e ect is not as long-lasting as it used to be with

the old insecticide compounds. The grower should always make sure what

the best product is for controlling an insect and if it has been approved by the

government or the importer for that species, especially in case of an export

product. For ﬁ eld safety, the requirements as to how soon after spraying

people can re-enter a ﬁ eld and what is the minimum time before harvest that

the insecticide can be applied should be determined. Some friendlier products

include pure soap, oils and plant extracts, which can be very e ective for

some insects.

Mites

Mites belong to a di erent group and are related to spiders. They normally

rasp the underside of the leaves and feed on the sap, damaging the plant and

its ability to photosynthesize. Mites can become more of a problem when

the plants have a shortage of water or fertilizer. Normally they are on the

underside of the leaves, making it more di cult for sprays to reach them.

Their control should start with feeding and watering the plants. Biological

control measures include the use of predatory mites. The chemical approach

includes the use of some fungicides such as sulfur and some dithiocarbamate

fungicides. Speciﬁ c acaricides are based on pyrethroids, and in recent years

many new compounds have been developed, most of them interfering with

mitochondrial activity. For best control, it is often necessary to apply another

product 5 days later to kill the new adults that emerge from the eggs. Rotating

products avoids the build-up of resistance. During spraying it is essential to

cover the underside of the leaf where mites are found.

Tree Management 93

Diseases

Diseases are caused by bacteria, fungi, viruses and other organisms, such as

mycoplasmas and viroids.

Bacteria

These organisms are the cause of moist foul-smelling wounds, necrosis, galls

and wilting, because they can infect the vascular system and clog it. Bacteria

can be controlled with antibiotics such as streptomycin, but these products

are fairly expensive. The measures to reduce their appearance and progress

are to select propagating material that is clean and avoid excess moisture.

Disinfecting any tool before using it on another plant and destroying any

diseased material by burning are other simple techniques.

Fungi

Fungi are the most common cause of plant diseases. For a fungal attack to be

successful it will depend on the status of the plant; the presence of mechanical

breaks in the cuticle, the plant’s susceptibility to the fungal strain, the plant’s

stage of development; the fungal development stage and the environmental

conditions. Relative humidity of 90–100% is optimal for fungal development,

with dew sometimes creating favourable conditions.

All fungi need a certain combination of temperature and relative

humidity to become a problem; hence many fungal diseases can be a serious

problem in some situations and seasons but not in other conditions. Fungal

diseases can be avoided through resistance in a few cases. Well-fertilized

plantings with a good drainage system and careful irrigation to avoid excess of

water will reduce the risk of root diseases. Disinfection of pruning and other

wounds, control of host weeds and spraying with speciﬁ c fungicides all help

in controlling diseases. Preventive applications of fungicides are often used

with some crops, such as papaya against anthracnose, where all stages of fruit

development are present versus application only at certain stages, such as

during mango ﬂ owering.

Fungicides act via contact or systemically, with many products being

available in the market. In most cases, fungicides have to be rotated to avoid

resistance development; this is especially acute for postharvest use. It is

important to check the toxicity of the product and the waiting time before

harvest. Fungicides in general are less toxic than insecticides, and in the last

years several new products have been developed that are more e ective and

also friendlier to the environment. Several older products are still available

that are cheap and e ective. Examples include copper sulfate, copper oxide,

Bordeaux mixture (a copper derivate), sulfur and some oils.

94 Chapter 4

Virus and viroids

Viruses are very simple microscopic agents that possess either RNA or

DNA that is encapsulated in a protein coat. They are capable of replicating

themselves inside the plant using the plant cell’s own metabolism. Viroids

di er from viruses in being composed of only a single strand of ribonucleic

acid but are not protected by a protein coat. Virus diseases are normally

transmitted by contaminated propagation material, such as seeds, cuttings,

layers, budwood or entire plants, hands or tools that are contaminated or by

insect transmission. Insect transmission is probably the most important way

viral diseases are spread, and aphids are one of the most important vectors, as

well as some other insects such as thrips.

Once a plant is infected with a virus, it is not possible to cure that plant.

Sanitation is by removal of the diseased plants and using plants that serve as

host vectors for the virus and insect. Careful disinfection of hands and tools

such as grafting knives, pruning shears or saws is a must. Seed disinfection

can also be e ective with some plants of the Solanaceae family. If an economic

analysis can justify its use, an anti-aphid screen or fabric can be used, as is

done in some papaya ﬁ elds.

Viruses can kill a plant or reduce production and quality of fruit. Some

cause di erent types of leaf spots such as mosaics, while others can cause

leaf yellowing, stunting and curled leaves. Some species will show no obvious

visible symptoms but are still infected. Clean material can be obtained by

meristem culture combined with thermotherapy, micro-grafting, ovule and

nucellar embryo culture. Some viral diseases are not seed-transmitted and

the seeds act as ﬁ lters. Care has to be taken with the plant material taken to

the farm and to keep it as clean as possible. At country level, strict quarantine

is important to avoid the importation of new viruses carried unknowingly

by people.

Nematodes

Nematodes are non-vertebrate animals that can be plant parasites. Most of

them attack the roots, causing galls, wounds, tumours and lesions. Their

feeding reduces plant vigour and yields. Several genera of nematodes –

Meloidogyne (knot nematode), Ditylenchus, Tylenchus and Radopholus – cause

plant diseases, and the last two are parasites of citrus roots.

Nematodes are more common in sandy soils and their control, till

now, has been by the use of fumigants. Fumigants are very poisonous and

the results obtained from their use have been mixed. Once you start on a

fumigation programme you have to continue. Post-plant nematicides are also

available. Other approaches are rotations that involve trap crops, organic

matter addition and soil solarization, which can be used with short-cycle crops

such as pineapple and banana.

Tree Management 95

Vertebrate enemies

Birds, bats, squirrels, rats, monkeys, pigs and other animals, including

elephants, can become a real problem in orchards. These animals cause

damage to the tree trunk and eat the fruit. Birds can devastate a whole crop,

with several methods having been tried and discussed in Chapter 3.

For rodents, metallic plates around the trunks can be used to prevent them

from climbing to the tops or to prevent damage to the bark of the base of the

tree. Poisoned baits or para n blocks containing an attractant and a poison

that are fairly weatherproof are also a good solution. The use of repellents or

trunk protectors can sometimes be useful.

Other less important miscellaneous problems include algae, mosses and

parasite plants. Algae can be controlled with copper.

Integrated pest management (IPM)

This approach involves the use of many of the above procedures and

practices in combination to obtain the best control with the least

environmental impact. A careful analysis of the crop and pests’ development

cycles need to be established to develop a strategy to combat the problem

at its most susceptible phase. Computer systems can assist by analysing

the environmental conditions and predicting the development of certain

problems. IPM potentially can save money, protect the environment and

allow the orchardist to market a product with fewer pesticide residues. For

tropical fruit the market demands products that are of the highest quality,

and without blemishes or insect and disease damage, making it di cult to

avoid the use of some chemicals (Penman et al., 2003).

GIRDLING AND SCORING

Girdling consists of taking o a ring of bark, 4 mm to 3 cm wide, from the

main trunk (Fig. 4.7a), sca old branches or smaller branches to stop the

movement of sugars in the phloem, especially from the canopy to the roots.

This procedure is usually done with two knives or blades that are joined or

welded together to cut through the bark and phloem, which are removed once

the cuts have gone around the whole stem. Sometimes spiral girdling is used,

and semi-girdles of two Cs in opposite positions but at di erent heights of the

branch are used to avoid a complete blocking of the ﬂ ow.

Scoring is a mini-girdle by which the bark of the trunk or branch is cut in

a circumscribing form with a saw blade or a knife. This wound is very narrow

and will take about 3 weeks to heal, while a normal girdle will take about

3–4 months. Scoring is made by orchardists to manage fruit tree size and to

improve yield. However, scoring has variable e ects on vegetative growth,

96 Chapter 4

possibly due to imprecision that is inherent in cutting a tree with a saw or

knife blade.

Girdling and scoring are used in some fruit trees for di erent purposes.

In the case of layers or air layers (marcotts or gootees), a 3 cm-wide ring of

bark is removed at the point just below the zone where new roots are expected

to arise; the interruption of the phloem ﬂ ow stimulates adventitious root

formation above the girdle. Sometimes the branch from which grafting or

budding material is to be obtained is girdled below these buds 2 or 3 weeks

before material is to be removed. The objective is to induce bud swelling, which

results in higher grafting and budding success rates.

Another objective of girdling is to stimulate ﬂ owering. In very hot areas

with no cool or dry period to induce mango ﬂ owering, a 3-cm girdle is done on

a primary branch to induce ﬂ owering. The problem is that 5% of the branches

often die. The girdling technique is also used on avocados, macadamias and

litchis, in order to improve ﬂ owering, fruit set or fruit size. For better fruit

set, girdling or scoring should be done at petal fall, while for larger fruit size

(a)

(d) (e)

(b) (c)

Fig. 4.7. Girdling is used to aid in inducing ﬂ owering (a). To protect young trees

that are susceptible to full sunlight, simple structures such as palm fronds are used

(b), to plastic shade structures (c) and wrapping pineapple fruit with paper to reduce

sunburn (d). Some crops may need to be protected from rainfall (e) during ﬂ owering

and fruit development, with rain shelters built over the crop in the ﬁ eld.

Tree Management 97

girdling is done at the end of the initial small fruit drop. Girdling has been used

to improve avocado fruit size, especially ‘Hass’ (McNeil, 2001). A longer-term

objective is the elimination or modiﬁ cation of biennial bearing in some tropical

and subtropical fruit trees. Litchi girdling is done before ﬂ ush initiation,

around September in the northern hemisphere, to induce more ﬂ owering

and increase fruit yield. Only one of the three or four main branches should

be girdled, in order to avoid the danger of killing the tree. Girdling should be

preceded by a heavy irrigation and fertilization for better results. Normally if

there was a poor crop the previous year, girdling will work, while if there was

a heavy crop, no girdling should be done. It is recommended that girdling or

scoring be done for no more than 3 years in a row. Girdling is not a standard

practice and, in many cases, growers will use it when they have marginal

yields and will forget about this practice when good yields are being obtained.

DEFOLIATION

Most tropical fruit trees are evergreen and usually do not shed their leaves.

An exception is some Spondias species that lose their leaves during the dry

season as a drought-protection mechanism. The trees begin ﬂ owering while

completely bare. Some other trees, such as avocados in the subtropics, might

have a heavy loss of leaves just before ﬂ owering time. Artiﬁ cial defoliation is

practised in di cult-to-graft trees, where the portion of the branch from which

bud-wood is going to be taken is defoliated 2 or 3 weeks prior to collecting the

scions. This defoliation stimulates the lateral buds to start swelling and become

more active, and ensures better budding or grafting success.

Cherimoya and atemoya, being more subtropical, are sometimes classiﬁ ed

as semi-deciduous. The lateral buds of these species are covered by the leaf

petioles (see Fig. 6.1) and are not at the leaf axils, as in most plants. Thus the

leaves have to fall or be removed for the bud to burst. Defoliation is done to

induce uniform sprouting of these buds just before the new growth is about to

start and natural defoliation has not been complete. This is achieved by hand-

stripping or with the application of urea or other defoliants, at the time of

pruning, to induce a new cycle of ﬂ owering and fruiting.

PLANT GROWTH REGULATORS AND OTHER STIMULANTS

Plant regulators have been studied for many years and some practical uses

have been developed. Among the most common uses of plant regulators is the

improvement of rooting of cuttings or air layers with auxin-like compounds

such as indole butyric acid (IBA) or naphthalene acetic acid (NAA). These

auxins improve rooting percentage, accelerate adventitious root emergence

and increase the number of roots a layer or cutting will form.

98 Chapter 4

Some trials have been made to enhance fruit set in cherimoyas and

atemoyas. Auxins will reduce fruit drop while gibberellins will improve fruit

set and growth rates. In some trials seedless fruits of atemoya have been

obtained, but repeated sprays have to be done during the ﬁ rst 2 months and

fruit size is smaller and ﬂ avour is poorer. Similar results have been obtained

with cherimoya and sweetsop. None of these practices are commercially used.

In guava, trials have been done to reduce the number of seeds with auxins

and gibberellic acid; the latter has reduced the number of seeds and enhanced

soluble solids but is not used commercially.

In commercial pineapple production, ﬂ ower induction is carried out to

obtain more uniform ﬂ owering. The plants are sprayed, once they achieve the

right size, with ethylene gas dissolved in water or ethephon (2-chloro-ethyl

phosphonic acid), an ethylene-releasing compound. Also, acetylene generated

from calcium carbide reacting with water can induce ﬂ owering; this product

can be applied dissolved in water as a spray or by putting a little amount of

it in the cup formed by the leaves in the centre of the plant. Since ethylene is

the ripening hormone that plants and fruits produce naturally, many fruits

are treated with ethylene gas or ethephon to hasten and to obtain uniform

ripening. This is done commercially with bananas. For citrus, it helps achieve

better rind colour.

Some growth retardants, such as pachlobutrazol and uniconazole,

which act as gibberellin antagonists, are used commercially to prevent

mango shoots from re-sprouting too soon. This treatment allows the shoot

to achieve a minimum age, so that when it does sprout it is a ﬂ ower panicle

instead of a vegetative shoot. These products have not been approved by the

US government but are used outside of the USA.

Potassium nitrate or ammonium nitrate is used to induce ﬂ owering in

mango. This foliar application treatment is more successful if the shoots have

achieved certain age and are mature. This treatment is more successful in the

tropics than the subtropics. In the case of longan, potassium chlorate can be

applied to the soil to induce ﬂ owering. Dinitro-orto-cresol (DNOC) has been

used to burn mango inﬂ orescences in order to force a second ﬂ owering a few

weeks later, when climate or market conditions are more suited.

POLLINATION

Some fruit species have self-sterility problems and will not produce good yields

in single-variety planting. The species can be completely or partially self-sterile

or the plants can have di erent sexes or because of dichogamy, when there is

no coincidence of the maturation time of the female and male organs of the

ﬂ owers. Often more than one genotype has to be present in the ﬁ eld or artiﬁ cial

pollination has to be done. In other cases, a certain number of male plants

have to be inter-planted among female plants. For avocados that have A and

Tree Management 99

B ﬂ owering habits, there has to be a combination of both types in the orchard

to get proper pollination, fruit set and yields. Macadamia or carambola require

two or three varieties in the orchard to achieve higher yields, since most

varieties are partially self-incompatible and intercrossing results in higher

yields. In carambola, sometimes a branch of the rootstock is left on the tree

to ensure better fruit set. Date palms are dioecious and wind pollinated, and

one male plant is planted for every 10–14 female plants, distributed uniformly

throughout the orchard. Male date inﬂ orescences can be shaken in front of

female inﬂ orescences to achieve better fruit set, and sometimes pure pollen is

obtained and applied to the female ﬂ owers with dust blowers.

The dichogamy in cherimoya, atemoya, soursop and other Annonas makes

it necessary to hand-pollinate either by collecting pollen of ﬂ owers that opened

the day before in glass jars or by collecting pollen from ﬂ owers in the ﬁ eld in

the male stage to apply it to ﬂ owers in the female stage. This can be done with

a No. 4 ﬁ ne paint brush made with camel hair or with a hand mist blower (see

Fig. 6.4) using pollen dissolved in Lycopodium spores to be able to pollinate

more ﬂ owers. In soursop, which has moist pollen and large ﬂ owers, this can be

done with the ﬁ ngers.

Yellow passion fruit is self-sterile and carpenter bees (Xylocopa) have

to be present to get proper fruit set. When bees are absent, hand-pollination

has to be carried out using cloth gloves to collect the pollen from ﬂ owers in

the contiguous plant row to ensure that it comes from a di erent genotype,

since plants come from seed. This is done in the afternoon since ﬂ owers open

at noon.

The presence of bees, carpenter bees or common ﬂ ies is a great help in

achieving better yields. For bee pollinatation, four to six bee hives per hectare

should be in the ﬁ eld at ﬂ owering. In some places, mango trees in ﬂ ower are

sprayed with a solution of manure to attract as many domestic ﬂ ies as possible

to the orchard to improve pollination.

TEMPORARY SHADE, SHELTER AND BAGGING

Some tropical fruit species that originated in forests may beneﬁ t from being

under partial shade during their ﬁ rst years in the ﬁ eld. This is the case for

mangosteen, durian, jackfruit, acahachairu and other species. Semi-shade is

provided by planting certain bushy plants, such as pigeon peas, castor beans,

bananas or small fast-growing trees, around the planting hole or making a

tent-like structure with palm leaves (Fig. 4.7b), branches with leaves or shade

cloth (Fig. 4.7c). This shade will avoid sunburn damage and provide the plants

with less-stressful growing conditions. Some fruits, such as pineapple, are also

susceptible to sunburn and are protected by tying the leaves together over the

100 Chapter 4

fruit, placing straw around the fruit and the use of plastic or paper wrappings

(Fig. 4.7d).

Rain shelters are sometimes constructed to protect a fruit crop from

incessant light rain showers (Fig 4.7e). This can be seen when grapes are

grown in the tropics and mango in Okinawa, to protect the fruit from disease

and for pollination, respectively.

To harvest high-quality, blemish-free fruit, bagging when the fruits

are young is often practised (Fig. 4.7d). Often the fruits are sprayed with a

fungicide, thinned and the remaining selected fruits bagged. The thinning

allows a grower to ensure that each remaining fruit has su cient leaves on

the stem for fruit growth and development. Though there is a cost associated

with this bagging operation, the harvested fruits are blemish free, without

disease and insect damage, and more than 90% are marketable. For fruits

that are not bagged, 50–70% of the harvested fruit maybe marketable and a

smaller percentage will be of the highest grade. Another advantage of bagging

is that it evens out labour needs by moving some of labour requirements from

harvesting to thinning and bagging and thereby o ers more continuous work

for good workers whom you wish to retain.

FURTHER READING

Chandler, W.H. (1958) Evergreen Orchards. Lea and Febiger, Philadelphia, Pennsyl-

vania.

Coronel, R.E. (1983) Promising Fruits of the Philippines. College of Agriculture, University

of the Philippines at Los Baños, Laguna, Philippines.

Morton, J.F. (1987) Fruits of Warm Climates. J. Morton, Miami, Florida.

Popenoe, W. (1974) Manual of Tropical and Subtropical Fruits. Facsimile of the original

1920 edition, Hafner Press, New York.

Samson, J.A. (1986) Tropical Fruits, 2nd edition. Longman, New York.

(R.E. Paull and O. Duarte)

POSTHARVEST TECHNOLOGY

INTRODUCTION

Postharvest handling refers to all the steps that take place at harvest and

from harvest through to when the consumer receives the fruit (Fig. 5.1). The

goal of postharvest handling is to maintain quality. Quality is deﬁ ned as the

absence of defects or degree of excellence and includes appearance, colour,

shape, injuries, ﬂ avour, taste, aroma, nutritional value and being safe for the

consumer (Abbott, 1999; Shewfelt, 1999). Fruit qualities when consumed are

decided in large measure before harvest and depend upon variety grown, crop

management (fertilization, irrigation, etc.), environment (climate, soil) and

other preharvest factors. The objective of postharvest handling is to maintain

quality by preventing mechanical injury, water loss and disease development,

limiting unwanted physiological changes and preventing chemical and

microbial contamination (Cook, 1999).

Farmers, packers, shippers, wholesalers, retailers and consumers fre-

quently have di erent perspectives with regard to quality and often place

di erent emphasis on the di erent components of quality. In research, quality

is related to some intrinsic character(s) (appearance, colour, acids, sugars, etc.)

and how these characters change during handling. The research data give us

information as to how a product should be handled postharvest. The data need

to be complemented with simulated shipping studies and the evaluation of the

product from initial commercial shipments.

POSTHARVEST LOSSES

During postharvest handling, losses frequently occur, referred to as shrink in

the commercial and retail trade. These losses mean a complete loss of all the

resources that went into production. Estimates of tropical fruit postharvest

losses in both developed and developing countries vary widely from 10 to

80%. The losses given in published reports highlight the total postharvest

102 Chapter 5

losses of products but do not consider the loss of quality or nutritional value

and the downgrading that may reduce the price received. Losses may be due

to mechanical injury, physiological damage or pathogens. Once a tree comes

into production, the most expensive cost is the cost of labour to harvest and

to prepare the fruit for market; that in developed countries ranges from ~30

to 80% of the total operating costs for the year. The reduction of losses in a

systematic way requires a knowledge of postharvest physiology, its applied

technical aspect, handling and the appreciation of its biological limitation,

represented as storage potential (Paull et al., 1997).

Harvested by hand – maturity

– grade

Placed into shoulder bag

Poured into field bin or lug box

Transported to packing house

Water- or hand-unloaded

Culling

Disinfestation treatment

Sprayed with wax and fungicide

Culling

Weight/colour sorting

Hand packed into cartons

Cooled to 10–12

Loaded into shipping container

Air or sea transport to market

Fig. 5.1. Generalized fruit-handling scheme for tropical fruit.

Postharvest Technology 103

GENERAL CHARACTERISTICS OF TROPICAL FRUIT

Like all fresh fruit and vegetables, tropical fruits have four general

characteristics that need to be understood and considered during postharvest

handling. These characteristics are the reason why postharvest technology is

needed. The characteristics are:

1. All fresh fruits after harvest are still living and respiring.

2. All fresh fruits have a high water content (~90%), and after harvest it is no

longer being replaced from the plant yet they continue to lose water.

3. All fresh fruits are subject to pathogen attack before and after harvest.

4. All fresh fruits are made up of diverse morphological structures, with the

edible tissues varying between di erent fruits, and hence they have di erent

composition and physiology.

The edible fruit tissues in tropical fruits are derived from many tissues, such as

the ﬂ oral receptacle in strawberry and cashew, the fused clustered ﬂ owers in

pineapple, the entire pericarp in tomato, the exocarp and mesocarp in apple

and peach, the mesocarp only in papaya, the endocarp in citrus, the aril tissue

arising from the funicle in litchi and durian, and the seed coat in rambutan

(Fig. 1.1). This diversity needs to be understood as it inﬂ uences how a fruit will

respond to postharvest handling treatments.

The objective of postharvest handling is to minimize adverse changes in

these characteristics, especially respiration, dehydration and pathogen attack.

Losses postharvest are tied directly to these adverse changes, often associated

with poor storage environment and mechanical injury. Mechanical injury,

besides causing unsightly scarring, also increases water loss and susceptibility

to pathogens. The component of the storage environment over which we have

the greatest control postharvest is temperature. Proper storage temperature

and avoiding mechanical injury are the two most important variables in

postharvest handling.

POSTHARVEST PHYSIOLOGY

Tropical fruit physiology does not di er from the basic knowledge gained from

studies of temperate and subtropical fruits. Di erences occur between fruits in

the major substrates involved in ripening, the rate of ripening and senescence,

and in some cases variation in the order in which various components of

ripening occur. The aspects of tropical fruit physiology that make these fruits

unique are:

• their chilling sensitivity;

• the generally more rapid ripening of climacteric tropical fruits when

compared to temperate fruits; and

104 Chapter 5

• the frequent need in postharvest handling to expose them to high

temperatures or other stresses during insect disinfestation prior to export.

Respiration is the conversion of sugars such as glucose into carbon dioxide,

water, chemical energy and heat. The chemical energy (ATP, NADH) is used

to synthesize the molecules needed to keep the cells alive and to grow. The heat

represents the inability of the cell to capture fully all the potential energy in

the sugar. The simple overall equation for glucose respiration highlights the

relationship between storage environment and respiration, which is directly

FURTHER READING

Arpaia, M.L. (1993) Preharvest factors inﬂ uence the postharvest fruit quality of tropical

and subtropical fruit. HortScience 29, 982–985.

Kader, A.A. (2002) Postharvest Technology of Horticultural Crops, 3rd edition. University

of California Agriculture & Natural Resources, Oakland, California.

Kays, S.J. and Paull R.E. (2004) Postharvest Biology. Exon Press, Athens, Georgia.

Wills, R., McGlasson, B., Graham, D. and Joyce, D. (2007) Postharvest: an Introduction to

the Physiology and Handling of Fruit, Vegetables and Ornamentals. CABI Publishing,

Wallingford, UK.

(R.E. Paull and O. Duarte)

ANNONAS: CHERIMOYA, ATEMOYA

AND SWEETSOP

Three Annona species will be covered in this chapter. One species is thought

to have originated in Central America (sweetsop or sugar apple, Annona

squamosa), while cherimoya (Annona cherimola) origins are the highland

plateaus of the Andes. The third is not a species but a cross between sweetsop

and cherimoya and called atemoya (A. squamosa × A. cherimola), the ‘ate’

from the Brazilian word for sweetsop and ‘moya’ from cherimoya. All three

are found cultivated or naturalized throughout the tropics. Cherimoya is

better adapted to cooler, drier and subtropical climates, and sweetsop in moist,

tropical climates and in drier, subtropical climates.

BOTANY

Family

Annonaceae, in the Order Magnoliales, commonly referred to as the custard

apple family, consists of about 75 genera, widely distributed. The family is in

the basal group of the dicots. Some are grown as ornamentals, while only four

genera produce edible fruit. This chapter will focus on the three Annona species

widely grown for fruit.

Important genera and species

The genus Annona is the most important, being the second largest genera in

the family, and among its 100 or more species, seven species and one hybrid

are grown commercially. All are native to the American tropics. Leaves are

alternate, simple and entire, and ﬂ owers may be solitary or in clusters, with

two series of three thick and ﬂ eshy petals. The other closely related genus with

some commercial fruit is Rollinia.

124 Chapter 6

The important commercial species are:

A. cherimola Mill. Cherimoya (English); chirimoya (Spanish);

cherimolier (French); anona (Mexican); noina

ostrelia (Thai); chirimoya (German)

A. squamosa L. Sugar apple, sweetsop (English); anon, riñón

(Spanish); noina (Thai); nona seri kaya (Malay);

custard apple (Indian)

A. squamosa × A. cherimola Atemoya, custard apple (English); atemoya

(Spanish)

Annona diversifolia Sa . Ilama (English, Spanish)

Annona glabra L. Pond apple (English); mamon (Philippine)

Annona montana Magfady Mountain soursop (English); guanábana

cimarrona (Spanish)

Annona muricata L. Soursop (English); guanabana, atio

(Philippines); guanábana, catoche (Spanish);

durian belanda, nona sri kaya (Malay); nangka

belanda (Indonesian); thurian-khaak (Thai);

sitaphal (Indian); fruta de conde, graviola

(Brazilian); zapote agrio, catoche (Mexican);

corossol épineux (French)

Annona reticulata L. Custard apple, bullock’s heart (English); anon,

anona, corazón (Spanish)

Rollinia orthopetala R.DC. Biriba (Brazilian).

Area of origin and distribution

Cherimoya (A. cherimola Mill) is thought to have originated in the highlands of

Ecuador and Peru. The antiquity of the fruit is attested to by ancient artifacts

shaped in the form of the fruit in Peru. Distribution through Central America

and Mexico probably occurred at an early date, as it has become naturalized in

the cool highland areas. Distribution continued from Mexico to the Caribbean

islands and then to the African coast and the Mediterranean. Introduction to

Africa and the Far East is attributed to early Spanish navigators.

The cherimoya is considered the best of the Annonas and is cultivated in

subtropical regions and in the tropical highlands. In most areas, it is grown

as a garden tree or as part of a subsistence farming system. Commercial

production occurs in Spain, Bolivia, Chile, Peru and New Zealand (George

and Paull, 2008). Experience has shown that the California coastal regions

are more conducive to cherimoya production, having higher relative humidity

(RH) (70–80%) in spring and summer than in the interior valleys, where the

RH can drop to less than 40% during the hotter part of the day in summer.

The tree grows to about 7.3 m; it is vigorous when young but tends to

decline in growth with age. New buds cannot sprout until the leaves have

been shed, as the leaf bases grow over the axillary buds, as in sweetsop and

Annonas: Cherimoya, Atemoya and Sweetsop 125

atemoya (Fig. 6.1). Leaves are 10–25.4 cm long, light green and arranged

alternately. Leaves tend to fall before spring, and many people call it a semi-

deciduous plant.

The sweetsop (A. squamosa L.), also called sugar apple, probably originated

in the Caribbean region and is the most widely distributed and also the most

commonly grown Annona species in the tropical regions of the Americas,

Africa, Asia and the Paciﬁ c. It is less tolerant of cold temperatures than

the cherimoya but more tolerant than the soursop, as it is found thriving

in subtropical areas, such as the coastal areas of south Florida. The fruit

is frequently found in village markets but has not shown any potential for

large commercial cultivation, due to the small fruit size, frequent cracking at

maturity and poor shelf-life. It is intensively cultivated in Taiwan, where about

5000 ha are planted, producing around 50,000 tonnes; the peak harvest is

between July and March

The tree is normally smaller than the cherimoya, attaining heights of

3.0–4.6 m, with slender branches. The leaves are oblong–lanceolate, narrower

than those of the cherimoya and 10–15 cm long (Fig. 6.1). All leaves are shed

before new shoots appear. Flowers are axillary, in clusters of two to four on

leafy shoots (Fig. 6.1). Fruit set is better than in the cherimoya.

The fruit is more nearly heart-shaped, 5–10 cm in diameter. It is yellowish-

green in colour, but a purple-fruited variant is also known. The exterior parts

of adjacent carpels are not completely fused, and these rounded protuberances

3 mm

Fig. 6.1. Leaves, axillary buds and ﬂ ower of sweetsop. The ﬁ gure shows the buried

nature of axillary buds, which can be vegetative or a mixed ﬂ ower and vegetative

bud. The leaf must abscise before the bud can develop, the same as in atemoya and

cherimoya.

126 Chapter 6

frequently separate, exposing the white ﬂ esh upon ripening (Fig. 6.2). The

fruit matures during the summer although production can extend for several

months.

Atemoya is a hybrid between A. squamosa and A. cherimola; P.J. Wester

of Florida produced the ﬁ rst hybrids in 1908 and called it the ‘atemoya’,

using the Brazilian name ‘ate’ for sweetsop and ‘moya’ from cherimoya. In

1927, hybrids were also developed in Poona, India. Numerous cultivars have

been selected in Israel (Gazit and Eistenstein, 1985). There is considerable

variation among seedlings. Leaves are glabrous and larger than those of the

parents, with ﬂ owering and fruiting seasons resembling those of A. squamosa.

Seedlings also di er widely in the external and internal structure of the fruit.

Favourable characteristics inherited from the cherimoya parent include

many seedless carpels and carpels that adhere together instead of breaking

apart into individual tubercles, as in the sweetsop (Fig. 6.2). The atemoya is

more tropical in its requirements than cherimoya. While young trees require

some protection from frost, older trees have shown tolerance in Australia.

The atemoya is currently grown commercially in Israel, Australia, California,

Florida and Hawaii and in other countries for domestic consumption.

A. glabra L. (pond apple) has greater potential as a rootstock than for

fruit. It grows wild in southern Florida around lakes and rivers and is widely

distributed in the lowlands of tropical America. It is a vigorous grower,

reaching heights of 12 m and grows well in swampy areas. The ﬂ ower is

fragrant, creamy-yellow and reddish inside. The fruit is about the size of the

sweetsop and heart-shaped; its yellow pulp is described as insipid.

Fig. 6.2. Fruit of sweetsop and atemoya.

Annonas: Cherimoya, Atemoya and Sweetsop 127

ECOLOGY

Soil

All species are capable of growing in a wide range of soil types, from sandy

soil to clay loams. Nevertheless, they di er in their soil preferences. Higher

yields occur on well-drained sandy to sandy loam soils, except in the case of

A. glabra, which can succeed in shallow ponds. Drainage is essential to avoid

root-rot diseases; hence the interest in A. glabra as a rootstock, related to its

tolerance of wet soils. Cherimoyas and atemoyas prefer sandy or sandy loam

soils with uniform moisture but with a good drainage to avoid root rots, and

a dry period at the end of winter at the time of leaf fall will enhance ﬂ owering

uniformity. Sweetsop is capable of growing in a wide range of soil types, but its

shallow root system does not allow for ﬂ ooded or waterlogged soils. It will do

best if good drainage exists and if soil pH is around 5.8–6.6.

Rainfall

In cherimoya and atemoya, rainfall and high humidity during the peak

ﬂ owering season greatly enhance fruit production by preventing desiccation

of stigmas, prolonging their receptive period and increasing fruit set and early

fruit growth. Similar conditions are also ideal for other Annonas. The sweetsop

is probably the most drought-tolerant species and it grows and produces poorly

where rains are frequent. For example, sweetsop does much better in northern

Malaysia, where dry periods occur, than in the southern part, which has year-

round high moisture. For cherimoya and atemoya, a dry period at the coldest

time of the year enhances leaf fall and ﬂ owering at the end of spring and early

summer. This dry period is not required for sweetsop.

Temperature

Temperature is the limiting factor, with frost killing young trees, especially

sweetsop, but older trees showing some tolerance. Cherimoya (7–18°C

mean minimum) is more tolerant to low temperatures (Fig. 6.3), followed

by atemoya (10–20°C mean minimum). Cherimoya can initiate vegetative

growth at ~7°C, while atemoya starts at ~10°C. Except for cherimoya, the

annonas do not require chilling periods and do well under lowland conditions

(George and Nissen, 1987b). Cherimoya is susceptible to high temperatures,

with a growing temperature range of 21–30°C (George and Nissen, 1986b).

Both cherimoya and atemoya are semi-deciduous, and growth declines at

128 Chapter 6

the end of winter and the beginning of spring, during which many leaves

fall, followed by ﬂ owering by the end of spring. In areas with year-round good

growing temperatures and no dry period, atemoyas can be forced to complete

their ﬂ owering and fruit cycle in 8 months. An 8-month fruit cycle allows for

three harvests in 2 years. To achieve three cycles in 2 years requires careful

management of irrigation, fertilization, pruning and defoliation.

Poor pollination is a frequent problem with all three species and

occurs under high temperature (30°C) and low humidity (30% RH).

Lower temperature (25°C) and high humidity (80% RH) greatly improves

pollination. Hand-pollination is recommended for cherimoya and atemoya to

achieve more uniform fruit shape (Fig. 6.4). Sweetsop exposed to >30°C and

relative humidity <60% leads to poor pollination, even if hand-pollinated.

At 25°C and a relative humidity >80% sweetsop pollination is greatly

improved, with too high RH and rain negatively a ecting anther dehiscence.

High temperatures will induce strong vegetative growth in atemoya and

cherimoya. A temperature of 22–28°C is ideal for fruit set in atemoya, while

cherimoya needs slightly lower temperatures for fruit set.

Australia (max.)

Thailand (max.)

Thailand (min.)

Spain (max.)

Spain (min.)

Temperature (ºC)

JFMA ASONDMJJ

Month

Australia (min.)

Fig. 6.3. Seasonal changes in mean monthly minimum temperature for areas suited

to sweetsop (Bangkok, Thailand), atemoya (Mareeba, Australia) and cherimoya

(Malaga, Spain) in southern-hemisphere equivalents (after Marler et al., 1994).

Annonas: Cherimoya, Atemoya and Sweetsop 129

Light and photoperiod

Light penetration to the base of vigorous atemoya trees with a dense canopy

in close spacing can be 2% of full sunlight, and there is very little fruit set.

Pruning practices and spacing need to be adjusted for this shading e ect on

growth. No photoperiod responses have been reported. All three species need

some sort of pruning to obtain better light penetration into the canopy.

Wind

The soft wood of the trees makes them susceptible to wind damage and limb

breakage. Tree shaking may also be partially responsible for the penetration of

collar-rot organisms. The fruit skin is easily damaged by rubbing and exposure

to drying winds, leaving black scars. Annona leaf stomata are very sensitive

to changes in RH and rapidly close in response to declining RH (Marler et al.,

1994). Productivity can be improved by windbreaks and under-tree sprinkling

to raise the RH above 60%.

Fig. 6.4. Hand-pollination of atemoya using a hand-blower to disperse the pollen

collected the day before on to the open ﬂ ower (courtesy of R. Manshardt).

130 Chapter 6

GENERAL CHARACTERISTICS

Flowers

The ﬂ owers of Annona species are hermaphroditic and are produced singly

or in small clusters in a compound inﬂ orescence on an enlarged receptacle.

Flowers arise on the current season’s growth and occasionally on old wood.

Cherimoya and atemoya ﬂ owers are fragrant and are solitary or in groups of

two or three on short, hairy stalks. The ﬂ owers are multi-staminate and multi-

pistilate. New ﬂ owers continue to appear towards the apex of the shoot as

ﬂ owers produced earlier at the basal portions mature (Fig. 6.5). Defoliation of

cherimoya or atemoya manually or by using ethephon spray promotes lateral

branch growth and induces additional ﬂ ower formation, since it exposes the

buds covered by the petiole base.

Annona species generally require 27–35 days for ﬂ ower-bud development

from initiation to anthesis. Di erences in ﬂ oral behaviour in the various

areas may be attributed to both genetic variability and climatic di erences

(Kshirsaga et al., 1976). Flowering can extend from 3 to 6 months or even

longer, with heavy peaks. In sweetsop, two major ﬂ owering periods occur after

periods of vegetative ﬂ ushes, with the second peak coinciding with the onset of

the monsoon in India (Kumar et al., 1977). Atemoyas in Australia produce the

Mean weekly shoot increment (cm)

02468

Weeks from the start of bud break

10 12 14

Flowers set

Flowers

Shoot

Total number of flowers/tree/wk and % set/wk

Fig. 6.5. Atemoya: newly emerging vegetative-ﬂ ush shoot increment, total number

of ﬂ owers produced per week and percentage ﬂ owers set per week. Peak fruit set

occurs after completion of vegetative ﬂ ush (after George and Nissen, 1988).

Annonas: Cherimoya, Atemoya and Sweetsop 131

ﬁ rst ﬂ owers during spring and have a second ﬂ owering during the summer, the

latter being the more productive (Sanewski, 1991).

Pollination and fruit set

Natural pollination

The ﬂ owers exhibit both dichogamy and a protogynous nature. This poses

a serious problem in obtaining high yields. The ﬂ owering seasons of A.

squamosa and A. cherimola coincide. When sweetsop pollen is shed at about 2

a.m., cherimoya ﬂ owers are receptive, opening around 7–9 a.m. and, when

cherimoya pollen is shed at 3–6 p.m., sweetsop ﬂ owers are receptive. This

ﬂ ower synchrony, together with complementary functional sexes, favours

cross-pollination, leading to natural hybridization. This is attested to by the

frequent appearance of hybrid seedlings under the trees of sweetsop and

cherimoya when grown in close proximity. Sweetsop is a more e ective pollen

source than cherimoya in cross-combination studies.

The atemoya female parts are receptive between 4 p.m. and 8 a.m.

and appear moist and sticky (Thakur and Singh, 1964). Atemoya pollen

is discharged in the afternoon of the same day from 3 to 6 p.m., if the RH is

above 80% and the temperature >22°C. At lower temperatures, pollen is

released on the afternoon of the second day. The pollen sacs turn a greyish

colour as pollen is discharged. Pollen grains from ﬂ owers that appear early in

a ﬂ owering season have thick walls, are high in starch, germinate poorly and

give poor fruit set. Pollen of later ﬂ owers shows a high proportion of individual

pollen grains without starch grains, which germinate well. Upon opening,

ﬂ owers are receptive for about 24 h. It has also been shown that spraying the

ﬂ owers with water or putting a drop into the ﬂ ower can signiﬁ cantly increase

fruit set, probably because of the increased humidity slowing the drying of the

stigma and pollen grains. Night-time irrigation with micro-sprinklers or late

afternoon rains also increases fruit set.

Nitidulid beetles (Carpophilus and Uroporus spp.) are the important

pollinators of Annona ﬂ owers, with wind- and self-pollination being low

(1.5%). Fruit set of ‘African Pride’ atemoya increases linearly with increasing

numbers of nitidulid beetles per ﬂ ower. Three or more beetles per ﬂ ower

increased fruit set to nearly 25%. Studies also show that these beetles breed

rapidly in rotting fruit media and that their populations can be increased by

maintaining a rotting-fruit attractant.

Hand-pollination is frequently practised to ensure pollination and good

fruit shape. Pollen must be collected in the evening from fully open ﬂ owers,

when the sacs have turned from white to cream. The ﬂ owers are held in a

paper bag, not a closed container, and should discharge that afternoon. The

ﬂ owers are shaken over a shallow tray or paper to collect the pollen, which is

transferred to a small container and held in the refrigerator for use the next

132 Chapter 6

morning. Twenty to 30 ﬂ owers can give enough pollen to pollinate 50–60

ﬂ owers. Pollination is done daily, using a small (No. 4) organic hair brush,

so that pollen adheres better to it, or a pu er (Fig. 6.4). Pollen diluted with

Lycopodium spores (1:1 dilution) allows pollination of more ﬂ owers. About

150 ﬂ owers can be pollinated in 1 h, with a success rate of 80–100% being

achieved.

Hand-pollination is less successful when carried out on very humid,

overcast days and on young vigorous trees. In Honduras, hand-pollinatation

of ‘Gefner’ atemoya was better when done between 4.00 and 6.00 p.m.

than between 6.30 and 8.30 a.m. when the day temperatures were ~30°C

and relative humidity was low (Duarte et al., 1997). A fruit set of ~47% was

obtained against ~12% for morning pollination. This result was probably

obtained because of the lower night temperatures and higher humidity and the

use of pollen collected in the ﬁ eld and applied immediately. When the Peruvian

‘Cumbe’ cherimoya was grown in Honduras, better fruit set was obtained

using pollen from a di erent variety (‘Bronceada’ from Chile) and afternoon

pollination rather than pollination in the morning (Duarte and Escobar, 1994).

Growth regulators for fruit setting

Hand-pollination in commercial orchards is tedious, time-consuming and

a costly practice. Attempts have been made to use growth regulators, with

considerable variation in the results obtained. Auxin-induced (indole acetic

acid (IAA), naphthalene acetic acid (NAA)) fruit grow very slowly with

less fruit drop, while gibberellic acid (GA

) promotes fruit set and growth;

however, it does not aid in early fruit retention (Duarte et al., 1974a; Yang,

1988). Application of the two substances separately at appropriate times has

produced seedless fruit of 200–300 g (Saavedra, 1979). Gibberellin (1000

ppm) is more e ective than hand-pollination and produced seedless fruit in

atemoya cultivars ‘African Pride’ and ‘Gefner’. Repeated spraying is necessary

to prevent fruit abscission during the ﬁ rst 2 months. Seedless fruit are smaller,

with less ﬂ avour and less fruit splitting than occurs in the seedy fruit that

result from pollination (Yang, 1988). Similar results have been obtained

for cherimoya and sweetsop. GA spraying is not recommended as a general

management practice for atemoya, because of variable results, although it

could be used in areas with poor natural pollination.

Fruit

Fruits of cherimoya, atemoya and sweetsop are compound fruits, generally

conical or roundish or heart-shaped. Cherimoyas can weigh up to 1000 g,

with an average of about 150–500 g, while atemoyas and sweetsops are

smaller. The skin can be smooth with ﬁ ngerprint-like markings or can be

Annonas: Cherimoya, Atemoya and Sweetsop 133

covered with conical or rounded protuberances. The mature fruit is soft and

can easily be opened to show its white, juicy ﬂ esh, of pleasing aroma and

subacid ﬂ avour, containing numerous – sometimes few – brown or black, hard

and glossy, bean-like seeds. Atemoya has smaller seeds, while sweetsop has the

largest seed number.

Fruit growth shows the typical sigmoidal curve, with maturation

occurring in 16–24 weeks, depending upon species and growing conditions

(Fig. 6.6). Low humidity (<60% RH) and temperature (<13°C) near fruit

maturity can increase the severity of fruit skin russeting, as well as delaying

fruit maturation. High temperature can cause premature fruit ripening and

fermentation of the fruit.

CULTIVAR DEVELOPMENT

Genetics, cytogenetics and breeding

The chromosome numbers of A. cherimola, A. reticulata, A. squamosa and

atemoya are 2n = 14. A. glabra has been shown to be a tetraploid (2n = 28),

Fig. 6.6. Increase in fruit diameter from anthesis for sweetsop and cherimoyas (after

Thakur and Singh, 1965).

Weeks from anthesis

134 Chapter 6

and the occurrence of high chiasma frequency and the absence of multivalents

during meiosis suggest that it is of amphidiploid origin.

Cross-pollination between species is conducted primarily to determine

compatibility for increasing fruit set. Atemoya is the only hybrid that has

gained importance and it has inherited the glabrate leaf character of A.

squamosa and a leaf size almost as large as that of A. cherimola. Flowering and

fruiting seasons are similar to those of sweetsop. Skin, pulp and seed characters

of both parents are inherited in varying degrees by each plant. A desirable

hybrid would be between the cherimoya and soursop that combines the larger

fruit size and acidity of the soursop and the cherimoya’s sweetness, ﬂ avour and

texture. Attempts to cross the soursop with cherimoya, ilama, bullock’s heart

or sweetsop have not been successful and may reﬂ ect a considerable genetic

distance of soursop from the other species (Samuel et al., 1991).

Problems in breeding

The long reproductive cycles, higher levels of heterozygosity and the costs

associated with evaluating large populations of crosses limits breeding

programmes. Existing commercial cultivars show considerable variation in

growth, fruit set, fruit size and quality. No single variety has all the desirable

characteristics. The length of the juvenile period varies, with earliest

production occurring in 2 years and full production in 5–6 years. This

juvenile period is extremely variable with scions on seedling rootstocks. The

seedling rootstocks are derived from extremely heterogeneous, open-pollinated

seeds; hence it is di cult to ﬁ x speciﬁ c characters in a short period. Breeding

programmes have focused on selections from seedling populations. Early

maturity, better fruit appearance and, in the subtropics, greater cold tolerance

are the most frequent objectives.

Cultivar development

Except for cherimoya and atemoya, very few named clonal cultivars have been

developed among the Annonas (Table 6.1). Most of the plantings have been of

seedlings. In California, some old cultivars of cherimoya include ‘McPherson’,

‘Deliciosa’ and ‘Bays’. Considerable work has been done in Peru on the

development of cultivars, but they are not widely known outside Peru; one of

them, ‘Cumbe’, is considered exceptional, because of size, surface smoothness,

ﬂ avour and very few seeds. Chile, Spain and New Zealand grow the cherimoya,

as it is more tolerant of cold temperatures, with more successful self-pollination

than the atemoya. New Zealand’s principal cultivars are ‘Reretai’, ‘Burton’s

Wonder’ and ‘Burton’s Favourite’. Chilean cultivars ‘Bronceada’ and ‘Concha

Lisa’ have also performed well in Australia, the former having been reported to

Annonas: Cherimoya, Atemoya and Sweetsop 135

possess a postharvest cold-storage life of 3 weeks. Pascual et al. (1993) report

seven cherimoya cultivars in Spain, of which ‘Fino de Jete’ and ‘Campa’ are

the most extensively cultivated, due to their superior yield and quality. Isozyme

studies indicated that these two cultivars showed identical banding patterns

for 15 enzymes, indicating that they were most probably the same cultivar. A

cluster analysis of isozyme patterns showed that Spanish cherimoya cultivars

were distinctly di erent from cultivars in California (Pascual et al., 1993)

and atemoya (Ellstrand and Lee, 1987). Spain has focused its programme on

germplasm collection and in situ evaluation. Similar programmes are taking

place in Mexico and Chile. In Spain polymorphic molecular markers are being

developed for cherimoya, most of which can be transferred to other Annonas.

Six atemoya cultivars have been described in Australia (Sanewski, 1991).

‘Pink’s Mammoth’ is reported to have been introduced from British Guiana

to Australia. It takes 6–7 years to begin producing commercial-size yields of

fruit, which are large, weighing from 800 g to as much as 2 kg, and it is a less

precocious bearer than ‘African Pride’. ‘African Pride’ was probably introduced

into Australia from South Africa, although its origin may have been Israel.

Table 6.1. Selected cultivars of cherimoya and atemoya.

Cherimoya Atemoya

Name Origin Name Origin

Andrews Australia African Pride Southern Africa or

Israel

Bays USA – California Bradley USA – Florida

Booth USA – California Gefner Israel

Bronceada Chile Island Gem Australia

Burton’s Wonder New Zealand Kabri Israel

Campa Spain Malalai Israel

Concha Lisa Chile Nielsen Australia

Cristalino Spain Page USA – Florida

Cumbe Peru Pink’s Mammoth Australia

E-8 Ecuador

Fino de Jete Spain

Kempsey Australia

Libby USA – California

Lisa USA – California

Mossman Australia

Negrito Spain

Reretai New Zealand

White USA – California

136 Chapter 6

It produces good yields of small to medium-sized fruit. ‘Bullock’s Heart’ (an

atemoya) is similar to ‘Pink’s Mammoth’. ‘Island Gem’ is an early-maturing,

small-fruited, heavy yielder. Two new cultivars developed in Australia are

‘Maroochy Gold’ and ‘KJ Pinks’, which have superseded the old, above-

mentioned cultivars (George and Paull, 2008). In Florida they developed the

cultivars ‘Bradley’ and ‘Page’. The former produces small-sized fruit with

relatively smooth and thin skin. The latter produces medium-sized, well-

shaped fruit with prominent skin segments. ‘Gefner’, an Israeli cultivar, is the

main cultivar grown in Florida and Hawaii; it produces small to medium-sized

fruit resembling ‘Page’.

In order to develop cultivars adapted to cooler environments, Australia

has concentrated on self-progenies and interspeciﬁ c crosses of A. cherimola

with A. reticulata and A. diversifolia. Progenies of A. cherimoya–A. reticulata

crosses are late-maturing, showing ﬂ owering and fruiting characteristics of

A. reticulata, which ﬂ owers in the autumn and has mature fruit in late spring.

Selections possessing most of the fruit qualities of commercial cultivars have

been established in various areas for evaluation.

India and Taiwan have produced a few named cultivars of A. squamosa

that are propagated vegetatively. The main Taiwan cultivars are ‘Ruan-zhi’,

‘Cu-lin’, ‘Da-mu’, ‘Tainung no. 1’ and ‘Xi-lin’. Indian cultivars include ‘Arka

Sahan’, ‘Barbadose Seedling’, ‘Washington’, ‘Red Sitaphal’, ‘Balanagar’,

‘Mammoth’, ‘Purandhar’ and ‘Arka’. Thailand has developed ‘Fai Kaew’, ‘Fai

Krung’, ‘Nang Kaew’, ‘Nang Sir Krung’ and ‘Nang Thong’. In Florida they

selected ‘Lessard’, ‘Kampong Mauve’ and ‘Red Sugar’, and they also plant

‘Cuban Seedless’, a cultivar developed in Cuba that is seedless with medium-

sized fruit; there is another Cuban cultivar that is low in ﬁ bre content. Seedling

populations have been established in Taiwan to select superior lines with

better yield, quality, early maturity and higher edible ﬂ esh ratio and better

postharvest behaviour (Chen and Paull, 2008).

CULTURAL PRACTICES

Propagation

The Annonas, except for the cherimoya and atemoya, are usually propagated

by seed (George and Nissen, 1987b). There is a rapid loss of seed viability (6

months), and seeds should be planted as soon as possible after removal from

the fruit. Cherimoya seeds can take up to 30 days to germinate, and GA

treatment (10,000 ppm) can signiﬁ cantly increase germination and enhance

seedling growth (Duarte et al., 1974b). Seedlings require at least 3–4 years to

bear fruit (Sanewski, 1991). In some seed lots, germination occurs quickly,

while in other lots it can take several months; therefore ideally it is better to

use fresh seeds in all Annonas.

Annonas: Cherimoya, Atemoya and Sweetsop 137

Clonal propagation by cuttings, layering, inarching, grafting and budding

have been tried (Table 6.2). Inconsistent results have been obtained with

cherimoya when 1-year-old cuttings are treated with rooting hormones, and

cuttings from mature trees have been di cult to root (Duarte et al., 1974b).

Atemoya, as a hybrid, has to be propagated asexually by cuttings from selected

trees or grafting or budding. There are cultivar di erences in the rooting ability

of atemoya, with ‘African Pride’ having a higher rooting response (60–80%)

than ‘Pink’s Mammoth’ and cherimoya (<20%). Atemoya tip cuttings are

superior to stem cuttings, with rooting percentages between 50 and 60%,

as compared with about 25% for stem cuttings (Sanewski, 1991). Time of

cutting removal is crucial for success, cuttings taken at the end of the cool

season showing the greater success. Roots should occur in 8–12 weeks and

the cuttings are ready to pot in 16–20 weeks. Air-layering can be used with

some cultivars, although cherimoya is not propagated easily. A modiﬁ cation

where the new shoot is clamped and only the shoot tip is exposed is successful.

Inarching of A. squamosa, A. cherimola, A. glabra and atemoya to A. reticulata

rootstock has been successful, with only A. glabra giving less than 70% success.

Although inarching has given good results, it is time-consuming and costly for

large-scale propagation (George and Nissen, 1987b).

Cherimoyas are normally grafted or budded. Grafting is superior to budding

in percentage takes and subsequent growth, with side-whip graft and cleft-

graft techniques giving the best results (Duarte et al., 1974b). The branches

should be defoliated 1–2 weeks before scion wood is cut to induce bud swelling.

T-budding and chip-budding methods are successful. There are considerable

graft incompatibilities among Annona (Table 6.3) and Rollinia species and types.

Cherimoya has been found to be a vigorous rootstock for ‘Pink’s Mammoth’

(atemoya), although atemoya is not compatible with A. glabra, A. montana,

Table 6.2. Propagation methods and success for Annona spp. (after George and

Nissen, 1987b). Root-cutting success rate is unknown.

Method Species

Atemoya Sweetsop Cherimoya

Seedling

Genetically Variable Uniform Variable

Use Not recommended Good Rootstock

Tip and stem cutting Some cvs only Some cvs only Not successful

Micropropagation Possibly high Unknown Unknown

Layering Unknown High if modiﬁ ed

techniques used

Unknown

Air-layering <5%

<8.3%

<5%

Budding >70% >70% >70%

Grafting >70% >70% >70%

138 Chapter 6

Table 6.3. Rootstock and scion compatibility of different Annonas (after Sanewski, 1991).

Scion

Rootstock Atemoya Gefner

Pink’s

Mammoth Page/Bradley A. cherimola A. glabra A. muricata A. squamosa

Atemoya C C

–– C

Gefner C

Pink’s Mammoth C

Page/Bradley C

A. cherimola

CC CC

–

A. glabra

N–CC–

A. muricata

N–CCN

A. palustris

––––N

A. reticulata

NPC C P – C

A. squamosa

CC––C

C, compatible; P, partial; N, not compatible; –, unknown.

Annonas: Cherimoya, Atemoya and Sweetsop 139

A. muricata and A. reticulata as rootstocks (Sanewski, 1991). This is complicated

by cultivar di erences in compatibility with common rootstocks. Atemoya

cultivars ‘Bradley’ and ‘Page’ are compatible with custard-apple rootstocks, but

‘Gefner’ shows partial incompatibility with the same rootstock (Table 6.3).

Sweetsop is usually seed-propagated. The seeds should be sown within

a week after extraction from the fruit. Inarching can be done to A. reticulata,

with 70% success (George and Nissen, 1987b). The same success is obtained

for grafting and budding. Rooting of tips has been successful in some cases, as

well as air layers, but they are more costly.

Rootstocks

There are several possible combinations and incompatibilities among Annona

and Rollinia species. Cherimoya rootstocks normally include seedlings of

cherimoya and, in some cases, soursop and sweetsop. For atemoya, cherimoya

and atemoya are normally used as rootstocks and also A. squamosa, but it is

susceptible to bacterial wilt caused by Pseudomonas solanacearum. Sweetsop

is normally not grafted or budded, but it could be done with seedlings of

sweetsop, cherimoya or A. glabra (Table 6.3). A. muricata or Annona palustris

are not good rootstocks for sweetsop.

Field preparation

A soil sample should be taken 4–6 months before planting to determine lime

requirements and soil nutrient levels. Soil phosphorus can also be adjusted

at this time or in the planting hole. Minimal tillage can be achieved with a

2-m-wide band cultivated where the trees are to be planted. Drainage should

be installed at this time to avoid ﬂ ooding, with either contour or subsurface

drains. Windbreaks should be established prior to transplanting. Napier or

Bu alo or Bana grass (Pennisetum purpureum Schumacher) can be used when

shelter is required in the ﬁ rst 12 months.

Transplanting and spacing

Transplanting should be done at the beginning of the wet season if there are

seasonal dry periods and no irrigation facilities. In the subtropics, planting

should not occur if there is a risk of frost. Plants should have attained a height

of 30–50 cm at transplanting time, with the union of grafted or budded plants

placed 15 cm or so above the ground. Trees should be irrigated as soon as

possible after transplanting, with wind and sun guards sometimes required.

140 Chapter 6

Transplanting distance depends upon the species of Annona. The

periodically pruned small sweetsop can be spaced at 3.7 m × 4.6 m. In dry

areas with less luxuriant growth, closer within-row spacing than 3.7 m can be

considered. Closer spacing would increase humidity and beneﬁ t the longevity

of stigma receptivity. For machine operations, wider spacing of 5.0–5.5 m ×

6.0–6.5 m can be used.

Cherimoya can be planted at 5 m × 6 m within and between rows, with

appropriate pruning practices. Row spacing of 5–10 m and between rows

7–12 m are recommended for atemoya in Australia, depending on cultivar,

rootstock and pruning to an open goblet. Narrower spacing is used for

‘African Pride’ on A. squamosa rootstock, and the widest spacing is for ‘Pink’s

Mammoth’ on A. cherimola. In Florida, narrow plant spacing of 4–6 m and

row spacing of 6–7 m are used (Campbell, 1985). A triangular layout is

recommended whatever planting distance is selected, with the rows running

north–south to avoid shading. In Chile, narrow spacing (4 m × 2 m) has been

tried for cherimoyas, and there are some commercial plantings that use 5 m ×

1.5 m (Gardiazabal and Rosenberg, 1993). Some experimental trellis plantings

also exist.

Irrigation practices

The Annonas are grown in many areas without irrigation when rainfall is

well distributed. Except for pond apple (A. glabra), most Annonas can stand

periods of drought and prefer rather dry conditions. There must be adequate

soil moisture to encourage vegetative growth, since ﬂ owering occurs on new

growth. Bearing atemoya trees may need up to 1440 l/tree every 4 weeks

during the low-growth phase and from 500 to 750 l/tree every 3–5 days

during ﬂ owering, fruit set and fruit growth (Sanewski, 1991). Reducing

irrigation in late winter to force atemoya and cherimoya trees into dormancy

for 1–2 months in spring is recommended in Australia and California,

respectively. The amount and frequency of irrigation must be determined by

experience in any particular location and soil type. Water stress should be

prevented during ﬂ owering, fruit set and fruit development, as fruits are more

sensitive than leaves to water stress (Fig. 6.7).

High soil moisture to increase humidity during the ﬂ owering season

may prolong stigma receptivity and fruit set and growth. The use of low-

rise sprinklers under the tree canopy during ﬂ owering increases the canopy

humidity. The stomata of Annona respond to RH, not water stress, and will

continue to lose water if the humidity is greater than 80%, making it crucial

to maintain soil moisture content (Marler et al., 1994).

Annonas: Cherimoya, Atemoya and Sweetsop 141

Pruning

Training of trees should begin in the nursery, and pruning should continue

after transplanting. It is desirable to train the tree to a single trunk up to a

height of about 90 cm and then it should be headed back to produce lateral

branches. The lateral branches should be spaced 15–25 cm above each other

and be allowed to grow in di erent directions to develop a good sca old. After

about 2 m, they can be left to natural growth. Pruning is carried out when

the trees are dormant and, in heavy trees, involves removal of lower limbs

touching the ground and branches in the centre that may be rubbing against

each other. The objective is to allow sunlight access to the centre of the tree

(George and Nissen, 1986a).

All lateral buds can have up to two vegetative buds and three ﬂ ower buds.

The lateral buds of atemoya, cherimoya and sweetsop are normally ‘buried’

(subpetiolar) in the base of the swollen leaf petiole (Fig. 6.1). Leaf shed must

occur prior to the elongation of ‘buried’ buds (George and Nissen, 1987a).

Removal of leaves mechanically by stripping or chemically with urea or

Flowering and fruiting

Harvest

Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec. Jan. Feb. Mar.

Harvest

Pruning

Leaf drop Leaf dropLeaf growth

Flowering

Fruit set

Fruit growth

Harvest

Flower

initiation

Flower

initiation

Pruning

Sweetsop

Atemoya

Pruning

Summer pruning

Winter pruning

Fig. 6.7. Growth and management practices for sweetsop grown in Taiwan (Anon.,

1995) and atemoya (Sanewski, 1991). In Taiwan, normal sweetsop pruning occurs

in January and February, and there are extended periods of pruning of selected trees

in summer. The atemoya cycle has been converted to northern-hemisphere seasons

for comparison purposes.

142 Chapter 6

ethephon releases these buds. The buds in ‘Pink’s Mammoth’ and ‘African

Pride’ are more suppressed and may require leaf stripping in the summer.

Adventitious buds can arise at any point on a trunk.

Atemoya produces the ﬁ rst ﬂ owers of a season and the most ﬂ owers on

1-year-old wood. The second and third ﬂ ushes of ﬂ owers occur on new growth

and produce most of the crop (Fig. 6.5). The ﬂ owers of the ﬁ rst ﬂ ush may be

removed, as they show poor fruit set and have greater problems with fruit

splitting upon ripening. In south-east Queensland, each year the 1-year-old

fruiting wood is shortened to about 10–15 cm, with four to six buds (Sanewski,

1991). These pruned laterals are retained after producing fruit and allowed to

become part of the framework, thus extending the canopy by 30–50 cm each

year. However, dense shading within the canopy is a major problem. The open-

goblet system is used to produce an open, spreading tree that will produce fruit

early and avoid dense shading. The strategy is to produce one or two fruits on

each shortened, 1-year-old lateral. These laterals are removed completely after

2–3 years and replaced by new growth closer to the leader. The ideal seasonal

growth of laterals producing fruit is about 60 cm long and about 10 mm in

diameter at the base. Annual lateral growth more than 100 cm is considered

excessive for mature fruiting trees. This system allows the development of

fruiting laterals along all the main limbs, with a moderately open centre,

although trees under this system rapidly grow tall. Pruning is normally

carried out in spring before large amounts of bud growth have occurred, with

a moderate summer pruning. Defoliation during the cool season to allow early

development of the buried buds and more uniform ﬂ owering is sometimes

carried out with an ethephon–urea mixture (Sanewski, 1991). Rejuvenation

by heavy pruning is occasionally needed.

Summer pruning of cherimoya was tried in Chile by removing the shoot

tips, leaving six or ten buds, after artiﬁ cial pollination had been performed. In

some cases, girdling or scoring were used in combination. The best treatment

was to cut the shoots at ten buds combined with girdling the trunk during

ﬂ owering time, with an increase of 22% in fruit yield and 25% in fruit weight

(Razeto and Diaz de Valdes, 2001).

Sweetsop is pruned so that 1-year-old branches are cut back to 10 cm.

The pruning left 120–150 branches per tree, with root pruning not being

recommended. Flower initiation begins at the basal end of the growing branch

(Lo, 1987). In Taiwan, normal pruning occurs in January/February, with

fruit harvest from July to September (Fig. 6.7). A summer pruning with fruit

thinning (June–October) of selected trees can lead to harvesting fruit from

October to the next March (Yang, 1987). Highest winter fruiting occurs when

summer growth is pruned, compared with pruning non-fruiting shoots or

pruning in late May.

Annonas: Cherimoya, Atemoya and Sweetsop 143

Fertilization

The Annonas have an indeterminate growth habit (axillary ﬂ owering), and

applying nitrogen (N) in somewhat excessive amounts does not interfere

greatly with ﬂ oral initiation, as is the case with plants having determinate

growth habit. However, excessive tree vigour is usually associated with reduced

ﬂ owering and yields in many tree crops and the atemoyas are no exception

(George et al., 1989).

In Australia, continued research and ﬁ eld observations on atemoya

nutrition have led to greater reﬁ nements in terms of quantity of fertilizer

and times of incremental applications during the annual growth and fruiting

cycles (Table 6.4). The use of foliar nutrient analysis has become a useful

management tool in determining atemoya fertilizer programmes (Sanewski,

1991). Sampling for foliar analysis consists of obtaining the most recently

matured leaf – the fourth or ﬁ fth leaf below the growing point. Leaves are

selected from non-bearing shoots without a leaf ﬂ ush during late summer

or early autumn (Table 6.5). After 10 years of age, the annual amounts of

N, phosphorus (P) and potassium (K) remain the same, as tree size is kept

relatively constant by annual pruning and by competition from adjacent trees.

The annual requirements of N and K are split into four increments (Table 6.4).

In the cool subtropical areas, greatest vegetative growth takes place during the

warmer months, from spring to autumn. Reduction in N during the winter

minimizes new vegetative growth in young trees that are vulnerable to cold

temperatures. This adjustment is not necessary in the warm tropics. P is given

once per year during the early-autumn application.

Table 6.4. A guide to annual application of NPK for ‘Pink’s Mammoth’ atemoya

trees of different ages using straight fertilizers (g/tree/year) and percentage

distribution of application of annual amounts (Sanewski, 1991).

Tree age (years)

Urea

(g/tree/year)

Superphosphate

(g/tree/year)

Potassium chloride

(g/tree/year)

2 400 500 360

4 860 550 930

6 1300 780 1170

8 1600 880 1500

10 1750 880 1650

Fertilizer

Early

spring

Early

summer

Early

autumn

Late

autumn

Urea 20% 30% 40% 10%

Superphosphate 100%

Potassium chloride 10% 30% 40% 20%

144 Chapter 6

The primary sink for K in the atemoya is the fruit, rather than the leaves,

and thus there is a high requirement, with deﬁ ciency likely. About 60% of

the K requirement is applied during the fruit-development period. Atemoyas

also have a fairly high requirement for magnesium (Mg) and calcium (Ca).

Heavy vegetative growth during the fruit-development period competes for

nutrients such as boron (B) and Ca, resulting in boron-deﬁ cient fruit. Boron-

deﬁ cient fruit develop hard, brown, lumpy tissues around the central core.

Deﬁ ciency in B and, to some degree, Ca is considered a causal factor for these

lumps (Cresswell and Sanewski, 1991). Applying B at a slight excess can be

phytotoxic, especially in sandy soils. A desirable practice is to use organic

fertilizers, with inorganic fertilizer as a supplement to maintain a balance and

to control cropping (Sanewski, 1991).

For sweetsop, a periodic application of NPK is best, split into three parts

applied every 4 months. The early-spring application would include all the P

for the year and 20% of the N and K requirements. In summer, the other 70%

of N and 40% of K are applied, and the rest of K is left for autumn application.

A physiological disorder called black speck is caused by Ca deﬁ ciency, which

is corrected by spraying with a foliar Ca solution. This physiological disorder

causes small, dark spots in the shoulder and waist of the fruit, but it can invade

the whole skin in extreme cases.

Pest management

Diseases

A number of diseases have been reported in the literature (Table 6.6).

Anthracnose, caused by Colletotrichum gloeosporioides (Glomerella cingulata),

Table 6.5. Tentative leaf nutrient standards for atemoya (Pink’s Mammoth) in

Queensland, Australia, presented as a guide (Sanewski, 1991).

Nutrient Acceptable range

Nitrogen 2.5–3.0%

Phosphorus 0.16–0.2%

Potassium 1.0–1.5%

Calcium 0.6–1.0%

Magnesium 0.35–0.5%

Sodium < 0.02%

Chloride < 0.3%

Manganese 30–90 ppm

Copper 10–20 ppm

Zinc 15–30 ppm

Iron 50–70 ppm

Boron 15–40 ppm

Annonas: Cherimoya, Atemoya and Sweetsop 145

is the most serious in areas of high rainfall and atmospheric humidity and

during the wet season in dry areas (Alvarez-Garcia, 1949; Dhingra et al.,

1980). This disease causes twig dieback, defoliation and dropping of ﬂ owers

and fruit. On mature fruit, the infection causes black lesions.

Black canker (Phomopsis anonacearum) and diplodia rot (Botryodiplodia

theobromae) occur mostly on neglected trees and cause similar symptoms of

purplish to black lesions, resulting in mummiﬁ ed fruit. Marginal leaf scorch is

also caused by these two fungi and causes twig dieback. Diplodia rot has darker

internal discoloration and deeper, more extensive, corky rot in fruit. A fruit

and leaf spot is caused by a soil-borne fungus, Cylindrocladium colhounii, which

can cause almost total loss of fruit during years of persistent heavy rains.

Symptoms begin with small, dark spots, primarily on the shoulders of the fruit,

which spread along the sides, enlarge, become dry and crack. Infection is skin

deep, but fruit becomes unmarketable. The control measures recommended

are good orchard maintenance with heavy mulching and lower-branch

pruning to prevent splashing of soil during heavy rainfall (Sanewski, 1991).

Bacterial wilt of atemoya is caused by P. solanacearum and is characterized

by rapid wilting and death of young trees and slow decline of old trees. There

is a general decline of vigour and defoliation on a ected limbs. Vascular

discoloration of woody tissues occurs in the roots and up to the trunk at

ground level. It has caused up to 70% tree death in 12 years in orchards using

A. squamosa rootstocks in Queensland.

In sweetsop, Phytophthora blight (purple blotch) is caused by Phytophthora

citrophthora and Phytophthora nicotianae, which infest fruit and leaves, mainly

Table 6.6. Major diseases of Annonas.

Common name Organism Parts affected, symptoms

Region or

country

Anthracnose

Colletotrichum

gloeosporioides

(Glomerella)

Flowers, fruit, leaves,

dieback, seedling

damping off

Universal

Armillaria root

rot

Armillaria

leuteobubalina

Roots, base of trees,

decline

Australia

Bacterial wilt

Pseudomonas

solanacearum

Tree wilt Australia

Black canker

(diplodia rot)

Botryodiplodia

theobromae

Leaf scorch, twig dieback Universal

Black canker

Phomopsis

Leaf scorch, twig dieback Australia

Purple blotch

Phytophthora palmivora

Spots on immature fruit,

fruit drop, twig dieback

Australia

Rust fungus

Phakopsora cherimoliae

Leaves Florida

Fruit rot

Glioclacium roseum

Fruit India

146 Chapter 6

during the wet season; the fruits get mummiﬁ ed and stay on the tree or drop,

and the infected leaves show water-soaked spots that turn brown-black.

Another sweetsop fruit disease is attributed to Gliocladium roseum, which

a ects 20–90% of the fruit in India. Symptoms consist of water-soaked

spots, which turn soft and brown. There is also a bacterial wilt caused by P.

solanacearum that produces a rapid wilting and death of young trees and slow

decline of old trees. Vascular discoloration occurs of woody tissues of the roots

up to the trunk at ground level.

INSECT PESTS

Some insect pests occur in numerous growing areas (Table 6.7). One of the

most serious insects in Trinidad is the Cerconota moth, which lays its eggs on

young fruit. The emerging larvae tunnel into the pulp, causing blackened,

necrotic areas. It is common to ﬁ nd every fruit larger than 7.5 cm infested.

Table 6.7. Major insect pests of Annonas.

Common name Organism Parts affected Country/region

Bephrata wasp

(soursop wasp)

Bephrata maculicollis

Fruit Mexico, Americas,

Trinidad,

Surinam

Wasp

Bephratelloides

paraguayensis

Fruit Americas,

Barbados

Cerconota moth

(soursop moth)

Cerconota annonella

Fruit Americans,

Trinidad,

Surinam

Thecla moth

Thecla ortygnus

Flowers, young

fruit

Americas,

Caribbean

Banana spotting bug

Amblyphelta

lutescens

Young fruit Queensland

Mealy bug

Dysmicoccus spp.

Stem, leaves Universal

Citrus mealy bug

Planococcus citri

Fruit Queensland

Southern stink bug

Nezara viridula

Fruit Caribbean

Caribbean fruit ﬂ y

Anastrepha suspensa

Fruit Caribbean, Mexico

Mediterranean fruit

ﬂ y

Ceratitis capitata

Fruit Peru, Spain

Queensland fruit ﬂ y

Bactrocera tryoni

Fruit Australia

Potato leaf hopper

Empoasca fabae

Leaves Caribbean

Red spider mite

Several genera and

species

Leaves, ﬂ owers American tropics

Scale insects

Saissetia coffeae

Leaves, stem Universal

Coconut scale

insect

Aspidiotus destructor,

other genera and

species

Leaves, stem Caribbean

Annonas: Cherimoya, Atemoya and Sweetsop 147

Bagging the fruit is sometimes done. This moth has been reported in the

American tropics as far south as Brazil and is a major limiting factor in

Surinam (Paull, 2008).

The bephrata wasp (Bephrata maculicollis) is widely distributed throughout

the Caribbean, Mexico, Central America and northern South America. This

wasp is considered to be the most important pest in Florida (Campbell, 1985).

The larvae infest the seeds and cause damage to the pulp, as they bore through

the ﬂ esh to emerge when the fruit matures. The Thecla moth is widespread

through parts of the Caribbean and in the American tropics, but it is not

considered to be as serious as the Cerconota moth and Bephrata wasp. Primary

damage is to the ﬂ owers. The larvae feed on ﬂ ower parts, such as the perianth,

stamens and stigmas, with the ﬂ owers failing to set fruit. Bagging the fruit can

be very e ective and an economic estimate has to be done.

The banana-spotting bug (Amblyphelta lutescens) and the fruit-spotting

bug (Amblyphelta nitida) are considered to be serious atemoya pests. Amblypelta

nitida is rare in northern Queensland, with both being pests in southern

Queensland. The bugs cause small, black, 2–10 mm spots on the shoulders of

young fruit and penetrate about 1 cm into the fruit. The damage resembles the

symptoms of diplodia rot (black canker).

Mature green annonaceous fruits have been shown to be rarely infested

by the Mediterranean fruit ﬂ y (Ceratitis capitata) and Oriental fruit ﬂ y (Dacus

dorsalis), but they are found, on occasion, in tree-ripened fruit. In Peru C.

capitata is one of the most important problems in cherimoya as well as some

Anastrepha species (Franciosi, 1992). Also, in Spain ‘Fino de Jete’, the major

cultivar grown, is very susceptible to the C. capitata fruit ﬂ y. In Australia, the

Queensland fruit ﬂ y (Bactrocera tryoni) infests ripening atemoya fruit. ‘African

Pride’ appears to be more susceptible than ‘Pink’s Mammoth’. Use of bait

sprays and ﬁ eld sanitation are recommended measures to minimize fruit-ﬂ y

infestation (Smith, 1991). Fruit bagging also provides protection.

Mealy bugs and various species of scale insects are found universally and

usually become a serious pest on neglected trees. The former is reported to be

a major pest on marketable fruit in some areas of Australia. Red spider mites

can become a serious problem in dry areas or during dry seasons. Scale insects

are normally a minor problem.

Nematodes can be a problem in some places like Chile, where

Helicotylenchus and Pratylenchus cause signiﬁ cant reduction in plant growth

in certain areas (Gardiazabal and Rosenberg, 1993).

Weed management

Problem weeds, especially grasses and twining weeds, should be controlled by

cultivation and herbicides before planting. Young trees should be protected

from weed competition by hand-weeding, mulching or contact herbicides. The

148 Chapter 6

shallow root systems limit the use of cultivation under the tree. A translocated

herbicide may be needed for perennial weeds and is applied as a spot spray.

HARVESTING AND POSTHARVEST HANDLING

Harvesting season, yield and harvesting

The harvesting season is quite similar in most areas, di ering only in range

(Table 6.8). Sweetsop is usually harvested during the summer months,

from July to November, and can be extended to March (Fig. 6.7). Atemoya is

harvested in autumn in the southern hemisphere and winter in Australia (Fig.

6.7) and from October to January in Poona, India.

A major problem in Annona cultivation is obtaining commercial yields. In

order to increase yield, hand-pollination (Fig. 6.4) has become an important

aspect of cultivation practices in some areas, especially for atemoya. Use of

pollen stored under poor conditions, naturally defective pollen and pollinating

during the hottest period of the day result in very poor fruit set.

Rootstocks have been shown to greatly inﬂ uence yield (Sanewski, 1991).

Trees of the same age and cultivar on cherimoya rootstock yield almost double

that of trees grafted on sweetsop. Cultivar di erences in yield have also been

noted (Fig. 6.8). Estimated yield per tree of 6-year-old ‘African Pride’ on

cherimoya rootstock is about 90 kg, while that of ‘Pink’s Mammoth’ of the

same age and on the same rootstock is about 30 kg. In other cases yields of

80–150 kg/tree

are recorded for cherimoya and sweetsop, equivalent to 15–25

t/ha.

Fruit is harvested when fully mature and ﬁ rm. The skin colour changes

as the fruit approaches maturity. Skin of immature cherimoya and sweetsop

is greyish-green but turns to yellow-green at maturity. In the latter fruit,

Table 6.8. Peak harvesting seasons for some Annona species.

Countries Cherimoya Atemoya Sweetsop

Australia Mar.–Sept.

Argentina Feb.–July

California Mar.–Apr.

Caribbean June–Sept.

Chile Aug.–Dec.

Florida July–Oct. July–Sept. July–Sept.

Hawaii Aug.–Nov.

India (Poona) Nov.–Feb. Oct.–Jan. Aug.–Nov.

Portugal (Madeira) Nov.–Feb.

Annonas: Cherimoya, Atemoya and Sweetsop 149

adjacent carpels towards the blossom end commonly separate, exposing the

white pulp (‘creaming’). ‘Creaming’ between segments of the atemoya fruit is

considered to be an indication of maturity. Fruits are harvested when 40% of

the surface shows ‘creaming’ (Sanewski, 1991). Determining harvest time by

dating ﬂ oral anthesis is impractical, as ﬂ owering occurs over many months. If

a rigid hand-pollination protocol is used, with removal of naturally pollinated

fruit, days from anthesis can be used.

Fruit is hand-harvested and put into lug boxes or baskets. Sometimes

the fruit is harvested using pruning shears, in order to leave a portion of the

peduncle attached to limit stem end rots. Fruit should be harvested preferably

early in the morning, when temperatures are still cool. Atemoyas are

harvested every 3–7 days, with experienced pickers harvesting from 150 to

180 kg fruit/h.

Postharvest handling

Harvested fruit should be handled with care to prevent bruising of the skin.

This is especially important for fruits that are marketed for fresh consumption,

such as cherimoya, sweetsop and atemoya. Fruit of some cherimoya cultivars

can be kept for 7–10 days at 17°C. Normal ripening occurs at temperatures

between 15 and 30°C, and storage temperatures below 15°C cause chilling

injuries and a failure to develop full ﬂ avour, although some Chilean varieties

Fig. 6.8. Approximate yields of two atemoya cultivars, ‘Pink’s Mammoth’ and

‘African Pride’, on cherimoya () and sweetsop (S) rootstocks with tree age (after

Sanewski, 1991).

150 Chapter 6

such as ‘Concha Lisa’ tolerate 7–8°C and ‘Bronceada’ 10–11°C. Fruit

harvested early in the season will have fewer sugars but stores better than

fruit harvested late in the season. Cherimoyas can be coated with di erent

wax formulations to reduce water loss, delay ﬁ rmness and enhance fruit

appearance (Gardiazabal and Rosenberg, 1993).

Storage conditions recommended for sweetsop are 15°C, with an RH of

85–90%. Atemoya fruit can be stored up to 2 weeks at 15–16°C or 1 week

at 10–12°C; fruits stored at 0–5°C turn black. At lower temperatures, skin

discoloration occurs rapidly. Precooling of fruit is essential to help extend

shelf-life. Some trials have been made to store under controlled atmosphere.

Except for the atemoya in Australia, there are no reports of established

grade standards. Australian standards specify mature atemoya fruit should

be 75 mm in diameter, ﬁ rm, with ‘creaming’ between segments on the skin.

Containers are 0.5 bushel (8–10 kg) in size, made of wood, ﬁ breboard or

polystyrene (450 mm × 215 mm × 180 mm), well ventilated and marked with

‘custard apple’ and the number of fruit. The presence of soft fruit and even one

fruit-ﬂ y-damaged fruit can lead to rejection of the consignment.

Compositional changes during fruit ripening

All Annonas are climacteric fruit. Cherimoya has two respiration peaks during

ripening instead of the single peak of other climacteric fruits. The fruits also

seem to release more ethylene than most other fruit and have a higher rate

of metabolism, which shortens its postharvest life. ‘African Pride’ atemoya

respiration reaches a peak about 3 days after harvest, and the eating stage is

reached in another 2 days. Total time from harvest to eating ripeness is about

5 days at 20°C.

UTILIZATION

Cherimoya is a fair to good source of vitamins, while sweetsop is a good source

of P, thiamine and ascorbic acid (Table 6.9). Atemoya is also a good source of

ascorbic acid.

These Annonas are usually consumed as dessert fruit. Once peeled, the

pulp tends to oxidize fairly soon and acquires a brownish colour. Several pies,

custards and ﬁ ne desserts, which can include combinations with whipped

cream and meringues, are made with cherimoya and atemoya. The peeled

pulp can be eaten mixed with orange juice, as they do in Chile. A delicious ice

cream can also be made with these fruits or they can be included in yogurt.

The perishable nature of the fruit and often short supply limits availability to

local markets or air shipment to more-distant markets.

Annonas: Cherimoya, Atemoya and Sweetsop 151

FURTHER READING

Anon. (1995) Production and Marketing of Sweetsop. Special Publication No. l, Taidong

Agricultural Improvement Station, Taiwan (in Chinese).

George, A.P. and Nissen, R.J. (1987) Propagation of Annona species: a review. Scientia

Horticulturae 33, 75–85.

George, A.P., Nissen, R.J. and Brown, B.T. (1987) The custard apple. Queensland

Agricultural Journal 113, 287–297.

George, A. and Paull, R. (2008) Annona squamosa × Annona cherimola, atemoya. In:

Janick, J. and Paull, R. (eds) The Encyclopedia of Fruit and Nuts. CAB International,

Wallingford, UK, pp. 54–62.

Marler, J.E., George, A.P., Nissen, R.J. and Andersen, P.J. (1994) Miscellaneous

tropical fruits – annonas. In: Scha er. B.C. and Andersen, P.C. (eds) Handbook of

Environmental Physiology of Fruit Crops, Vol. II. Subtropical and Tropical Crops. CRC

Press, Boca Raton, Florida, pp. 200–206.

Merodio, C. and De La Plaza, J.L. (1997) Cherimoya. In: Mitra, S.K. (ed.) Postharvest

Physiology and Storage of Tropical and Subtropical Fruits. CAB International,

Wallingford, UK, pp. 265–290.

Paull, R.E. and Chen, N.J. (2004a) Cherimoya. In: USDA Handbook #66. (http://www.

ba.ars.usda.gov/hb66/051cherimoya.pdf, accessed 7 Feb 2010).

Table 6.9. Proximate fruit composition of cherimoya, soursop and atemoya in a

100 g edible portion (after Wenkam, 1990).

Nutrients Cherimoya Atemoya Sweetsop

Water (g) 68.71 78.7 75.97

Energy (kJ) 460 310 360

Protein (g) 1.54 1.4 1.89

Lipid (fat) (g) 0.13 0.6 0.57

Carbohydrate (g) 28.95 15.8 20.82

Fibre (g) – 2.5 1.41

Ash (g) 0.67 0.4 0.75

Minerals

Calcium (mg) 9 17 17

Iron (mg) – 0.3 0.3

Magnesium (mg) – 32 22

Phosphorus (mg) 24 – 54

Potassium (mg) – 250 142

Sodium (mg) – 4 2

Vitamins

Ascorbic acid (mg) 12.20 43 35.9

Thiamine (mg) 0.11 0.05 0.10

Riboﬂ avin (mg) 0.11 0.08 0.06

Niacin (mg) 1.00 0.8 0.89

Vitamin A 0 – 0

Seed/skin % 35.00 28.0 45.00

152 Chapter 6

Paull, R.E. and Chen, N.J. (2004b) Atemoya. In: USDA Handbook #66. (http://www.

ba.ars.usda.gov/hb66/051cherimoya.pdf, accessed 7 Feb 2010).

Pinto, A.C. de Q., Cordeiro, M.C.R., de Andrada, S.R.M., Ferraira, F.R., Filgueiras, H.A.

de C., Alves, R.E. and Kinpara, D.I. (2005) Fruits for the future 5 – Annona species.

Monograph. (http://www.icuc-iwmi.org/ﬁ les/Publications/Annona_Monograph.

pdf, accessed 7 Feb 2010).

Sanewski, G.M. (ed.) (1991) Custard Apples – Cultivation and Crop Protection. Information

Series QI90031, Queensland Department of Primary Industry, Brisbane,

Australia.

(R.E. Paull and O. Duarte)

AVOCADO

The avocado (Persea americana) is the most common English name but it is

also known as alligator pear and butter pear. Spanish-speaking people call it

aguacate, cura or cuprandra, while in Chile, Peru and Educador, it is called by

its Inca name, palta. In French, it is known as avocat and avocatier. The name

‘avocado’ refers to the fruit and is derived from the Aztec Nahuatl language

word, ahuacatl, meaning ‘testicle’. This name is in reference to the shape of

the fruit, which was regarded by the Aztecs as the fertility fruit. The species is

now cultivated worldwide in tropical and subtropical climates.

BOTANY

Family

The laurel family (Lauraceae) is composed of about 55 genera, with more than

2000 species. This basal family in the dicots is in the Order Laurales, which

was sometimes included in the Magnoliales. They are mostly evergreen

trees and shrubs, occasionally aromatic, and native mostly to tropical and

subtropical regions. There are about 150 species of tropical evergreen trees,

many of which are cultivated as ornamentals for their laurel-like leaves.

Important genera and species

The genus Persea Mill. is the best known for the fruit called avocado or

aguacate, P. americana Mill. (Persea gratissima C.F. Gaertn.). The fruits of

most Persea species are small and worthless. Only P. americana and Persea

schiedeana Ness. bear large fruit, the latter species being watery and ﬁ brous

but pleasant in ﬂ avour and eaten by people in its native habitat in Mexico and

Central America. Other species of commercial or ornamental value include

Cinnamomum camphora (L.) Nees and Eberm., camphor tree; Cinnamomum

154 Chapter 7

zeylanicum Breyn., cinnamon tree; Laurus nobilis L., bay or sweet bay; and

Umbellularia californica Nutt., California bay tree.

Origin and distribution

There is general agreement that the centre of origin of the avocado is in the

eastern and central highlands of Mexico and in the adjacent highland areas

of Guatemala to the Paciﬁ c coast. Early European travellers during the 16th

century found avocado in cultivation and distributed throughout Central

America and northern South America. This is evidenced by the native

names given to avocado in many languages and by archaeological ﬁ ndings.

Carbon dating indicates that Mexican avocados were used as food as early as

8000–7000 years ago (Williams, 1976). Separate human selection began

4000–2800  by MesoAmerican Indians, which led to three well-demarcated

ecotypes, known as Guatemalan, Mexican and West Indian (Coastal

Guatemala) (Fig 7.1). These three separate domestications are supported by

ethnobotanical and genetic marker studies (Popenoe, 1920; Ashworth and

Clegg, 2003). The races were separate until after European contact in the 16th

century (Chen et al., 2009).

Early accounts indicate that it was not cultivated in the Caribbean

islands during the pre-Columbian period and was introduced to Jamaica by

Fig. 7.1. Possible evolutionary centres of the three cultivated avocado races

(redrawn from Scora and Bergh, 1992).

Avocado 155

the Spaniards in about 1650. Distribution to the African and Asian tropics

occurred during the 1700s and 1800s. The ﬁ rst recorded importation into

Florida was in 1833, into California in 1848 and into Hawaii during the early

19th century. By 1855, avocado trees were common in gardens of Oahu and

were distributed to the other islands of the Hawaiian chain (Yee, 1978). It is

now widely distributed throughout the tropics and subtropics, but the use of

the fruit di ers in di erent areas. Although the avocado has been available

in most South-east Asian countries, it has not been cultivated widely, due to

a preference for many other fruits. The main producers are Mexico, the USA,

Indonesia, Dominican Republic, Colombia, Chile, Peru and Brazil, with Mexico,

Chile, Israel, Spain and South Africa being the main exporters and Peru trying

to join this group.

The West Indian race is adapted to the humid tropics and is very chilling-

sensitive, with some salinity tolerance. The fruits of the West Indian race

are small with medium-thin, leathery skin; low oil content; loose seed and

maturing 160–240 days after ﬂ owering (Table 7.1). The closely related

Guatemalan race is postulated to have originated at somewhat higher

elevations in Guatemala and adjacent areas, based on abundance of wild

populations (Fig. 7.1). Leaves of cultivated types of this race are not anise-

scented; Popenoe (1920) reported anise-scented wild forms. This race has

some cold tolerance and the fruit has a thick, tough skin that remains green

until maturity. The Mexican race is predominantly found in the higher

Table 7.1. Comparison of selected characteristics of three horticultural races of

avocado (Bergh, 1975; Bergh and Ellstrand, 1986).

Trait West Indian Guatemalan Mexican

Climate Tropical Subtropical Semi-tropical

Cold tolerance Least Intermediate Most

Salt tolerance Most Intermediate Least

Leaf anise Absent Absent Present

Young leaf colour Pale yellow Green with red tinge Green

Mature leaf colour Pale green Dark green Dark green

Bloom to fruit

maturity

5–9 months 10–16 months 6–9 months

Size Variable (to large) Variable (intermediate) Variable (to

small)

Colour of fruit Green or reddish Green Often dark

Skin thickness Medium Thick Very thin

Skin surface Shiny Rough Waxy bloom

Seed size Variable Small Large

Seed cavity Variable Tight Loose

Oil content Low High Highest

Pulp ﬁ bre Less common Less common Common

Pulp ﬂ avour Sweeter, milder Rich Anise-like, rich

156 Chapter 7

elevations of Mexico (Fig. 7.1). Leaves of the Mexican race are anise-scented

and 60% of the essential oil is the monoterpene estragol (Scora and Bergh,

1992). These races are recognized as subspecies P. americana var. americana

(West Indian), var. drymifolia (Mexican) and var. guatemalenis (Guatemalan)

and are based upon taxonomic, biochemical, isozyme and molecular data

(Bergh and Ellstrand, 1986; Furnier et al., 1990; Ashworth and Clegg, 2003;

Chen et al., 2009). Ben-Ya’acov et al. (1995) have suggested adding a new

race, which they call var. costaricensis. Due to the outbreeding nature of these

taxa and human selection and cultivation, there are many interracial hybrids

and some of the principal commercial cultivars are of hybrid origin.

ECOLOGY

Ecological requirements of avocado should be viewed in terms of the areas

of geographical origin. It is generally considered to be a subtropical plant,

except for the tropical West Indian race. Regardless of origin, the avocado has

shown adaptability to a wide range of ecological conditions, from the tropics

to approximate latitudes of 30° N and S. This wide distribution may be due

to the broad genetic di erences of the three horticultural races. In some high

Andean regions, Mexican avocados grow well under these harsh conditions.

Soil

Avocado is grown in a wide variety of soil types. Deep soils of volcanic origin,

sandy loam soils, calcareous soils and other soil types have supported good

growth. Soil pH may range from 5 to around 7. Since avocado is highly

susceptible to root rots, good drainage is crucial and a high water table

undesirable. Trees show dieback in parts of ﬁ elds when the water table is less

than 1 m.

Avocado has little tolerance for saline conditions. Kadman and Ben-

Ya’acov (1970a) produced various degrees of leaf burn by irrigating an

avocado orchard with water containing 150–170 mg chlorine/l. It has also

been shown that West Indian seedlings are more tolerant to salt than Mexican

seedlings, with Guatemalan having an intermediate tolerance (Table 7.1).

Climate

Rainfall

Most cultivars are sensitive to water stress and to excess moisture caused

by poor drainage. In Hawaii, avocado trees have grown well under annual

rainfall of 3125 mm, largely due to the excellent drainage provided by the

Avocado 157

‘a’ a’ soil (crushed lava rock). Generally, a moderate rainfall range between

1250 mm and 1750 mm per annum with good distribution is desirable.

Almost all avocado-growing areas have wet and dry periods, necessitating

some form of supplemental irrigation.

Avocado inﬂ orescences are not damaged by moderate amounts of rain

for short periods, although relatively dry conditions are preferred during

ﬂ owering. Avocado roots are shallow, and prolonged dry conditions during

the critical periods of ﬂ owering and fruit set can cause ﬂ ower and young-fruit

drop. Among the three races, West Indian cultivars are more adapted to high-

summer rains, while the Mexican races possess greater tolerance to water

stress and lower humidity.

Temperature

Humans have attempted to broaden the range of the three races for economic

reasons by cultivation in areas with seasonally adverse conditions. The West

Indian race is best adapted to a humid, warm climate and monsoon rains, with

optimum temperatures around 25–28°C (Table 7.1). Higher temperatures

depress photosynthesis, thus lowering yields. This race is susceptible to frost

and has a foliage tolerance to a minimum temperature of 1.5°C. Mature trees

of Mexican cultivars have been observed to tolerate temperatures as low as

−4 to −5°C without damage to the foliage and wood, although ﬂ owers are

damaged. The Guatemalan race is adapted to a cool tropical climate but is less

tolerant of low temperatures than the Mexican race (McKellar et al., 1992).

Cultivars have shown tolerance to light frost down to −2°C, but ﬂ owers are

damaged by even light frost (Bower, 1981a).

Night temperatures of 15–20°C and day temperatures of ~20°C are the

most suitable temperatures for ﬂ oral development, pollen-tube growth and

embryo development (Table 7.2). Generally, high humidity, exceeding 50%,

is desirable, especially during ﬂ owering and early fruit set. The Mexican–

Guatemalan hybrids, such as ‘Fuerte’, have shown wider temperature

tolerance to cold than those of the Guatemalan race. Vegetatively, ‘Fuerte’

Table 7.2. Effect of growing temperature (day/night) on vegetative growth and

ﬂ owering of ‘Hass’ avocado (after Chaikiattiyos et al., 1994).

Temperature

Percentage of terminal shoots

(°C)

Panicle Vegetative Dormant

15/10 35 0 65

20/15 20 0 80

25/20 0 100 0

30/25 0 100 0

158 Chapter 7

survives temperatures above −4°C, although the ﬂ owers are damaged and

fruit set can be very poor at 17/12°C (day/night).

Solar radiation and photoperiod

Avocado is a typical C

plant, with maximal CO

exchange occurring at

20–25°C. The light saturation point for photosynthesis of mature ‘Hass’

avocado trees is 1110 mol quanta/m

/s photosynthetic photon ﬂ ux, about

half that at midday in the tropics. Leaves take about 40 days from bud-break

to when they become net exporters of photoassimilates. During these 40 days

leaves may compete with developing fruit for available photoassimilates, and

this competition inﬂ uences fruit retention and fruit development. Day length

is apparently of little importance, as there have not been any published studies

on avocado responding to photoperiod.

Wind

The avocado tree is easily damaged by winds, due to its brittle branches.

Moderately high winds can cause severe damage. If orchards are not located

in naturally sheltered areas, windbreaks are advised.

GENERAL CHARACTERISTICS

Tree

The avocado tree is variable in shape, from tall, upright trees to widely

spreading forms with multiple branches. Trees can attain heights of 15–18 m,

with manageable height being controlled by pruning. Although classiﬁ ed as

an evergreen, some cultivars shed leaves during ﬂ owering, which are replaced

rapidly from terminal shoots. Others shed their leaves gradually, so that

they are never without leaves completely. The dark green leaves are spirally

arranged and variable in size, from 10 to 13 cm wide and from 20 to 25 cm

long, entire, elliptic or ovate to lanceolate (Fig. 7.2).

New growth occurs in ﬂ ushes (Fig. 7.3). Flushes of shoot and root tend to

alternate on a 30–60-day cycle (Ploetz et al., 1991). Root growth continues

throughout the year in subtropical areas, even at a low rate between the

ﬂ ushes, while shoot growth may stop. The period between ﬂ ushes varies

with location (Fig. 7.3) and cultivar. Growth ﬂ ushes in summer tend to be

asynchronous, with only a portion of a tree canopy being involved. Trunk

starch concentration ranged between 4.5 and 6.3% during active tree and

fruit growth. In trees where the fruits are not harvested until full maturity

with 30% dry matter, a trunk starch concentration of 5.3% occurs prior to

ﬂ owering, versus 7.7% in trees harvested earlier (Kaiser and Wolstenholme,

1994).

Avocado 159

(a)

(b)

(c)

3 mm

Fig. 7.2. Avocado leaf, fruit and ﬂ ower. Flower (a) is from the ﬁ rst opening stage

and is female; (b) is the second opening and male, with the anthers semi-erect and

dehisced; and (c) is a fully mature ﬂ ower after dehiscence.

160 Chapter 7

The juvenile period in avocado can be from 5 to 15 years. If girdled in

early autumn 3 years after planting, ﬂ owering and fruit set can be increased

signiﬁ cantly. Since the cultivars ‘Pinkerton’ and ‘Gwen’ have precocious

o spring, juvenility is likely to have a genetic basis, which is modiﬁ ed by

environment (Lavi et al., 1992).

Inﬂ orescence and ﬂ ower

The small, pale green or yellowish-green ﬂ owers are borne on multi-

branched axillary panicles terminating in a shoot bud (Fig. 7.2). One or two

million ﬂ owers may be produced in a single ﬂ owering period, although only

about 200–300 fruit mature (Whiley et al., 1988b). This ﬂ owering leads to

considerable water loss, and the recommendation is to irrigate during this

period. The ﬂ ower is bisexual with nine stamens, six of which form the outer

circle and three in the inner circle. At the base of the inner circle are located a

pair of nectaries, alternating with three staminodes, which also secrete nectar.

Each stamen has four pollen sacs, which release cohesive pollen. The single

pistil contains one carpel and one ovule (Bergh, 1976).

The avocado ﬂ ower has a unique ﬂ owering behaviour (Fig. 7.4), and

all avocado cultivars and seedlings, irrespective of race, fall into one of two

complementary groups, designated ‘A’ and ‘B’ (Table 7.3). Flowers of the

Flower bud

development

Flowering

fruit set

Vegetative

growth

Harvest

Root

growth

Fruit

drop

Fruit

drop

May Jun Jul Aug Sep Oct Nov Dec

Month

Jan

Growth

Feb Mar Apr May Jun

Fig. 7.3. Phenological cycle for bearing cv. ’Fuerte’ in Queensland, Australia,

showing the development and interaction between root, shoot, ﬂ ower and fruit

growth. The cycle will vary with the cultivar and needs to be determined for each

location (redrawn from Whiley et al., 1988a).

Avocado 161

‘A’ class open in the morning for 2–3 h, functioning as females with a white

stigma, while the stamens remain closed and are in a horizontal position.

These ﬂ owers close at approximately noon and reopen the following day

during the afternoon hours for 3–4 h, functioning now as males, with stamens

in a vertical position. The stigmas are no longer functional. Flowers of the ‘B’

class open in the afternoon as females, the stamens remaining closed. These

ﬂ owers close in the evening and reopen the next morning as male ﬂ owers. This

phenomenon is called protogynous, diurnally synchronous dichogamy (Bergh,

1969). The dichogamy is protogynous, as the pistil matures before the stamens

in both classes and all ﬂ owers of a class are synchronized to be functionally

female at one time of the day and functionally male at another time. Looking

at the whole tree with numerous ﬂ owers opening any day during the ﬂ owering

period, varieties of the ‘A’ group are in the female stage during the mornings

and in the male stage during the afternoons and those of the ‘B’ group are

in the female stage in the afternoons and in the male stage in the mornings;

this way they complement each other for fertilization purposes. Temperatures

of 17/12°C and 33/28°C during ﬂ owering time can prevent pollen-tube and

embryo growth, resulting in the production of unfertilized, underdeveloped

fruit. This disruption of fruit set, with endosperm and embryo development

not being observed at low temperatures (17/12°C), is more marked in type

‘B’ ﬂ owers (cv. ‘Fuerte’), where no female ﬂ ower opening occurs (Sedgley and

Grant, 1983). The ﬂ owering cycle is extended by cool temperatures from the

usual 36 and 20 h for types ‘A’ and ‘B’, respectively. Growing temperatures of

25–30°C during the day and night temperatures of 15–20°C are considered

optimum (Table 7.2). A much cooler temperature range during winter will

stimulate ﬂ owering (Whiley, 1984). Type ‘B’ cultivars (‘Fuerte’) are generally

less productive than type ‘A’ (‘Hass’) under cool ﬂ owering conditions.

Time

Type A

Day 1 Day 2

Type B

06:00 12:00 18:00 06:00 12:00 18:00

Fig. 7.4. Protogynous dichogamy pattern of ﬂ ower opening involves two types, A

and B, with both types found in the three ecological races. This behaviour enhances

cross-pollination. These patterns may be disrupted by low temperatures and some

overlap occurs.

162 Chapter 7

Flowering occurs from late autumn to spring, depending upon the cultivar

and prevailing temperatures (Fig. 7.3). West Indian and Mexican cultivars

generally may start to ﬂ ower early, in October or November and October–

December, respectively, north of the equator. The West Indian avocado is

called the summer avocado in Hawaii. Guatemalan cultivars and many

Guatemalan × Mexican hybrids begin to ﬂ ower around March, extending to

May, and are called winter avocado in Hawaii. In the largest ‘Hass’-growing

area in the world, Michoacán, México, the trees can ﬂ ower three or four times

per year; the ﬁ rst, called ‘crazy’ ﬂ owering, occurs in August–September, the

second or ‘advanced’ in October–November; the ‘normal’, which generally is

the heaviest, occurs in December–January and, ﬁ nally, the ‘March’ ﬂ owering,

which takes place at the beginning of spring. These ﬂ owering events may not

occur in all trees, and the intensity of ﬂ owering will vary according to the fruit

set in the other ﬂ owering cycles (Salazar-García, 2000).

Pollination and fruit set

The protogynous, diurnally synchronous dichogamy in avocado ﬂ owers is

the normal behaviour and occurs if warm weather prevails during ﬂ owering.

Synchronous dichogamy of ﬂ owers of the same cultivar restricts self-

pollination and encourages cross-pollination between those of complementary

groups. Exposure to sun, wind and temperature changes can cause variability

in the time of ﬂ oral anthesis, prolonging the open period and time between the

two open periods, and increasing the overlap of female and male opening on a

single tree. However, with moderate day temperatures (25°C) and cool nights

Table 7.3. Classiﬁ cation of selected avocado cultivars according to ﬂ ower types and

climate adaptation.

Type A Type B

Subtropical

Anaheim,Wurtz Bacon, Edranol

Hass, Lamb Hass Fuerte, Ettinger

Gwen, Hazzard Nabal, Millicent

Jalna, Pinkerton Ryan, Sharwil

Reed, Rincon Zutano,Colin V-33

Tropical

Catalina, Collinson Booth 7, Booth 8

Choquette, Fairchild Gripiña No. 2, Hall

Lula, Princesa Itzamna, Kampong

Russell, Semil 34 Linda,

Monroe

Semil 42, Semil 44 Pollock, Prince

Simmonds, Waldin Semil 43, Winslowson

Avocado 163

(20°C), there is su cient overlap of ﬂ ower types to permit self-pollination of

up to 93%. The possibility of self-pollination is enhanced by relatively long

pollen viability. There is also evidence that the stigma remains white and is

still receptive on the second day (Davenport et al., 1994). The avocado can

be insect-pollinated, although self- or wind pollination is possibly the norm

(Davenport et al., 1994). Insects, including honey bees, can carry the sticky

pollen on their bodies and are capable of depositing viable pollen from one

ﬂ ower cycle to another within the same cultivar.

In spite of the fact that some studies have shown relatively high rates of

self-pollination, most investigators have advocated interplanting of pollinator

cultivars of the complementary class in orchards, in order to increase fruit set

(Bower, 1981c). In the case of areas with mild climates, such as Michoacan,

México, there is no need for interplanted pollinator cultivars and most

orchards are made up by solid blocks of ‘Hass’ (Salazar-García, 2000).

Some cultivars are more e ective in increasing fruit set than others.

This may indicate the presence of varying degrees of incompatibility among

cultivars, with some complementary cultivars superior to others. Mexican

cultivars are more e cient pollen providers in California and Israel, while

Guatemalan cultivars are more e ective in Florida, because of greater cold

tolerance of pollen improving the chances in the fertilization process (Gazit,

1976). Under warmer conditions, West Indian hybrids are good as pollen

donors, probably due to their greater tolerance of higher temperatures.

However, fruit set may be a poor measure of ﬁ nal matured fruit, as all cultivars

lose ﬂ owers and developing fruitlets, regardless of pollination.

Following pollination, considerable fruit drop occurs due to poor

pollination and excessive vegetative growth (Wolstenholme and Whiley,

1992). There is probably su cient carbohydrate available from mature leaves

to support the growth of both developing fruitlets and young leaves (Finazzo

et al., 1994). This supply during early fruit development does not limit fruitlet

growth or stimulate fruitlet abscission. However, the lack of an adequate

spring shoot growth, though competitive, will mean that fruit set and early

fruit growth will be dependent upon older leaves and stored carbohydrate,

which may be depleted by ﬂ owering. The later vegetative growth ﬂ ush near

harvest is crucial for ﬁ nal fruit growth, build-up of carbohydrates and the

following period of root growth (Fig. 7.3). This is discussed further with

respect to maturity of fruit at harvest and biennial bearing.

Fruit

The avocado fruit is a one-seeded berry (Fig. 7.2). The single large seed is

composed of two cotyledons enclosing an embryo and is surrounded by a thick

ﬂ eshy mesocarp. The skin varies in thickness up to 6 mm, depending upon the

race (Table 7.1) and has 20,000–30,000 stomata per fruit, less than on a leaf.

164 Chapter 7

The skin colour of the ripe fruit ranges from several shades of green to yellow-

green, from reddish to maroon and from light to dark purple. The buttery ﬂ esh

(mesocarp) is greenish-yellow to bright yellow to cream when ripe. Oil content

ranges from 7.8 to 40.7% on a fresh-weight basis (Kawano et al., 1976). Size

varies from the small fruit of some Mexican types, about 225 g or less, to the

large Guatemalan types, 1.4–2 kg or more (Table 7.1). In shape, the fruit is

usually pyriform to oval and round.

In West Indian and Mexican cultivars, the fruit matures 150–240 days

after anthesis, while Guatemalan cultivars take more than 250 days (Fig. 7.5).

All show a typical sigmoid growth curve (Fig. 7.6). There is little delay before

growth occurs in fruit, seed and pericarp thickness.

CULTIVAR DEVELOPMENT

Cytogenetics and genetics

Persea species generally have a diploid number of 24 chromosomes. Among P.

americana materials examined, Garcia (1975) found one triploid (2n = 36) and

Capac

Mexican

100

200

300

Fruit mass (g)

400

500

600

70 140

Days from full bloom

210 280

Taylor

Guatemalan

Waldin

West Indian

Fig. 7.5. Increase in fruit mass of three cultivars from different ecological races,

showing the difference in time for fruit to reach maturity and ﬁ nal fruit size relative

to the ecological race (redrawn from Valmayor, 1967).

Avocado 165

a tetraploid (2n = 48). Karyotype in Persea is asymmetric, with chromosomes

ranging in size from 2.3 µm to 6.1 µm.

Garcia and Tsunewaki (1977), using peroxidase isozyme analysis, found

signiﬁ cant variations between Mexican strains, within and between nine

states in Mexico. The three races showed signiﬁ cant variation in their pattern

of activities. The frequency of signiﬁ cant variations within strains of the three

races is high in the Guatemalan (62.5%), intermediate in the West Indian

(50.0%) and relatively low in the Mexican race (39.0%). Isozymes have also

been used as genetic markers to detect di erent genotypes resulting from

natural outcrossing and controlled pollinations (Bergh and Ellstrand, 1986).

A number of molecular approaches have been used as genotypic markers and

assignment of racial composition. E orts to apply these techniques in avocado

breeding programmes are hampered by the long generation time and the

inability to perform controlled pollinations (Violi et al., 2009).

Skin colour, ﬂ owering group and anise scent in the leaves are probably

coded by several loci, having several alleles in each loci (Lavi et al., 1993a). The

juvenile period also has a major genetic component. Quantitative traits, such

as tree size, ﬂ owering intensity, fruit weight, fruit density and harvest duration,

show both additive and non-additive genetic variance (Lavi et al., 1991).

125

100

Fruit

length

Seed

length

Pericarp

thickness

0 50 100

Days from full bloom

Fruit, seed and pericarp (mm)

150 200

Fig. 7.6. Rate of total fruit and seed growth and the increase in pericarp thickness of

the West Indian cultivar ‘Waldin’ (redrawn from Valmayor, 1967).

166 Chapter 7

Breeding

Intensive avocado breeding has been conducted over many years in the USA,

Israel, South Africa and other countries. However, until recently, cultivars in

the avocado-growing countries of the world originated as chance seedlings

(Bergh, 1976).

Breeding methods may be by self-pollination or by hybridizing two selected

parental cultivars, the choice depending upon objectives of the breeding

programme. The avocado is highly heterozygous, because of signiﬁ cant cross-

pollination between complementary cultivars, and signiﬁ cant variability

can be obtained among self-pollinated progenies (Lavi et al., 1993b; Violi

et al., 2009). Selﬁ ng can be achieved by the use of cages with pollinator bees

enclosed within the tree or by using isolated trees of a desired parent cultivar

(Bergh, 1976). Outcrossing is reported to be nil where trees of a cultivar

are separated from other genetic lines by 100 m or more. Variations in daily

weather conditions during the ﬂ owering period may disrupt the diurnal

synchrony of the ﬂ owers, allowing self-pollination.

Cross-pollination is necessary when two or more desirable traits are to be

combined or when traits intermediate between two cultivars are desirable, but

this has proved di cult with avocado. The major cultivars in subtropical areas

are hybrids of the Guatemalan and Mexican races, as the Mexican race is the

source of cold-hardiness. In tropical regions, hybrids of the Guatemalan and

West Indian races prevail.

Selection and evaluation

Breeding objectives may be divided into traits that are universally desired

and those which are regionally speciﬁ c. Tree characteristics sought after in

all growing areas are ease in propagation, vigour, precocity, spreading, short

fruit-maturation period, heavy and regular bearing, and wide adaptability

with resistance to disease and insect pests. Traits speciﬁ c to regions are cold

or heat tolerance and salinity tolerance. Other qualities, such as dwarﬁ ng or

semi-dwarﬁ ng, genetic uniformity, freedom from sun-blotch disease, caused by

a viroid, and drought resistance, are also constantly evaluated (Bergh, 1976).

Universal fruit characteristics are resistance to diseases, pests and

blemishes, long tree storage, uniform ripening, minimum ﬁ bres and long shelf-

life (Currier, 1992). Traits that di er due to speciﬁ c climatic conditions or

market preferences are fruit size and shape, skin colour, oil content and chill

tolerance. Market preference is usually based upon consumer familiarity with

certain traits. Fruit size is a good example. Consumers in California generally

prefer a size range of 200–300 g, while in most Latin American countries

larger fruits are preferred.

Avocado 167

Breeding for cold-hardiness is a major objective in the subtropics.

‘Brooksville’, a seedling of the Mexican race, has shown outstanding cold-

hardiness, withstanding artiﬁ cial chilling to −8.5°C. ‘Gainesville’, another

Mexican type, withstands ﬁ eld temperature as low as −9.4°C. The cold-

hardiness of these cultivars has to be combined with genes for dependable

productivity and fruit market acceptance (Knight, 1976).

Avocado rootstock breeding is an important aspect of the total breeding

programme. The avocado root rot, caused by Phytophthora cinnamomi, has

led to testing thousands of seeds and bud-wood from avocado trees that have

resisted the disease over many years and other Persea species collected in their

native habitats. Small-fruited species, such as Persea caerulea (Ruiz y Pavón)

Mez., Persea donnell-smithii Mez., Persea pachypoda Nan and Mart. and Persea

cinerascens Blake, though having strong resistance, are graft-incompatible

with the avocado. Hybridization between the small-fruited Persea species and

avocado has not been successful. California and Florida have been the most

active places doing hybridization, introducing species and varieties from their

native sites and trying existing local or foreign materials in search of better

rootstocks; Israel, South Africa, Australia and lately Chile have also been

working on this important matter.

Rootstocks

In California, several rootstocks have been tried and used, especially for root

rot resistance, with salinity and alkalinity resistance being less important.

After many years of using Mexican seedlings like ‘Topa Topa’ and ‘Lula’, with

the increase of the root rot problem in the 1970s the industry adopted the

rootstock ‘Duke 7’, a Mexican seedling of ‘Duke’ with moderate resistance

to root rot, which became the ﬁ rst commercially successful rootstock that

was propagated vegetatively. Another resistant rootstock, ‘Martín Grande’

(G-775C), a hybrid from P. americana and P. schiedeana, did not perform well

and was discarded. ‘Thomas’, ‘D9’ and ‘Barr Duke’ (all Mexican) have greater

resistance than ‘Duke 7’ and are available (Ben-Ya’acov and Michelson,

1995). The latter three were all found in infected ﬁ elds. In the absence of root

rot, the rootstock can signiﬁ cantly inﬂ uence canopy growth and yield. ‘Duke

7’ and ‘Thomas’ produce signiﬁ cantly more fruit per cubic metre of canopy

than other rootstocks, with ‘D9’ and ‘Martín Grande’ being the poorest

performers (Arpaia et al., 1992). During the last few years ‘Toro Canyon’, of

the Mexican race, has become important; it is more resistant to root rot than

‘Duke 7’ and more tolerant to salts than the Mexican seedling rootstocks; it

also has resistance to Phytophthora citricola. Two releases from the University

of California-Riverside are ‘Zentmyer’ and ‘Uz’ of the Mexican race, which

look very promising. Additionally, California has introduced, and will probably

be using commercially, the ‘Dusa’ and ‘Latas’ (Mexican × Guatemalan)

168 Chapter 7

clonal rootstocks developed in South Africa. ‘Dusa’ has already been released

to nurseries since it is root rot and salinity tolerant. Several dozen selﬁ ng or

outcrossing seedlings showing exceptional resistance to Phytophthora root rot

are under trials.

South Africa has serious root rot problems, and they followed a path

similar to California in the early years of last century and used Mexican

seedling rootstocks. In the 1950s, because most of their Mexican mother

plants were contaminated with sun blotch, they started using the Guatemalan

‘Edranol’, which had no resistance to root ríot, and later ‘Duke’, and then

after many trials ‘Duke 7’, which is now the standard rootstock, providing

reasonably healthy, productive and uniform trees (Kremer-Köhne and Köhne,

2007). Recent rootstock selections from South Africa, ‘Latas’ (Merensky

I), ‘Dusa’ (Merensky II) and ‘Evstro’ (Merensky III) have great production

potential with ‘Hass’ and tolerance to Phytophthora root rot and salinity. ‘Dusa’

is more root rot tolerant and productive than ‘Duke 7’ and it has been made

available to growers in several countries. Australia uses plants grafted on

seedling rootstocks that are very diverse; this complicates management of the

orchard. They have started a programme to identify superior rootstocks and

are looking for an e cient clonal propagation system. They will start selecting

material from superior trees in the ﬁ eld and will evaluate imported rootstocks.

Chilean breeders used plants grafted mainly on ‘Mexicola’, and other Mexican-

race seedlings are going in the same direction. While in Peru ‘Topa Topa’

seedlings are generally used, and West Indian types imported from Israel are

used in areas with salinity.

A rootstock with resistance to salinity is a focus of research in Israel,

California, Chile, Australia and the north and central coasts of Peru. The

three races di er in their ability to resist the uptake of salts (Table 7.1), in

their ability to retain the toxic salts in the root system without translocating

them to the scion and in their tolerance within their tissues. The West

Indian rootstocks have the highest level of tolerance to salinity, followed by

Guatemalan and Mexican races (Ben-Ya’acov and Michelson, 1995). Israel

has taken two approaches: (i) selection of types that produced a resistant

seedling population; and (ii) selection of individual resistant plants for

vegetative propagation. Unfortunately, the true West Indian and high-salinity-

resistant types are di cult to propagate by cuttings. The cold-tolerant Mexican

‘Toro Canyon’ and ‘Duke 7’ have the best salinity rating; ‘Thomas’ and ‘Martín

Grande’ had intermediate ratings; and ‘Barr Duke’ had the lowest rating. The

recent rootstock selections from South Africa, ‘Latas’, ‘Dusa’ and ‘Evstro’,

show some salinity resistance.

The main problem with clonal rootstocks is that the plants lack a tap

root, and therefore special care has to be taken that water supply is timely

and adequate, especially in the most superﬁ cial portion of the soil, during

the ﬁ rst year or so, otherwise the plants will su er and many of them will not

recover properly.

Avocado 169

Cultivars

Cultivars from California, and some from Chile, Australia and Israel, are best

suited for subtropical areas or for higher elevations above 800–1000 m in the

tropics; they normally have a higher oil content, which for many consumers

makes them tastier. The cultivars developed in Florida and the Caribbean

Islands are most suited for the tropics and normally have a lower oil content,

and most of them are green when ripe and are therefore called ‘green skins’

in the international trade. Some California and Florida cultivars have become

international (Table 7.4), providing the basis for avocado development in

many countries. ‘Hass’ a Guatemalan type, is the most widely distributed,

grown and exported cultivar, replacing ‘Fuerte’, a Mexican–Guatemalan

hybrid. One or both have dominated the plantings in Australia, Israel, South

Africa, Mexico, Chile, Peru, the Canary Islands and other areas (Table 7.4).

In California, ‘Hass’ has gradually become the dominant cultivar, largely due

to the relatively poor yields and inconsistent bearing of the type ‘B’ cultivar

‘Fuerte’, whose ﬂ owering is disrupted by low temperatures; ‘Zutano’, ‘Bacon’,

‘Gwen’ and ‘Pinkerton’ are other commercial cultivars. In the last years ‘Lamb

Hass’ and ‘Gem’ and a few others have been developed as alternatives or

complements for ‘Hass’. In Mexico ‘Colin V-33’ was selected from a population

of open-pollinated ‘Fuerte’ seedlings; it is a type ‘B’ with very-good-quality

pulp, green-coloured fruit, superior to ‘Fuerte’; it is considered a dwarf plant

and can be used as a dwarﬁ ng interstock (Barrientos-Priego et al., 2000). In

California, the fruit of most cultivars can be stored on the tree for months after

reaching maturity, depending upon season, so not many cultivars are needed

to market fruit throughout the year. However, this tree storage can lead to

more pronounced biennial bearing.

Florida cultivates a larger number of mostly West Indian and West Indian–

Guatemalan hybrids to extend the market season (Campbell and Malo, 1976).

Cultivars are grouped into early-, mid- and late-season. ‘Pollock’, ‘Waldin’,

‘Simmonds’ and ‘Nadir’ are some early-season types. Some mid-season

Table 7.4. A list of selected cultivars grown in major avocado-growing areas.

California Florida Australia Israel

South

Africa Mexico Spain Chile Peru

Fuerte Pollock Zutano Fuerte Fuerte Fuerte Hass Hass Hass

Hass Simmonds Sharwil Hass Hass Hass Bacon Fuerte Fuerte

Zutano Nadir Bacon Nabal Edranol Bacon Fuerte Negra Nabal

Bacon Booth 8 Fuerte Ettinger Ryan Reed Reed la Cruz

Reed Lula Hass Horshim Criollo Zutano Bacon

Pinkerton Hardee Wurtz (Local) Gwen Edranol

Gwen Ruehle

Choquette

Zutano

170 Chapter 7

cultivars are ‘Booth 7’, ‘Booth 8’, ‘Collinson’, ‘Hall’ and ‘Hickson’, while late-

season cultivars are ‘Lula’, ‘Monroe’, ‘Choquette’, ‘Booth 3’ and a few others

(Table 7.4). A similar situation occurs in Hawaii, where a large number of

cultivars are grown, including introductions from California, Florida, Australia

and Mexico and selections of local origin. ‘Sharwil’, an Australian cultivar, has

become a leading cultivar, with a recent release, ‘Green Gold’, increasing in

acreage. Puerto Rico and the Dominican Republic cultivate some of the Florida

cultivars along with some locally developed cultivars, such as the West Indian-

Guatemalan hybrids ‘Semil’ and ‘Gripiña’.

Mexico grows ‘Fuerte’ and ‘‘Hass’ as the main cultivars, along with other

California and Florida ones. The ‘Criollo’ is mentioned as a selection of the

Mexican race and is well adapted to median ecological areas of Mexico (Diaz-

Avelar, 1979). Besides Mexico, Brazil has developed a substantial industry,

mostly with introduced cultivars, such as ‘Fuerte’, ‘Hass’, ‘Carlsbad’, ‘Corona’,

‘Edranol’, ‘Nabal’ and ‘Ryan’, and cultivars of local origin, such as ‘Solano’,

‘Ouro Verde’, ‘Quintal’ and ‘Fortuna’.

In Australia, ‘Hass’ and ‘Fuerte’ have been planted most frequently,

especially along the coastal areas of northern New South Wales and southern

Queensland. ‘Sharwil’, a local selection (Guatemalan–Mexican hybrid), has

gained considerable popularity, although in some areas it had ﬂ uctuating

yields. Under tropical conditions in the Northern Territory, the Mexican

and Guatemalan cultivars yield poorly (Sedgley et al., 1985). South African

production is largely from ‘Hass’ and other California cultivars. Israel’s

production was initially based on California cultivars, until an intensive

selection programme over the years produced a large number of local

cultivars, such as ‘Ettinger’ and ‘Horshim’.

In Asia, the avocado has not attained the popularity it has in other areas,

although it was introduced into Malaysia over 120 years ago. In Indonesia,

avocado grows well at 200–1000 m on well-drained soils, and trees are

generally propagated by seeds. In the Philippines, many cultivars have been

introduced from the USA since 1903, and avocado is grown in nearly all parts

of the country, although it has not attained the popularity of other fruit.

CULTURAL PRACTICES

Propagation and nursery management

Avocado is primarily propagated commercially by budding or grafting upon

seedling rootstocks. However, the variability of seedling populations with

respect to certain desirable characteristics, such as resistance to Phytophthora

root rot and tolerance to salinity and calcareous soils, has posed problems

(Ben-Ya’acov and Michelson, 1995). Seedling production has largely changed

Avocado 171

from grafting nursery-grown trees to grafting container-grown trees. Seeds

are taken from fruit picked from trees free of sun-blotch and are treated in

a water bath at 49–50°C for 30 min, cooled and surface-dried in a partially

shaded area. Seeds are planted (broad side down) in polyethylene bags, with a

well-draining potting mix. Seeds germinate in about a month. The papery seed

coats should be removed. If seeds are not very fresh, cutting o a piece of seed

tip or doing some vertical cuts at the side of the seed will improve germination

speed and percentage; sometimes a slice of bottom can also be cut o .

Seedlings may be cleft or side-wedge grafted 2–4 weeks after germination.

Scion wood from terminal growth of sun-blotch-free cultivars should be used.

Propagation is usually done in shade houses, preferably with temperature

control if the environment has a wide temperature range. Grafted plants

must be hardened for approximately 2 weeks under full sunlight before ﬁ eld

transplanting. Under open-ﬁ eld conditions in the central coast of Peru, with

13–15°C lowest temperatures in winter, Duarte et al. (1975) reduced by 2

months the time to obtain a grafted plant with seeds sown at the start of

autumn and by 1 month with seeds sown at the end of autumn, by spraying

the seedlings three times with 250 or 500 ppm GA at 2-week intervals,

starting when they had reached 15 cm.

Leafy avocado cuttings of some genotypes under mist consistently rooted

nearly 100% under practically any conditions, while others did not root at

all or rooted with di culty (Kadman and Ben-Ya’acov, 1970b). Generally,

West Indian cultivars with strong resistance to salinity are di cult to root.

Cuttings from mature trees were di cult to root and, in those that rooted

well, they took 4–10 months to root. Cuttings from 1-year-old seedlings show

a higher percentage of rooting in 4–12 weeks. A 50% light intensity in the

intermittent-mist system during the summer is better for rooting than full

sunlight. The anatomy of the avocado stem provides a reason for the di culty

in rooting as the ﬁ bre bundles and the sclereid ring are thicker in the West

Indian types, intermediate for Guatemalan and hybrid types, and least for the

Mexican cultivars.

Air layers and cuttings have been successfully rooted. Variability exists

in ease of rooting air layers between races and even among cultivars of a

race, and the di culty of large-scale production has discouraged commercial

development. Generally, Mexican cultivars root most easily, followed by

Guatemalan and West Indian, whether by air layering or by cuttings. Time

required for rooting of air layers ranged from 146 to 518 days, depending

upon cultivar and the time of the year. Etiolated stems show few or no sclereid

connections between ﬁ bre bundles, suggesting that the sclerenchyma ring may

be acting as a barrier to root emergence (Gomez et al., 1973). Hence, shoots of

most avocado cultivars produced in light do not root nearly as well as shoots

produced in darkness.

Seedlings produced upon scions of the desirable rootstock cultivar are

grafted by tip grafting as close to the base as possible. Shoots of the scion

172 Chapter 7

are allowed to grow and then cut back to near the base. When new buds

show signs of growth, the entire plant is placed in a dark room, with the

temperatures maintained at 21–23°C. When the new shoots reach about

8–10 cm in the dark, the plants are again placed in light, with a tar-paper

collar placed around each etiolated stem and ﬁ lled with vermiculite to

continue exclusion of light from the base of the shoots. Only the tips of the

shoots are exposed to light, in order to produce green leaves. This procedure

is done under shade to prevent sunburn. Shoots are then allowed to grow

until several leaves have matured. The collar is then removed and shoots are

detached for rooting in propagation frames. Rooting hormones have shown no

beneﬁ cial e ects, although some reports from Australia indicate that a 360

scrape of the etiolated shoot prior to the application of the potassium salt

of indole butyric acid consistently gave a crown of roots. Rooted shoots are

transplanted into 10 cm peat pots and grown in an enclosed area for further

root and top growth and gradually hardened. These rooted plants are then

transplanted into larger polyethylene bags for more growth and hardening,

then grafted when they attain appropriate size. The side-wedge technique is

usually used, so some terminal foliage on the rootstock is retained until scion

growth begins.

In California, South Africa and to a lesser degree in Spain and Chile, clonal

rootstocks are used and propagated based on the double-grafting–etiolation

method. A large avocado seed such as ‘Lula’ is grown in a container to serve

as a nurse stock. When the nurse seedling that was sown into a planting sleeve

is large enough for grafting, a splice or cleft graft with a tolerant rootstock is

made. A metal girdle is loosely put above the bud or graft union so that it will

eventually girdle the stem; the grafted rootstock is forced to root above the

girdle (Brokaw, 1975). The nurse seed with the grafted tolerant rootstock is

then grown in the dark till the graft is 20–40 cm tall. The container is then

removed from the dark, and sterile rooting medium is supplied to cover the

base of the bud union. Adventitious roots develop from the tolerant rootstock.

Once the rootstock growth hardens o , it is grafted with the desirable scion

variety and grown for 2–3 months. The double-grafted plant is then grown

for several months before planting. Rooting hormone or minor cuts near the

bud union between the tolerant rootstock and the nurse seed can enhance

the rooting success of the rootstock. Once in the ﬁ eld it is assumed that the

rootstock will extend its roots and the nurse seed will be excluded from the

system due to the girdle. In South Africa, an improvement to this method

was developed (de Villiers and Ernst, 2007). This consists of positioning

a 55 ml micro-container on the etiolated shoots coming from the grafted

rootstock. Roots will form in these containers, and after grafting the desired

cultivar on to these shoots, they will be separated from the nurse seedling just

above the nurse graft and taken to the nursery for hardening; after this they

will be transplanted into nursery containers or bags. The advantages of this

improvement are that more than one plant can be obtained from a nurse seed;

Avocado 173

reduced plant cost because of the e ciency of this technique; the root system

of the rootstock is separated from that of the seedling, which assures better

sanitary conditions, and it can be inspected at transplant time; plants with a

better root system and with a more uniform growth in the ﬁ eld are obtained.

Field preparation

Land preparation for avocado does not di er from that for other tree crops.

Development of a drainage system is a prime consideration. Subsoiling or

ripping down to at least 0.5 m or more, preferably running diagonally across

the slope to allow subsurface movement of water, aids drainage. If soil pH

needs adjusting, this could be done during the ﬁ nal stages of land preparation.

Cover crops, such as legumes or grain, can be preplanted a year before orchard

planting to increase organic matter and minimize erosion and root rot.

Transplanting and plant spacing

The use of grafted, container-grown trees has dramatically minimized

transplanting mortality. Polyethylene bags can be removed with all the

soil intact around the roots. Soil in the planting hole should be moist but

not wet. In dry areas, application of water in the holes a few days before

transplanting is advisable to moisten the soil. In the tropics, transplanting

can be done during the dry season, if irrigation is readily available; otherwise,

transplanting should be done at the beginning of the rainy season. In the cool

subtropics, where low winter temperatures can be expected, young plants

may need to be protected or transplanting delayed until the coldest period has

passed. In Peru, some growers prefer to plant the rootstocks in the ﬁ eld and

later graft or bud on to them; this results in a more vigorous growth of the

plant during the initial years.

The cultivar’s natural growth habit (spreading or erect), vigour of the

rootstock, and the environment and soils are major determinants of the

mature tree size, and this inﬂ uences spacing and the continued productivity

of the orchard. Close spacing is sometimes used, with later thinning to obtain

maximum beneﬁ ts per unit area. Initial close spacing can be justiﬁ ed only for

precocious cultivars and is beneﬁ cial only if trees are judiciously thinned when

this becomes necessary. For non-precocious cultivars, the yields obtained

before tree thinning becomes necessary may not justify the additional cost.

Traditional spacings in Florida are 7.5–10.5 m in rows and 7.5–12 m between

rows, which precludes canopy overlap. Narrower spacings of 4.5–6 m in rows

and 6–7.5 m between rows lead to higher yields while the trees are young.

In South Africa, similar narrow spacing of 7.5 m × 7.5 m (177 trees/ha) is

recommended for ‘Fuerte’ and 7 m × 7 m (204 trees/ha) for ‘Hass’, requiring

174 Chapter 7

later tree thinning or topping. At close spacing on the square, thinning is done

by removing the trees in every second diagonal row (Bower, 1981b). In Peru,

distances of 6 m × 4 m and 6 m × 3 m are being used, while in Chile 6 m ×

2 m, 6 m × 3 m and even 3 m × 3 m are being tried. The narrow plant spacing

needs careful formation and maintenance pruning to avoid overcrowding.

Intermediate plants will have to be removed as the canopy starts to overlap.

High-density schemes allow for higher initial yields, but management,

especially pruning, has to be more precise.

Placement of pollinizer trees in the orchard so that an adequate ratio

can be maintained after thinning may need to be considered in some spacing

schemes. The old guideline was one pollinizer for every nine trees. Large

blocks of a single cultivar have shown good production, presumably by self-

pollination, but interplanting pollinizer cultivars undoubtedly increases fruit

set for some cultivars that may not have pollen or are a poor pollen source.

‘Ettinger’ is an excellent pollen source for ‘Hass’ and there is a higher survival

of fruit to maturity.

Irrigation

The avocado can tolerate neither water stress nor excess moisture, especially

when drainage is inadequate. Water stress reduces yields, fruit size and

tree vigour. The soil around the trees should be moist but not wet. Irrigation

frequency depends upon ﬁ eld condition, soil drainage and tree density, as well

as canopy size and prevailing weather conditions and past irrigation records.

Evapotranspiration data and tensiometer readings averaged over a period of

days provide a more accurate means of determining irrigation timing. The

application rate is calculated, taking into account the evapotranspiration

rate since the last irrigation, rainfall, percentage canopy coverage of the

ground and e ciency of water use. Young, non-bearing trees require light,

more frequent irrigation. Older trees can withstand longer intervals between

irrigations but never to a point of water stress. Only 50% of the tree’s

requirements should be given in the middle of the cool season and spring,

in order to favour ﬂ owering rather than vegetative growth. When fruit set is

completed, irrigation reverts to normal amounts during fruit development.

High irrigation rates are necessary during ﬂ owering and may be necessary as

the fruits approach maturity and if the weather is hot and dry (Fig. 7.3). Care

has to be taken not to let the soil dry too much at the time of ﬂ owering and

fruit set, since a marked increase of water in the soil can produce a signiﬁ cant

drop of small fruit. Irrigation is necessary down to at least 60 cm. Total

water applied per year is estimated at about 35–50 ha-cm for mature trees

(Gustafson, 1976).

On level land, less-e cient furrow irrigation or sprinklers can be used,

with micro-irrigation systems (drip or micro-sprinklers) being more e cient in

Avocado 175

water use. Mature trees require eight or more drip emitters around the tree,

providing greater control and higher e ciency of water use (up to 80%). Later

plantings of avocado in California are on the sides of steep hills, which can be

irrigated only by drip irrigation or mini-sprinklers, as in Chile.

Pruning

The growing tips should be pinched o young trees, allowing the development

of a more compact tree. This pinching is continued until the tree is too tall.

Lower limbs are removed only if they interfere with irrigation and fertilization.

Management should be keyed to avoiding vegetative and reproductive growth

occurring at the same time. Since avocado is polyaxial, it must continue

to increase in size to remain productive. Shoot growth in the warm season

occurs in spurts of up to 1 m, which is needed in order to put on leaves

required for fruit growth (Fig. 7.3). Tree trimming aims at a canopy that has

fruit at all heights and reduces the competition for light. Pruning at the bud

ring (several closely spaced buds without subtending leaves), formed at the

conclusion of a shoot growth ﬂ ush, releases more buds and increases shoot

complexity, and hence bearing sites. Cutting below this ring depresses tree

vigour and releases only one bud (Cutting et al., 1994). Bud-ring pruning can

extend the period before trimming is necessary. Pruning should be timed to

the end of the autumn period. Tree growth can also be reduced by spraying

with paclobutrazol, an inhibitor of gibberellin synthesis, though its use is not

approved in some countries. Tree thinning is recommended in South Africa

when 90% of the orchard ﬂ oor is shaded. Topping (stag-horning) is also

practised on healthy trees to rejuvenate a crowded orchard, where the trees

are cut back to 1–3 m from the ground. Tree thinning, topping or stumping is

essential to avoid canopy crowding and the loss of bearing volume in the lower

third or more of the tree. Severe topping to ~3 m means the loss of production

for 2–3 years, while less severe topping to ~5 m can increase fruit yield and the

amount of fruit set in the lower half of the tree (Crane et al., 1992). Cultivars

with upright vigorous growth habits may be severely a ected by topping and

orchards may have to be rejuvenated in sections over several years, by topping

to 5 m. For very high density, the plants should be cylindrically shaped, while

for not so high densities a pyramidal shape is more appropriate.

Fertilization

Fertilizer practices di er in avocado-producing areas, due to di erences in

climate, soil, cultivars and management practices. Numerous attempts have

been made to determine critical foliar nutrient levels, in order to regulate

the application of macro- and microelements. The following ranges of foliar

176 Chapter 7

levels for macronutrients are established: nitrogen (N) 1.6–2.0%; phosphorus

(P) 0.07–0.20%; potassium (K) 0.75–2.0%; calcium (Ca) 1.0–3.0%; and

magnesium (Mg) 0.25–0.50% (Malo, 1976). The ranges for micronutrients

are: iron (Fe) 50–200 ppm; zinc (Zn) 50–150 ppm; and manganese (Mn)

30–70 ppm.

Critical levels have been di cult to establish, due to the highly variable

yields of avocado. Nitrogen seems to be one of the controlling factors in

avocado yields, as this is the only element that has shown a curvilinear

relationship to yields. Maximum production of ‘Fuerte’ is found at a moderate

level of N in the leaves, with reduced yields occurring at levels below and above

the moderate level. In ‘Fuerte’, a range from 1.6 to 2.0% N in the leaves in late

summer is a desirable level in order to maintain high production. Nitrogen

fertilization is not recommended during the cool season, with application

delayed to the summer leaf and root ﬂ ush (Fig. 7.3). This application should

include P and K. A later application of P and K should also occur near the

peak of fruit set (Whiley et al., 1988a).

As for many tree crops, including avocado, a soil pH of 7.0 and above

creates problems with Fe and Zn deﬁ ciencies, refered to as lime-induced

chlorosis. Iron chelate is used to correct Fe deﬁ ciencies. Soil application of

Zn is more e ective in acid soils than in alkaline soils, and foliar application

has not proved successful. In Florida, where deﬁ ciencies of Fe, Zn and Mn

are common, good results are obtained by combining the chelates of these

elements and applying them through the drip-irrigation system. Boron (B)

deﬁ ciency occurs in some soil types, and ‘Sharwil’ appears to be more sensitive

to B deﬁ ciency.

Pest management

Diseases

A number of avocado diseases have been reported from producing areas

around the world (Table 7.5), the most serious being root rot caused by P.

cinnamomi Rands. This is suspected when trees show a gradual decline, with

leaves becoming smaller, yellow-green in colour and shedding. In severe

cases, twig dieback occurs. The destruction of the unsuberized feeder roots is

associated with high soil moisture in poorly drained areas of the ﬁ eld, with P.

cinnamomi thriving under wet soil conditions, especially when the temperature

ranges from 21 to 30°C and with a soil pH of 6.5 (Zentmyer, 1976). Soil

fumigants, fungicides and sanitation have been used, with a research

emphasis on the development of resistant rootstocks, such as ‘Martín Grande’,

‘Thomas’, ‘Barr-Duke’ and ‘D9’ (Gabor et al., 1990). The use of resistant

rootstocks is integrated with hygiene, sanitation and cultural methods (Co ey,

1987). Trunk-injected phosphonate fungicide (Aliette-Fosetyl-Al) is timed to

coincide with the shoot maturation (Fig. 7.3), the phosphonate being carried

Avocado 177

to the mature shoots and then translocated to the roots, peaking in the root

in about 30 days (Whiley et al., 1995). In California, the root-ball of replant

trees should be drenched with a solution of phosphonate at the time of

planting, followed by two to three foliar sprays with the same chemical. This

chemical can also be sprayed on to the foliage of diseased trees as long as

functional leaves are present. If too few functional leaves remain on the tree,

heavy pruning is performed to induce new shoots and leaves before spraying

phosphonate. Phosphonate applications are repeated three or four times a

year. However, the chemical does not eliminate the fungus from the soil and

must be used with management practices.

In Mexico, Phytophthora root rot control is based upon integrated crop

management (ICM). The ICM approach is based upon improving plant vigour,

restoring the equilibrium between the root and foliar systems, increasing the

soil ﬂ ora beneﬁ cial to the avocado and harmful to disease organisms, improved

irrigation and fertilization, reduced fungal and insect attacks and avoiding

management practices that weaken the tree and favour the disease attack.

Table 7.5. Some important diseases of avocado.

Common name Organism

Parts affected,

symptoms

Region or

country

Root rot

Phytophthora

cinnamomi

Feeder roots, tree

decline

Worldwide

Verticillium wilt Verticillium dahlia

(Verticillium albo

atrum)

Wilting of branches,

death of trees

California,

Australia,

Florida

Armillaria root rot

and crown rot

Armillaria mellea

Large roots, gradual

death of trees

California,

Mexico

Sun blotch Sun-blotch viroid Stunted, decumbent

growth, distorted

leaves, yellow or red

streaks on fruit

Many areas

Anthracnose

Colletotrichum

gloeosporioides

Leaves, most serious

on fruit, especially

after harvest

Worldwide

Stem-end rot

Dothiorella aromatica

(Dothiorella gregaria)

Diplodia natalensis

Purplish-brown spots

on fruit surface,

ﬂ esh discoloration,

offensive odour

USA, South

Africa, Israel,

Australia,

parts of South

America,

Caribbean

Cercospora spot Cercospora purpurea

Leaves, young stems,

fruit

Florida, other

areas

Scab

Sphaceloma perseae

Foliage, fruit Humid tropics

and subtropics

178 Chapter 7

The main measures consist of: (i) periodic incorporation of cattle manure

to a depth of 30 cm to keep the organic matter content of the soil around

3–3.5%, checking this periodically; (ii) chemical fertilization through soil and

foliage to keep adequate foliar levels of elements; (iii) rejuvenation pruning of

a ected trees with more than 70% defoliation to restore root/foliage ratios;

(iv) proper irrigation to avoid plant stress, by not allowing soil moisture to

drop below 70% of ﬁ eld capacity; and (v) adequate sanitary controls to reduce

damage by other enemies (Mora et al., 2000). This approach has provided

results comparable to or better than the use of chemicals. Chemicals are still

recommended when tree decline is serious. In Australia, root rot has been

minimized by building up heavy mulch with bagasse, grass or cereal straw.

This reinforces the importance of using organic matter to create a better

environment for plant-friendly organisms and fungus antagonists.

Many of the diseases reported are not necessarily serious, although the

potential for causing heavy losses exists. Avocado scab is considered to be an

important disease of avocado fruit and foliage in Florida (McMillan, 1976).

Among fruit diseases, anthracnose, stem-end rot and avocado scab can cause

serious problems. Anthracnose requires control practices in the ﬁ eld during

fruit development.

Sun blotch, caused by a viroid, is of concern. Trees are stunted, with

cracked bark, necrotic streaks on branches, and white or light green areas on

the fruit. There are no known vectors, and what makes it a potentially serious

problem is the presence of many symptomless carrier trees. The disease is

transmitted by use of seedling rootstocks from such trees, as well as grafting

with scion wood from infected plants. Scion wood from a healthy tree grafted

upon a ‘carrier’ rootstock becomes infected. In the major avocado-growing

countries, indexing techniques have been developed and used to identify

healthy cultivars for scion wood, as well as those needed for rootstocks

(Broadley, 1991).

INSECTS

There are many insect pests reported in avocado orchards, although they do

not usually pose any serious problems (Table 7.6). Occasionally, a sudden

increase of a speciﬁ c insect can cause severe damage. This increase in an

insect pest is often associated with a sudden change in weather conditions.

Avocado red mite can cause signiﬁ cant leaf damage and a reduction in

photosynthesis and transpiration (Fig. 7.7), possibly leading to a reduction in

yield. Insects such as scales, aphids, mealy bugs and various mite species are

also commonly found in orchards, but natural enemies have been shown to

provide satisfactory control.

In some producing areas, fruit ﬂ ies may require some form of disin-

festation procedure for fruit to be exported to some markets. Studies in

Hawaii with ‘Sharwil’ avocado have shown that it is not normally a host to

the Mediterranean fruit ﬂ y (C. capitata), melon ﬂ y (Dacus cucurbitae) and the

Avocado 179

Oriental fruit ﬂ y (D. dorsalis) at the mature green harvest stage. Under dry

conditions, eggs are deposited between the pedicel and the fruit, making

it a host.

Weed control

Young avocado trees are sensitive to herbicides, so weeding around the trees is

usually done manually. Black polyethylene mulch around the plant is e ective

Table 7.6. Some important insect pests of avocado.

Common name Organism

Parts affected,

symptoms Region or country

Mediterranean fruit

ﬂ y

Ceratitis capitata

Fruit Hawaii

Oriental fruit ﬂ y

Dacus dorsalis

Fruit Hawaii

Queensland fruit ﬂ y

Bactrocera tryoni

Fruit Australia

Black coffee twig

borer

Xylosandrus

compactus

Branches, twigs Hawaii

Chinese rose beetle

Adoretus sinicus

Leaves of young

plants

Hawaii

Fuller rose beetle

Pantomorus godmani

Leaves of young

plants

Hawaii

Spotting bug

Amblypelta nitida

Young fruits Australia

Pine-tree thrips

(greenhouse thrips)

Heliothrips

haemorrhoidalis

Fruit scarring California,

Florida,

South Africa,

Hawaii, Canary

Islands (wide

distribution)

Red-banded thrips

Selenothrips

rubrocinctus

Leaves, fruit

scarring

Wide distribution

Fruit and twig borer

Stenoma catenifer

Perforates fruit,

seed, shoot

terminals

Tropics

Seed and fruit borer

Heilipus laurii

Seed and fruit Tropics

Seed borer

Conotrachelus

perseae

Seed and fruit Mexico

Stem borer

Xyleborus spp.

Stems and

branches

Tropics

Red spider mite

Oligonychus yothersi

Leaves, fruit

scarring

Mainly Chile

Scales

Oligonychus perseae

Leaf scarring Mexico

Saissetia and others

Sap suckers Wide distribution

180 Chapter 7

in preventing annual broadleaved weeds but not e ective against perennial

grasses and nut-sedges (Nishimoto and Yee, 1980). In bearing orchards, the

canopy provides enough shade to prevent weed growth. Inter-rows up to

the periphery of the trees may be mowed or controlled with herbicides. Disc

harrowing of avocado orchards is discouraged, as the shallow feeder roots will

be damaged.

HARVESTING AND POSTHARVEST HANDLING

Harvesting and handling

The stage of fruit maturity when harvested can signiﬁ cantly inﬂ uence the

occurrence of biennial bearing in some avocado (Whiley et al., 1992). In

the tropics, later harvesting of ‘Fuerte’ fruit having 30% dry matter results

in pronounced biennial cropping. Results for a cool subtropical location in

South Africa suggest no e ect of later harvesting on subsequent yield (Kaiser

and Wolstenholme, 1994). Some cultivars can be stored on the tree and

harvested according to marketing schedules. The length of time fruit can be

Fig. 7.7. Inﬂ uence of avocado red mites (Oligonychus yothersi McGregor) on leaf

transpiration, photosynthesis and damage (redrawn from Schaffer et al., 1986).

Avocado 181

left on the tree depends on the cultivar and season. However, this ‘on-tree

storage’ can lead to biennial bearing or crop failure in the following year.

Generally, cultivars of the West Indian race have little or no tree-storage time,

and hybrids, particularly Guatemalan × Mexican, have a longer tree-storage

life. Other tree-storage limitations are fruit drop and development of an o -

ﬂ avour or rancidity with over-maturity. A higher yield can also be obtained if

harvesting is staggered, with 50% of fruit harvested with 21% dry matter and

the remainder at 30%.

A major problem is the stage of maturity for harvest, especially for

cultivars that remain green upon ripening. Some avocados will start changing

skin colour and then fall from the tree when mature, and a few lines can begin

ripening on the tree. Other green-coloured avocados develop a yellowish tint

on the stem near the fruit. Maturity of cultivars that normally change skin

colour from green to reddish or purplish, such as ‘Hass’, is easy to ascertain.

Immature fruit, if harvested, take longer to soften and they shrivel upon

storage, with the ﬂ esh becoming ‘rubbery’ rather than buttery. Most countries

with commercial avocado production have developed some sort of standards

for determining maturity. The increase in oil content is correlated signiﬁ cantly

with maturity. As the fruit advances towards maturity, oil content increases,

the level depending upon the cultivar (Barmore, 1976). In California, oil

content was used as a standard of maturity, with a minimum of 8% oil, based

on fresh mass of fruit, exclusive of skin and seed. Oil content as a measure

of maturity was impractical in Florida, due to wide variations in oil content

among and within cultivars. Some cultivars, particularly those belonging to

the West Indian race, never reach the 8% oil content, as in California. Florida

uses minimum fruit weight and diameter as related to number of days from

fruit set, thus establishing the earliest harvest date for each cultivar (Hatton

and Campbell, 1959). Fruits originating from known bloom dates become

progressively smaller in size from the earliest bloom date to the latest (Hatton

and Reeder, 1972).

Moisture content is also used as a measure of maturity, as it does not

involve oil determination, and there is a negative correlation between oil and

moisture content. As oil content increases during maturation, there is a similar

decrease in moisture content. A 10 g sample of ﬂ esh from a total of ten fruits is

collectively grated and spread on an open dish and dried in a microwave oven

for a few minutes. The minimum dry matter percentage for di erent cultivars

ranges from 17 to 25%. For example, for ‘Fuerte’ the minimum dry matter

percentage is 19%, ‘Hass’ 20.8%, and ‘Zutano’ 18.7%. In more mature fruit

the dry matter can reach 30%. After the minimum moisture content has been

met, fruit comparable to the sample fruit can be picked and ripened at room

temperature. If the sample fruits ripen within 8–10 days without shrivelling,

they are considered to be mature, and the grower can proceed to harvest

comparable-sized fruit on the tree. Grade standards frequently set a minimum

dry-matter percentage of around 20% for ‘Fuerte’, 22% for ‘Hass’, 25% for

182 Chapter 7

‘Gwen’ and 19% for ‘Zutano’ (Rainey et al., 1992). This method is rapid and

less time-consuming and does not involve oil determination.

Fruits are harvested by cutting or snapping o the stem at the base of

the fruit, with about 12 mm of the stem attached. Aluminium picking poles

are usually equipped with a cutter and a bag to catch the fruit. Large trees

on suitable terrain can be partially mechanized by the use of a three- or four-

wheeled, self-propelled, hydraulically powered platform, from which pickers

can use short poles. Pallets or bins should be placed under the shade of trees

while waiting to be picked up for transport to the packing plant. This prevents

overheating of fruit, as precooling is not generally practised.

Postharvest treatments

Most packing houses are automated, with all debris removed automatically

and fruit cleaned with roller brushes. Cleaned fruits pass through graders,

where all diseased, injured and defective fruits are removed and fruits are

separated into size lots for packing. Sizing is done by use of drop-roll (diameter)

sizers or by weight sizers. Each producing country has its own grading

standards and size classes. The major quality criteria are size; skin colour;

freedom from wounds, blemishes, insect damage and spray residues, and

absence of disease, physiological disorders and bruising. Standards for Europe

allow for three classes of avocado, based on appearance, defects, tolerances,

uniformity, packaging and marketing. The minimum mass is 125 g and a

range of size from 125 to 1220 g in 14 ranges is used in all classes (Anon.,

1995). Fruits with lower quality go to processing or are used for local sales.

Sizes of packing cartons di er in various countries. They are usually

corrugated paperboard cartons for single- or double-layer packing, ventilated

for good air circulation. Pads or styrofoam trays with cup impressions may

be used to prevent bruising. Prepacked consumer units in ‘clam shells’

(polyethylene containers) and mesh bags are also used. Fruit may be waxed or

wrapped and packed by hand. All fruit in a speciﬁ c size container must weigh

between a speciﬁ ed minimum and maximum range. Cartons are labelled

with fruit number and size range. In California, packed cartons are cooled at

5–15°C, depending on cultivar, before loading into transport vehicles. ‘Hass’

can be stored at 5°C for 3–4 weeks. Longer storage leads to greyish-brown

internal ﬂ esh discoloration and irregular blackening of the skin.

Storage temperature for delaying ripening varies with the cultivar

temperatures of 12.5, 8 and 5°C are used for West Indian, Guatemalan

and Mexican cultivars, respectively. A relative humidity of 80–90% is

recommended. Other storage methods, such as controlled atmosphere (CA)

and hypobaric (low-pressure) storage, have been evaluated. With CA storage

at 2–5% oxygen (O

) and up to 10% carbon dioxide (CO

) at 5°C and 98–100%

Avocado 183

relative humidity is occasionally used to delay softening and reduce respiration

and ethylene production.

Fruit can be ripened at 25°C or by exposure to 10–100 ppm ethylene at

17–20°C for 12–72 h, depending upon fruit maturity, and then transported

to markets. Following ethylene treatment fruit will ripen in 3–6 days. The

ethylene-treated fruits are marketed locally, as the current market strategy is

to provide ripe fruit for immediate consumption.

UTILIZATION

The avocado is considered a nutrient-dense food (Rainey et al., 1994). It has

the highest ﬁ bre content of any fruit and is a source of food antioxidants

(Bergh, 1990a). Avocado has a high oil content, although Florida cultivars are

lower in oil content compared with cultivars from California. Major fatty acids

are the mono-unsaturated oleic acid, followed by palmitic and linoleic acids.

Palmitoleic acid is found to approximate percentages of linoleic acid, and

values are slightly higher or lower depending upon the cultivar analysed. The

nutrient values of the di erent ecological races also vary, but, in general, it is

a fair to good source of P, provitamin A, riboﬂ avin and niacin (Table 7.7). The

protein content of 1–2% is considered to be greater than in any other fresh

fruit (Bergh, 1990b). Avocado also increases the diet’s content of antioxidants,

foliates, K and ﬁ bre (Rainey et al., 1994).

Avocado is mainly used fresh in salads, its high fat content combining well

with acid fruit and vegetables, such as pineapple, citrus and tomatoes, or with

acid dressings. A major commercial avocado product is guacamole, used as a

favourite dip with potato chips, tortilla chips and similar products. Avocado

may be used to supply the fat content of frozen desserts, such as ice cream

and sorbets. Miller et al. (1965) provide numerous recipes for various types of

salads, cocktails and desserts. In some places, avocado is eaten as a dessert,

adding sugar to it instead of salt. Shakes and ice creams are also made of the

pulp. Recently there is a growing industry of producing avocado oil, which is a

very healthy product, using subtropical varieties.

Deterioration of ﬂ avour and enzymatic discoloration are serious problems

in the commercial processing of avocado (Ahmed and Barmore, 1980).

Avocado is not conducive to heat processing as it results in an o -ﬂ avour.

High polyphenoloxidase and total phenol contents contribute to the processed

product’s browning potential, with di erences in browning potential occurring

among cultivars. Enzymatic browning of avocado products can be minimized

by processing a cultivar with low polyphenolase activity into an acidiﬁ ed

product containing an antioxidant (e.g. ascorbic acid), packing under N or a

vacuum and storing at low temperatures.

184 Chapter 7

FURTHER READING

Ben-Ya’acov, A. and Michelson, E. (1995) Avocado rootstocks. Horticultural Reviews 17,

381–429.

Bower, J.P. and Cutting, J.C. (1988) Avocado fruit development and ripening physiology.

Horticultural Reviews 10, 229–271.

Téliz, D. (coordinator) (2000) El aguacate y su manejo integrado. Ediciones Mundi Prensa,

México, Madrid, Barcelona (in Spanish).

Whiley, A.W. and Scha er, B. (1994) Avocado. In: Scha er, B. and Andersen, P.C. (eds)

Handbook of Environmental Physiology of Fruit Crops Vol. II: Subtropical and Tropical

Crops. CRC Press, Boca Raton, Florida, pp. 3–35.

Whiley, A.W., Saranah, J.B., Cull, B.W. and Pegg, K.G. (1988). Manage avocado tree

growth cycles for productivity gains. Queensland Agriculture Journal 114, 29–36.

Whiley, A.W., Scha er, B. and Wolstenholme, B.N. (2002) The Avocado: Botany, Production

and Uses. CABI Publishing, Wallingford, UK.

Woolf, A.B., White, A., Arpaia, M.L. and Gross, K.C. (2004) Avocado. In: USDA-ARS

Handbook #66. (http://www.ba.ars.usda.gov/hb66/034avocado.pdf – accessed 7

Feb 2010).

Table 7.7. Proximate analysis of avocado (Wenkam, 1990).

Halumanu

West Indian type

Nabal

Guatemalan type

Water (g) 82.8 69.9

Energy (kJ) 431 874

Protein (g) 1.5 1.03

Lipid (g) 9.3 21.8

Carbohydrate (g) 5.7 6.3

Fibre (g) 1.6 2

Ash (g) 0.8 0.9

Minerals

Calcium (mg) 8 77

Iron (mg) 0.5 0.4

Magnesium (mg) – –

Phosphorus (mg) 34 42

Potassium (mg) – –

Sodium (mg) – –

Vitamins

Ascorbic acid (mg) – 5.5

Thiamine (mg) 0.03 0.09

Riboﬂ avin (mg) 0.09 0.14

Niacin (mg) 1.23 –

Vitamin A (IU) – 802

Amounts are per 100 g.

(R.E. Paull and O. Duarte)

BANANA AND PLANTAIN

Banana is a general term that refers to all wild species, landraces and cultivars

belonging to the family Musaceae, genus Musa (Ortiz, 2008). The commercial

banana is a giant, perennial, herbaceous monocotyledon, propagated

vegetatively; it is important in the humid tropical lowlands, with year-round

fruit production, but it can also grow in certain subtropical areas. The fruit

is served as a dessert (banana) or cooked and eaten as a staple (plantain).

The banana (English) has various names: bananier (French), pisang (Malay,

Indonesian), kluai (Thailand), chuoi (Vietnam), xiang jiao (Chinese).

The most important type of fruit commercially is the dessert banana,

which is eaten fresh and makes up most of the international trade of this

genus. The second most important group is the plantain, which is an

important staple food in many countries in Africa, Latin America and South-

east Asia, where extensive areas are grown mainly for local consumption.

There are also the East African highlands and the Asian cooking bananas, and

ﬁ nally the East African beer bananas. In some cases, the same genomic group

can include varieties used as plantains or as dessert bananas.

BOTANY

The genus Musa has more than 50 species, with some of these species having

numerous subspecies. This diversity has lead to the genus being divided into

three sections from the ﬁ ve traditional sections: Musa (2n = 22, incorporating

Rhodochlamys), Callimusa (2n = 20, incorporating Australimusa) and single-

species section Ingentimusa (2n = 28) (Wong et al., 2002). Among these

sections, there are wild, seeded plants and edible clones, with overlapping

geographical distributions. Ensete, the other genus in the family, ranges from

Asia to Africa, while Musa ranges from Africa through Asia to the Paciﬁ c

(Reynolds, 1951).

186 Chapter 8

Genus Musa

Edible bananas are derived from either Musa acuminata (A) or Musa balbisiana

(B), or a combination of both. Cultivars are diploid or triploid, with some new

tetraploids developed by breeding. Considerable somatic variation has led to a

great range of cultivars. Cultivars are described by their name and genomic

make-up, e.g. ‘Pisang Raja’ AAB, the AAB indicating that it is a hybrid with

two genomes of A and one genome of B. Most dessert bananas are AA or AAA,

with the triploid AAA being the most important in the trade. The di erent

groups and subgroups have somewhat distinct fruit characteristics (Table 8.1).

M. acuminata has a number of morphological characters that separate it

from M. balbisiana. For example, M. acuminata has an open petiolar canal, which

in M. balbisiana is closed. M. acuminata has prominent bract scars, bracts that

Table 8.1. Fruit characteristics of some major cultivars within groups and subgroups.

Group Subgroup Characteristics

AA Sucrier Small fruit (8–12 cm long), thin golden skin, light orange

ﬁ rm ﬂ esh, very sweet, 5–9 hands per bunch, 12–18

ﬁ ngers per hand

Lakatan Medium to large straight fruit (12–18 cm), golden yellow,

ﬂ esh light orange, ﬁ rm, dry, sweet and aromatic, 6–12

hands per bunch, 12–20 ﬁ ngers per hand

AAA Gros Michel Medium to large fruit, thick skin, creamy white ﬂ esh,

ﬁ ne-textured, sweet and aromatic, 8–12 hands/bunch.

Susceptible to Panama disease

Cavendish Medium to large fruit, yellow skin, white to creamy ﬂ esh,

melting, sweet, aromatic, 14–20 hands per bunch,

16–20 ﬁ ngers per hand. Susceptible to Race 4 of Panama

disease

AAB Silk Small to medium yellow fruit (10–15 cm), thin yellow-

orange skin, white ﬂ esh, soft, slightly subacid, 5–9 hands

per bunch, 12–16 ﬁ ngers per hand, skin frequently has

blemishes

Pisang Raja Large fruit (14–20 cm), thick skin, cooking banana, creamy

orange ﬂ esh, coarse texture, 6–9 hands per bunch, 14–16

ﬁ ngers per hand

Plantain Yellow skin, creamy orange ﬁ rm ﬂ esh, few hands per

bunch

ABB Bluggoe Medium to large cooking banana, thick coarse skin turns

brownish-red when ripe, creamy orange ﬂ esh, starchy, 7

hands per bunch

BBB Saba Stout, angular, medium to large cooking banana (10–15

cm), thick yellow skin, creamy white ﬂ esh, ﬁ ne-textured,

8–16 hands per bunch, 12–20 ﬁ ngers per hand

Banana and Plantain 187

are lanceolate and curl, and two regular rows of ovules, compared with four

irregular rows in M. balbisiana. Using and scoring 15 morphological characters

allows the relative contribution of the two species to be determined in hybrid

cultivars. Triploids and tetraploids are larger and more robust than diploids.

Origin and distribution

The primary centre of origin is thought to be Melanesia (Malaysia, Indonesia,

the Philippines, Borneo and Papua New Guinea); M. acuminata Colla. has

seeded fruit. Dessert cultivars were developed from it via parthenocarpy and

sterility, aided by human selection and vegetative propagation. M. balbisiana

Colla. also has a wild, seeded fruit, is more suited to drier areas and occurs

from India to New Guinea and the Philippines, though absent from central

Melanesia (Espino et al., 1992). It was similarly taken into cultivation, with the

selection of natural diploid, triploid and tetraploid hybrids.

ECOLOGY

Soil

Deep friable loams with natural drainage and no soil compaction are preferred.

Soils with poor percolation due to excess of clay or with an excessive amount

of sand should be avoided, as well as soils with high amounts of gravel. Soils

having pH between 4.5 and 7.5 are used, although 5.8–6.5 is recommended.

Soil textures ranging from sands to heavy clays are used. A granular soil

structure is the preferred for better water movement and root growth, with

high organic matter and fertility ensuring high yields. Most exported bananas

are produced on highly fertile alluvial loams. Plantains also do best in this type

of soils, but they will do better than the AAA dessert banana in lower-quality

soils; apparently the ‘B’ in their genome is responsible for this adaptability.

Soil depth should be around 1.0–1.2 m, with no superﬁ cial water tables or

impermeable layers. Soil drainage is essential since, although the plant prefers

moist soil, it does not tolerate standing water. Flooding for a week will kill most

banana plants (Duarte, 1991). Banana will tolerate some salinity: 300–350

mg/l of chlorine and up to 1500 ppm total salts.

Climate

Rainfall

Bananas require a regular water supply that matches or slightly exceeds the

free-water evaporation rate. Irrigation is essential for high yields if rainfall is

less than evaporation and it also provides the advantage of fertilization via the

188 Chapter 8

irrigation water. Areas with very high rainfall may be too overcast for optimum

photosynthesis, have more disease problems and require extensive drainage.

The plantain group is less susceptible to water stress than dessert bananas

(Belalcazar, 1991), and this is another reason why small farmers grow them

around their houses. Plantains do well with about 30 mm weekly rainfall in

the co ee region of Colombia.

Temperature

A temperature range of 15–38°C occurs in most production areas, with

the optimum temperature being ~27°C. The optimum for dry-matter

accumulation and fruit ripening is about 20°C and for the appearance of

new leaves about 30°C. Growth ceases at 10°C and can lead to ‘choke-

throat’ disorders, where inﬂ orescence emergence is impeded and poor fruit

development occurs. Temperatures less than 15°C can be withstood for short

periods, while temperatures less than 6°C cause severe damage (Turner,

1994), and temperatures below 4°C result in irreversible damage. Frost

causes rapid death. At temperatures above 38°C growth stops and leaf burn

occurs. Plants growing in the subtropics produce fewer leaves per year than

those in the tropics and take longer to produce and develop fruit (Table 8.2).

Sucker emission and development are also slower. Bananas grown at higher

elevations that have lower temperatures tend to produce sweeter fruit, because

of cooler nights. In certain cooler areas, such as the Canary Islands, bananas

are produced in plastic greenhouses.

Plantains and cooking bananas are grown at sea level but also at higher

elevations in Latin America, Asia and Africa. In many cases, they are grown

as subsistence crops and are planted even at 2000 m above sea level in places

where mean minimum temperatures are not below 15°C and the absolute

minimum does not drop below 8°C. Clonal di erences do occur in the ability

to adapt to cooler temperatures. In Colombia, an important producer of

plantains, commercial production occurs from sea level to 1350 m, though

clones such as ‘Harton’ are not planted above 800 m. Lower temperatures

Table 8.2. Phenological differences between cultivars of Cavendish subgroup

ratoon plantation in the humid tropics (Honduras: cv. ‘Grand Nain’, Stover and

Simmonds, 1987) and subtropics (South Africa: cv. ‘Williams’, Robinson and Nel,

1985; Robinson and Human, 1988).

Humid tropics Subtropics

Mean number leaves per month (warm/cool

season)

3.5/2.5 4/0.5

Total leaves per year 40 25

Planting to harvest (months) 9–11 15–20

Harvest to harvest (months) 6–8 11–13

Flowering to harvest (warm/cool season, days) 98–117 120–204

Banana and Plantain 189

do reduce yields signiﬁ cantly, making commercial production uneconomic. It

is estimated that the vegetative cycle is extended by 10 days for every 100 m

increase in elevation (Belalcazar, 1991). At higher elevations, the form of the

fruit bunch changes, with hands becoming more separated.

Wind

Bananas and plantains are very susceptible to wind damage. In all producing

regions, moderate winds between 20 and 50 km/h cause moderate to severe

tearing of the leaves. This leaf-tearing can reduce productivity, but as long

as there is no signiﬁ cant loss of foliar surfaces, it does not normally have a

major e ect. This tearing does reduce plant transpiration when maximum

daily water stress occurs, while net photosynthesis is little a ected (Belalcazar,

1991), giving higher photosynthetate production by unit of water transpired.

This beneﬁ cial e ect may be important during the dry season. The problem

with winds above 50 km/h

is that they cause loss of leaf pieces, break the

pseudostem or uproot the plants, in the latter two cases the crop is lost until

the ratoon suckers complete their cycle. In certain areas of Central America,

a phenomenon called ‘blow down’ is frequent; this is caused by gusts of

high-velocity winds that unexpectedly hit certain areas and break all tall

pseudostems, producing almost the same e ects as a hurricane but in a

limited area.

Light

For dessert bananas, as well as for plantains, solar radiation should be as

high as possible for best growth and yields, although fruit sunburn can occur,

especially if water supply is low; petioles can also be burnt. Shaded or overcast

conditions extend the growth cycle by up to 3 months and reduce bunch size

(Fig. 8.1). For plantains grown under lower radiation levels, the plants tend to

be taller. Plant density plays a role in relation to light, since denser plantings

intercept more light at the top but there will be less radiation at ground level,

reducing sucker production.

Photoperiod

No evidence exists that photoperiod inﬂ uences ﬂ owering. Increasing the

photoperiod from 10 to 14 h increases the rate of new leaf appearance,

probably due to more photosynthesis.

GENERAL CHARACTERISTICS

Plant

This 2–9 m perennial herb has an underground, compressed stem or corm

that is the real stem. The visible part that looks like a stem (pseudostem)

190 Chapter 8

consists of overlapping leaf sheaths. The apical bud of this corm produces the

leaves, and at certain stage it di erentiates into the ﬂ ower bud, which, in the

same way as the leaves, grows up through the centre of the pseudostem until

it emerges at ﬂ owering (Fig. 8.2).

The corm has lateral buds that produce shoots (suckers) near the parent

(Fig. 8.2). These suckers grow and, when old enough, ﬂ ower and bear fruit

and are the basis for the successive ratoon crops that these plants normally

produce for many years. Suckers can be of two types: the ‘sword’ sucker is one

that has very narrow leaves when young and its pseudostem has a conic form;

the other type is the ‘water’ sucker, which has a cylindrical pseudostem and

wide, almost rounded leaves. ‘Water’ suckers are eliminated in the plantation

and normally are not used for propagation, while ‘sword’ suckers are selected

to become the ratoon crop and preferred as propagation material, although

trials with plantain (Belalcazar, 1991) have shown that ‘water’ suckers can

result in an equally productive crop if given proper care when young.

Adventitious roots that arise from the corm form a dense mat and spread

extensively 4–5 m from the parent and down to 75 cm or more. Plantains of

the AAB genome have a shallower root system than export bananas.

The large leaf lamina are 1.5–4 m long by 0.7–1 m wide, with pronounced

midribs and parallel veins (Fig. 8.2). Stomata occur on both surfaces, with

Fig. 8.1. Effect of shading on the bunch weight produced per month (kg/month

and months to harvest). Low light reduces the leaf area produced, and a positive

relationship exists between leaf area of the third mature leaf and ﬁ nal bunch weight:

y = 4.83x – 12.83. r

= 0.75, signiﬁ cant at P < 0.05 (after Murray, 1961).

Banana and Plantain 191

(a)

(b)

(c)

(d)

(e)

Seed

Fig. 8.2. Plant, leaves and bunch (a), ﬂ oret (b), young fruit (c), and transverse

section of seedy fruit (d) and the more common seedless fruit (e) of banana. The

hands of seedless fruit are cut from the bunch stem, leaving a portion of the stem

that is called the crown.

192 Chapter 8

three times more on the adaxial surface. The leaf takes 6–8 days to fully unroll

from the tip, and in the tropics the leaves last c. 50 days. Leaves emerging

just before the inﬂ orescence can live up to 150 days or more. Twenty-ﬁ ve to

50 leaves emerge, with 10–15 functional leaves present (total area 25 m

)

at inﬂ orescence emergence. The number of leaves at ﬂ owering is positively

correlated with bunch weight (Fig. 8.3); fewer than six to eight leads to

signiﬁ cant reduction in bunch weight. After ﬂ ower emergence, no more leaves

are produced, so the plant should have as many as possible functional leaves

at this time. The main problem with the major leaf disease Sigatoka is that it

reduces the number of functional leaves and their useful area.

Flowers

One terminal inﬂ orescence emerges through the pseudostem and bends

downwards after emergence (Fig. 8.2). The ﬂ owering spike consists of groups

of two rows of appressed ﬂ owers enclosed within large, ovate, reddish bracts

at each node. The bracts reﬂ ex and are shed as the fruit develop. The female

ﬂ owers emerge ﬁ rst and the males at the distal end. Sometimes hermaphrodite

ﬂ owers develop in the middle of the bunch, but they generally abscise.

Flowers at each node are referred to as a hand; each hand has 12–20 ﬂ owers

per node and there are 5–15 hands with female ﬂ owers. The bracts open

sequentially, about one per day. The peduncle continues to elongate up to

1.5 m, terminating in a male bud, which continues to produce male ﬂ owers

enclosed within the bracts. The last hand (false hand) of the female ﬂ owers

Fig. 8.3. The effect of number of functional leaves at ﬂ owering on bunch weight

(redrawn from Turner, 1970).

Banana and Plantain 193

has few ﬁ ngers (fruit) and the rest of the nodes have non-functional pistils.

The inﬂ oresence stem (rachis) is cut below the false hand, where a ﬁ nger is

left attached to maintain a connection with the plant circulatory system and

avoid rachis rotting. The detached rachis removes the male ﬂ owers. In plants

with no false hands at the time of fruit thinning, a ﬁ nger will be left in the last

hand.

The 10 cm female ﬂ owers of cv. ‘Cavendish’ have an inferior ovary of

three united carpels with a short perianth. The perianth consists of ﬁ ve fused

and one free segment, forming a tube around the style and sterile androecium

and three-lobed stigma. Male ‘Cavendish’ ﬂ owers are 6 cm long with ﬁ ve

stamens, which rarely bear fertile pollen.

Pollination and fruit set

Natural pollination

The fruit develops parthenocarpically. The ovules shrivel early and are

recognized as brown specks in the mature fruit along the axial placenta (Fig.

8.2). Very infrequently, seeds are found in mature fruit of edible cultivars,

especially those with a ‘B’ genome. The ‘Cavendish’ group has absolute female

sterility with few viable pollen. The ‘Gros Michel’ (AAA) dessert banana

produces seed once in a while and therefore is used as the female parent in

many crosses. ‘Pisang Awak’ (ABB) can sometimes be very seedy if pollen-

bearing diploids are growing nearby.

Floral induction and fruit set

There are no external symptoms of the start of inﬂ orescence development.

The ﬂ owering stimulus is unknown. Externally, it is not temperature or

photoperiodism, and internally it is not the number of leaves developed,

as the number of leaves is more or less ﬁ xed, depending on cultivars and

environment.

Fruit morphology

The fruit, although it develops from an inferior ovary, is a berry. The exocarp

is made up of the epidermis and the aerenchyma layer, with the ﬂ esh being

the mesocarp (Fig. 8.2). The endocarp is composed of a thin lining next to

the ovarian cavity. The axial placenta has numerous airspaces and ventral

vascular bundles.

Each node of the rachis has a double row of ﬂ owers, forming a cluster

of fruit that is commercially called a ‘hand’, with the individual fruit called a

‘ﬁ nger’. ‘Cavendish’ bananas can have 16 hands per bunch, with up to about

30 ﬁ ngers per hand, and the bunch can weigh up to 70 kg. There are many

194 Chapter 8

di erent sizes and shapes of fruit, with plantains being usually very large

compared to the dessert-type bananas or others. The same is true for external

and pulp colour, which normally vary from cream to slight orange.

Growth and development

Pollen sterility is due to triploidy, while female sterility is due to at least

three complementary dominant genes and modiﬁ er genes. These sterility

genes are found in wild populations and have been selected for fruit edibility.

Parthenocarpy is separate from sterility. For the ﬁ rst fortnight after anthesis

the ovules increase in size (50% over initial), and later they shrivel and ovary

growth slows. Parthenocarpic bananas that have seeds (‘Pisang Awak’ ABB)

show a stimulation of fruit growth, due to the presence of developing seeds.

Pollination can stimulate fruit growth, even without seed development (Israeli

and Lahav, 1986).

There are periclinal and anticlinal divisions from 6 weeks before

inﬂ orescence emergence (anthesis) to 4 weeks after emergence. This division

is followed by cell expansion for 4–12 weeks after emergence. Skin mass

increases rapidly in the ﬁ rst 40 days after ﬂ owering, with the fruit pulp not

beginning to develop until day 40 (Fig. 8.4). Starch accumulation parallels

ﬁ nger length and diameter increases (Lodh et al., 1971). The fruit matures

in the tropics 85–110 days after inﬂ orescence emergence. Fruit development

may take up to 210 days in the cooler subtropics or under overcast conditions

(Table 8.2). Harvest maturity is a commercial stage (three-quarters round),

with the fruit still having some angularity and being only 75% of its potential

maximum size. Export bananas are harvested in the tropics at 14–15 weeks

after ﬂ ower emergence, while plantains are harvested after 11–12 weeks. Fruit

allowed to fully develop to a round shape may show skin splitting. Depending

upon the persistence and viability of the remaining leaves, fully developed fruit

may also show sunburn.

Since fruit number and size decrease from the proximal to the distal

(bottom) hands, fruit thinning is sometimes practised. In most cultivated types,

the bunches bend because of the fruit bunch weight. As the inﬂ orescence

emerges from the pseudostem, it bends towards the sun. Fruits on the inner

whorl of a hand can be 15% smaller than those on the outer whorl. Normally

the last or last two hands that have smaller hands are eliminated if higher fruit

calipers (diameters) are desired. The male inﬂ orescence can be removed soon

after full development of the bunch without damaging the female hands; this

removal reduces the weight and can, in some instances, slightly increase the

caliper of the remaining fruit.

In plantains, there are normally fewer ﬂ owers per bunch, although some

of the new tetraploids have a very heavy load of fruit. Some plantain types do

not have the male part of the inﬂ orescence or it is rudimentary.

Banana and Plantain 195

CULTIVAR DEVELOPMENT

Genetics and cytogenics

The haploid number is n = 11, with 22, 33 and 44 chromosomes being found

in the diploids, triploids and tetraploids. There are 200–300 clones, of which

more than half are triploids. Triploids are more vigorous, easier to grow and

higher yielding than diploids (Gowen, 1995). Some tetraploids have been

developed that have desirable characteristics such as Sigatoka tolerance and

high yields.

Problems in breeding

The majority of breeding e orts have been directed at the AAA group, because

the group has the highest export potential. However, female sterility and the

low numbers of viable pollen make conventional breeding very di cult. Some

inferior cultivars can, under controlled conditions, produce seeds; however,

it takes 3 years from seed to seed. In the Honduran breeding programme of

the Honduran Agricultural Research Foundation (Fundación Hondureña de

Investigación Agricola, FHIA), the AAA ‘Gros Michel’ dessert banana is used

in many instances as the female parent for crosses, as some fruits have seeds.

Fig. 8.4. Growth of ﬁ nger, pulp and skin fresh mass of ‘Gros Michel’ in the

Caribbean (Simmonds, 1982).

196 Chapter 8

After a cross with ‘Gros Michel’ as female parent, the hybrid seeds are extracted

by ripening large numbers of these fruits derived from the cross, peeling them

and passing the pulp through a strainer that retains the few seeds present.

Considerable breeding e orts and selection of crossed material may

lead to the development and release of cultivars with suitable horticultural

characteristics and increased disease resistance (Gowen, 1995). Apart from

the e orts supported by the International Network for the Improvement

of Bananas and Plantains (INIBAP) (Vuylsteke et al., 1993), there have

been a few e orts to develop better varieties for small and medium-sized

growers serving local markets with local varieties in Brazil, Africa and India.

In Honduras, FHIA has produced a complex pedigree hybrid (FHIA 03), a

‘Bluggoe’ type of cooking banana, resistant to black Sigatoka, ‘Moko’ and

Panama disease, which is planted in East and West Africa, and in Cuba by

small farmers. They have also released ‘FHIA-25’, another AAB cooking

banana, as well as ‘FHIA 21’, a plantain, both are resistant to black Sigatoka.

Selection and evaluation

Considerable e orts have been expended in characterizing various cultivars

under comparable conditions (Rowe and Rosales, 1996). Somaclonal variation

and mutation breeding is widely used. The focus of these programmes is

resistance to black Sigatoka, Fusarium wilt (Panama disease), bunchy-top virus

and nematodes. Gene transfer from unrelated species also o ers considerable

opportunities for improved planting materials. Besides selection for resistance

to the above diseases, other priorities include resistance to the weevil that

bores into the corm, dwarﬁ sm, tolerance to drought and cold, and improved

bunch yield, harvest index, fruit quality (texture and ﬂ avour) and storability

(Novak, 1992). Similar priorities exist for plantains, with susceptibility to black

Sigatoka and low bunch yield being the major limitations, followed by some of

the same priorities as for dessert bananas. New plantain types have been easier

to produce than dessert bananas and some are being grown extensively in

many tropical areas.

Major cultivars

There are at least 200–300 banana clones in various countries, many

having di erent names in di erent localities (Table 8.3). There are numerous

germplasm collections around the world, including those in Indonesia,

Malaysia, Thailand, the Philippines, India, Honduras, Jamaica, Brazil,

Cameroon and Nigeria. The large number of synonyms for many of the better

cultivars makes for some confusion (Lebot et al., 1993).

Banana and Plantain 197

Table 8.3. Major genomic groups and some cultivars. The seedless diploid (AA) and triploid (AAA) are regarded as desserts, while the

seedless diploid (BB) and triploid (BBB) are cooking bananas. These and the many hybrids are all referred to as Musa spp., followed by

the code and subgroup (SG) name (Cavendish, Gros Michel, plantain, etc.).

AA AAA AAB ABB BBB Other

Sucrier syn. Gros Michel (SG) syn. Silk syn. Pisang Awak (Indo,

Mal), syn.

Saba (Phil), syn Atan (AAAB), AA

Pisang Mas (Mal,

Indo)

Blueﬁ elds Apple (Hawaii) Ducase (Aust) Cardaba (Phil) Kalamagol (AABB)

Kluai Khai (Thai) Pisang Ambon (Mal) Pisang Rastali (Mal) Katali (Phil) Kluai Hin (Thai) Gold Finger (AAAB)

Amas (Aust) Disu Pisang Raya Serek

(Indo)

Kluai Namwa (Thai) Pisang Nipal (Mal)

Susyakadali (India) Kluai Hom Thong

(Thai)

Latundan (Phil) Pisang Klotok (Indo)

Lakatan (Phil), syn. Cavendish (SG) Woradong Kanpuravalli (India)

Pisang Barangan

(Indo)

Dwarf Cavendish, syn. Cantong Bluggoe, syn.

Pisang Herangan

(Mal)

Chinese (Hawaii) Tundan Pisang Kepok (Indo)

Senorita Canary Banana Lady Finger, syn. Pisang Abu Keling

Dwarf Chinese Pome Pacha

Naadan

Kluai Hak Muk (Thai)

Basrai (India) Pisang Raja (Mal,

Indo)

Nalla Bontha (India)

Governor (West Ind)

syn.

Radja (Phil) Moko (Trinidad)

Enano (Latin Amer) Larp Da Jiao (China)

Giant Cavendish, syn. Houdir Fen Da Jiao (China)

Continued

198 Chapter 8

Table 8.3. Continued.

AA AAA AAB ABB BBB Other

Mons Mari (Old) Mysore (India), syn.

Williams (NSW) Colombo

Grand Nain Poovan (India)

Bongali Johaji (India) Honderawala

(India)

Beijiaw (China) Plantain (SG)

Honchuchu Horn, syn.

Pisang Ambon Putih

(Malay), syn.

Pisang Tanduk

Kluai Horn Dek Mai

(Thai)

Tindok

Ambon (Phil) French, syn.

Pisang Embun Nendran (India)

Banana and Plantain 199

CULTURAL PRACTICES

Propagation and nursery management

Sexual

Seeds are only used in breeding programmes. Many of the important

commercial cultivars are female-sterile.

Asexual

Suckers with their basal corm or entire corms are used as planting material.

A sucker is a lateral shoot that has a basal corm and a short pseudostem that

arises at the base of a plant from the mother corm. Suckers are normally used

by small farmers or when few plants are needed. The di culty with suckers

is their size, which makes handling and transportation di cult. In addition,

disinfection, which is essential to avoid transporting insects, disease and

nematodes, is often ine ective. A young sucker just emerging from the soil or

a large sucker with narrow leaves and a large corm are normally planted with

the remaining roots at the same depth as they were originally, and the excess

leaves will be pruned back.

The banana exporting companies normally use corms that are at the

base of a plant that has not ﬂ owered and that was raised in special nursery

ﬁ elds; these corms will have a weight of 2.5–5 kg. In other cases, 1.6–1.8 m

tall sword suckers that have a diameter of 15–20 cm at 20 cm from the soil

are used. The suckers are dug out and 15–20 cm of the pseudostem retained.

Sometimes large, older corms (bull heads) from plants that have ﬂ owered can

be used for planting if propagation material is scarce. Smaller pieces of corms

can also be used.

The ideal is to disinfect the corms. The corm is pared so no dark spots and

roots are left, and the pared corm is dipped in a mix of a fungicide, nematicide

and insecticide for 5–20 min. The large exporting companies use a hot water

dip at 56–58°C for 15–20 min or 65°C for 12–15 min. If no pesticides

are available or are not allowed, simply paring the corms is helpful to limit

transfer. Corms to be used for planting should never be left overnight on the

ground, they should be either covered tightly or put on a trailer or truck, to

avoid reinfestation by banana weevil.

When propagating material is scarce, several techniques can be used to

increase the number of suckers. A sucker is planted and, before it di erentiates

a ﬂ ower bud, several practices can be used to prevent further growth of the

apex and induce axillary bud growth. One practice is to drive a stake into the

pseudostem at a 45° angle, aiming to destroy the apical meristem, or a coring

tool is used to achieve the same objective. Another technique is to partially cut

the pseudostem before ﬂ owering at about 1.5 m from the ground, so the top

will bend and it will look like a ‘7’, or to cut it down; in other cases the outer

200 Chapter 8

leaf sheaths are pulled down to the bottom of the pseudostem, in order to

expose the axillary buds, and then soil is mounded around the base. All these

practices prevent ﬂ owering, and induce axillary bud growth that develops into

numerous suckers.

For high-density plantain plantings developed in the last decade in Central

America for the ‘Curraré Enano’ (AAB) plantain variety, the corms are graded

by size into three or four grades then planted in di erent areas to ensure ﬁ eld

uniformity. Larger corms, 500–2000 g, are planted directly into furrows in the

ﬁ eld in either a horizontal or vertical orientation. Smaller corms of 200–500

g are planted into plastic bags and kept for 6–8 weeks before grading by size,

with the larger corms planted into the ﬁ eld. The advantage of planting bagged

plants is that no ﬁ eld irrigation and weeding are necessary before planting out

and the growth in plastic bags means that a more uniform stand and no empty

spaces are obtained, as only sprouted suckers from the corm are planted. The

corms are pared and if possible disinfected before planting in the ﬁ eld or bags,

as for dessert bananas.

Tissue culture (in vitro plantlets) allows for rapid multiplication of

uniform, disease-free materials (Loyola Santos et al., 1986). Other advantages

of tissue culture include very high ﬁ eld establishment rates, uniformity of

harvest timing, precocity and high production, at least in the ﬁ rst crop cycle.

These advantages have to be balanced against higher cost, extra care at

multiplication and the transmission of viruses that have not been eliminated.

Somatic variation is the major problem and care in multiplication is necessary

to reduce the incidence to an acceptable level (<3%) (Smith, 1988).

Field preparation

The ﬁ eld should be ripped, ploughed and disced before planting. This

may involve cross-ripping to 1 m to break up any soil compaction. Lime,

phosphorus (P) and potassium (K), as determined by soil analysis, should be

added at this time. Sloping land should be prepared so as to avoid erosion.

Drainage is vital to avoid waterlogging, which can reduce yields. The water

table should be kept below 1.2 m in depth. Extra drainage can be installed

during ﬁ eld preparation via trenches and drains. Drainage preparation can be

a fairly expensive task in the export banana production ﬁ elds, as the ﬁ elds are

expected to remain in production for many years. In Chapter 3, there is a brief

description of these drainage systems.

Transplanting and spacing

A planting hole slightly larger than the material is dug or a furrow made. The

corms are usually covered with 10–15 cm of soil. Planting is scheduled in

Banana and Plantain 201

subtropical areas to meet certain harvest periods in the ﬁ rst crop cycle (Galán

Saúco, 1992). Also in the subtropics, the late summer through to the winter

is avoided, so as not to expose young plants to low temperatures. The concern

in the tropics is to avoid hot weather or a dry season; hence, the best time for

planting is just before the wet season. In hurricane-prone areas, planting is

done before the hurricane or typhoon season, so that the plants are still short

and less prone to being blown over.

Planting densities from 1000 to 3000 plants/ha are used in triangle,

rectangle, single- or double-row cropping patterns. Double rows combine

higher density with a 3.5 m alley for access. The actual density depends upon

cultivar and climate. Higher densities are used in hot, dry localities to generate

the necessary shade and microclimate for maximum yields. The vigour of a

plantation is related to the canopy characteristics, leaf area index and yield.

If only one growth cycle is to be used, a higher density may be planted (3000

plants/ha), for three or more growth cycles; a lower density is recommended

(2000 plants/ha) for highest gross margin.

Export bananas are usually planted in equilateral triangles or in double

rows; in a few cases a square arrangement that is 2.4 m × 2.4 m is used.

The equilateral triangle (hexagonal) system allows for a better use of space;

normally the sides of the triangle are 2.5 or 2.7 m, resulting in 1800–2000

plants/ha. In the double-row system, two closely planted rows are separated

by a wider space from the next double row. The double rows are 1 m apart; the

plants are at 2.25 m in the row and 3.75 m is left between the double rows,

giving a total of 1840 plants/ha. This system allows for the movement of small

equipment in the ﬁ eld and makes harvest easier by allowing a cable system

to be set up parallel to the double-planted rows, from which the bunches are

hung with strings to avoid the pseudostems from falling over because of the

fruit weight and damaging the bunch.

Orientation of double rows N to S or E to W does not signiﬁ cantly e ect

yield (Belalcazar, 1991). More important is to orient rows to avoid erosion in

ﬁ elds planted on a slope and wind damage from the prevailing winds.

High-density annual plantings

In recent years, especially with plantains, a system using high-density planting

and a single harvest developed in Colombia (Belalcazar, 1991) is now being

used in Central America (Lardizabal and Gutierrez, 2006). The ﬁ eld is prepared

and planted in double or single rows in a rectangular arrangement, with 3333

to around 4000 plants/ha. To achieve 3333 plants in the double-row system,

there would be 1.2 m between the twin rows and 1.5 m in rows, with 2.8 m

between the double rows. In single-row arrangement, the plants are 1.50 m

in row and 2.0 m between rows. For 4000 plants/ha, the distances between

double rows and single rows are reduced. When 50–60% of the plants are

202 Chapter 8

harvested, the new planting can be started with corms or plants in bags

planted into the space between the double or single rows; once harvest has

ﬁ nished the old plant stumps are eliminated. The big advantage of this, aside

from higher yields, is that harvest time can be decided in advance, to avoid

harvesting and marketing fruit when market prices are depressed because of

oversupply. Additionally, since plants become more susceptible to Sigatoka

after ﬂ owering, a high-density planting system limits disease incidence in the

ﬁ rst part of the cycle and reduces the need to spray for disease control. The

system is more appropriate for plantains, which normally do not last as long

planted in the ﬁ eld as export bananas, and are normally replanted after two or

three harvest cycles. If a ﬁ xed harvest season is important, the new planting

can be done in a di erent ﬁ eld if the original ﬁ eld is not ready for replanting.

The system has also been successfully implemented for dessert bananas.

Cableway

Cableways are an important innovation in banana harvesting and handling

by the large banana exporters. The cableway greatly reduces mechanical

injury to the fruit during transportation to the packing house. It is also used to

take fertilizers and other materials to the ﬁ elds. When ‘Gros Michel’, a tough-

skinned variety, was replaced because of Panama disease by ‘Valery’ and later

‘Grand Nain’, as both clones have delicate skins, it gave the impetus to use

cableways, as well as the use of packing boxes for export fruit.

Irrigation practices

Irrigation water can be supplied by furrow or over-canopy sprinkler, with

drip irrigation and micro-sprinklers becoming more popular. Irrigation is

used to supplement rainfall and its scheduling requires a calculation of

amount and frequency. This schedule is based on pan evaporation, soil water-

holding capacity, banana root depth, water depletion and crop water use.

The important characteristics of banana are its: (i) high water-loss potential,

associated with its large, broad leaves; (ii) shallow root system – c. 90% of

roots are in the top 300 mm; (iii) poor ability to absorb water from a drying

soil; and (iv) rapid physiological response to water deﬁ cit. Soil water potentials

more negative than −20 to −40 kPa can adversely a ect growth, with relative

impact depending upon local climate – hot and dry (severe impact) to moist

and humid (less impact). In the case of plantains, the same is true; however,

plantains are slightly more tolerant of water scarcity than dessert bananas,

but yield can be depressed by drought.

Micro-sprinkler use has become popular with banana and plantain

exporters in Latin America. Sprinklers are spaced ~11 m from each other,

Banana and Plantain 203

in a square arrangement, on a riser at about 70–80 cm above the soil level.

This system o ers many advantages, the main being the use of less-powerful

pumping equipment than required for the large cannons, which would cover

about a hectare, previously used. The micro-sprinklers, being below the

canopy, do not splash water from one leaf to another and thus prevent the

spread of fungal diseases like Sigatoka. In recent years, drip irrigation has

shown promise, though vandalism from labourers or neighbours who cut the

hoses and steal them is a problem for small producers. Drip irrigation works

very well in well-managed plantations with ﬁ eld security.

Pruning and bunch propping

Other than removal of the male inﬂ orescence, no other vegetative pruning

is normally practised. Withered styles and perianths persisting at the end

of the fruit are usually removed at the packing station after harvest, but are

sometimes removed by hand 8–12 days after the bunch emerges, to reduce

fruit scarring and disease (cigar-end rot). Early removal of one or more hands

from the distal end of the bunch is practised to increase fruit size by reducing

inter-ﬁ nger and hand competition. This hand removal is done by the exporting

companies for dessert bananas and plantains to achieve better calipers (fruit

diameter – size) in the remaining fruit.

Bunches falling from the plant or the whole plant falling over can lead to

considerable bunch damage and can lead to rejection of the a ected fruit for

export. Lodging is due to poor corm anchorage, poor planting material or very

large bunches. The problem is reduced if single or double poles are wedged

against the throat of the plant under the curvature of the bunch peduncle or

twine guys are extended from this same point in the opposite direction of the

fruit bunch and tied to lower positions on nearby plants.

Sucker management and leaf removal

Sucker management is an essential step to remove unwanted suckers

developing from the base of the parent corm and to select a suitable sucker

to produce the ratoon crop. The strategy is to remove suckers that receive

nutrients from the parent plant and which would extend its cycle and reduce

its yield if they remained (Fig. 8.5). This operation is vital in the subtropics.

Desuckering is done by hand by cutting and gouging every 4–8 weeks,

and para n-oil injection so that suckers do not use too many of the resources

available to the parent (Fig. 8.5). Selection of ratoon suckers is critical to

maintaining yield, production and appropriate plant spacing. A sucker on the

most open side is usually selected as the daughter plant and left as the follower,

taking into consideration ﬁ eld spacing. The plants ‘walk’ since the ratoon

204 Chapter 8

comes at the side of the original plant; therefore care has to be taken that all

plants ‘walk’ in the same direction by carefully selecting the ratoon suckers

in order to keep the original distances between plants. Normally a machete is

used for this operation and care should be taken to disinfect it before every new

plant, to avoid transmission of bacterial diseases such as ‘Moko’.

Removal of dead leaves is practised to reduce disease spread and to prevent

senescent leaves from hanging over suckers and reducing light and to prevent

fruit scarring. At least six to eight healthy leaves should remain on the plant

at ﬂ owering to ensure maximum bunch development (Fig. 8.3). Plants with

severe leaf removal or damage (e.g. as a result of insect feeding) have reduced

bunch weights. The green life of the harvested banana is also reduced by

leaf loss.

Fertilization

Regular fertilization practices are followed on large commercial plantations

(15% of total world production) to maintain optimum productivity, while

in the less-intensively cultivated plantation less supplementary fertilization

occurs (Martin-Prevel, 1990). Deﬁ ciency symptoms have been described for

leaf blade and petioles. Mineral analysis of banana plants has been used and

Fig. 8.5. Effect of the amount of unwanted sucker growth of ‘Williams’ banana

before removal, on remaining sucker (follower) bunch mass, annual yield in the

ﬁ rst ratoon crop and the crop cycle duration between the ﬁ rst and second ratoon.

Unwanted suckers were removed when they were 30 cm, 50 cm and 80 cm high,

leaving one following sucker per plant mat. The leaf area of the 80 cm sucker was

39 times greater than the 30 cm sucker (redrawn from Robinson and Nel, 1990).

Banana and Plantain 205

ranges of deﬁ ciency and adequacy suggested. For plant growth and fruit

production, large amounts of nutrients are required. These nutrients come

from the soil and decaying plant material, and the remainder comes from

applied organic matter and fertilizer. The amount of nutrients removed by the

harvest of cv. ‘Cavendish’ fresh fruit with a yield of 50 t/ha/year includes 189

kg/ha nitrogen (N), 29 kg/ha P, 778 kg/ha K and 101 kg/ha calcium (Ca).

As a proportion of the total nutrients taken up by the banana plant, this is

equivalent to 49% of the N, 56% of the P, 54% of the K and 45% of the Ca.

These total amounts and proportions are about half of those for plantain

(Table 8.4). Most of the data have been derived from experimentation with

bananas produced for export, especially from varieties in the ‘Cavendish’

subgroup. Cultivar and subgroup di erences have been recorded, with the

optimum nutrient supply not being the same for all cultivars. Seasonal

inﬂ uences on fertilization are much greater on bananas growing in

the subtropics, where temperature probably has the greatest inﬂ uence.

Intercropping needs should also be considered.

The large N and K requirements are modiﬁ ed by the local soil nutrient

concentrations. The rate of application depends on climate, soil type, variety,

management practices and yield. Since vegetative and reproductive stages of

development are found in one ﬁ eld at the same time, and as the initial stages

of fruit inﬂ orescence development are crucial for ﬁ nal yield, a constant supply

of nutrients is essential for high yield. If the pseudostem is left standing

after bunch harvest, up to 40% of the nutrients (especially N, P and K) can

be removed by the following ratoon sucker (Fig. 8.6) and increase the bunch

weight of this next generation. Delaying fertilization can have a signiﬁ cant

impact on yield, reducing it by 40–50% or more; a 3-month delay makes it

di cult for the plants to recover.

Because of the extensive root system, fertilizer should be applied away

from the pseudostem, mostly on the side of the next ratoon. Solid fertilizer is

applied three to four times per year, more frequently if there is high rainfall,

for this a 60 cm semicircular strip of fertilizer 30 cm wide is broadcast 30–40

cm in front of the ratoon sucker. Fertilizer applied through irrigation water

(fertigation) is more e cient and gives better control of application time and

rate to meet demands. Frequency of fertilizer application is increased when

fertigation is used monthly, weekly or continuously, especially if drip irrigation

is used. Foliar application is also used.

Numerous forms of fertilizers have been tested. If the di erent forms

meet the management strategy and crop needs and do not lead to excessive

runo or leaching, most are suitable. The most common forms of nitrogen

are ammonium nitrate (NH

), ammonium sulfate (NH

)

and urea; it

should be applied three to six times per year. For phosphorus, simple or triple

superphosphate is usually applied once a year due to slow P mobility, at rates

of 40–60 kg of P

/ha/year, while, for potassium, potassium chloride (KCl),

potassium sulfate (K

) and potassium nitrate (KNO

) are used, the sulfate

206 Chapter 8

Table 8.4. The quantity of nutrients in banana and plantain with yields of 50 t/ha or 30 t/ha, respectively, from 2400 plants/ha and

bunch masses of 25 kg and 15 kg (Lahav and Turner, 1983), and critical nutrient concentrations in the lamina of the third-youngest leaf

of the vegetative plants (Stover and Simmonds, 1987).

Nutrient Fresh fruit (kg/ha) Remaining in plant (kg/ha)

Proportion removed in

fruit (%)

Leaf lamina critical

concentration in

bananaBanana Plantain Banana Plantain Banana Plantain

N 189 76 199 189 49 29 2.4%

P 29 11 23 16 56 41 0.15%

K 778 243 660 945 54 20 3–3.5%

Ca 101 9 126 149 45 6 0.45%

Mg 49 11 76 53 39 17 0.2–0.22%

S 23 9 50 19 32 32 n/a

Mn 0.5 0.2 12 7 4 3 60–70 ppm

Fe 0.9 0.4 5 3 15 11 60–70 ppm

N, nitrogen; P, phosphorus; K, potassium; Ca, calcium; Mg, magnesium; S, sulfur; Mn, manganese; Fe, iron; n/a, not available.

Banana and Plantain 207

form adds sulfur to the soil, the rates vary widely. For example, using KNO

100 kg/ha in South Africa is suitable where minimum leaching occurs, while

250 kg/ha is needed in Israel and up to 600 kg/ha is used in other countries

with high runo , leaching and yields. Under less-intensive cultivation,

organic matter plus 0.25 kg each of urea and KCl per mat (production unit)

supplement is applied every 3 months. In some areas, no K is recommended,

e.g. the Sula Valley of Honduras and the Jordan Valley of Israel.

If some calcium or magnesium deﬁ ciency is observed, dolomitic rock,

or magnesium sulfate, calcium carbonate or magnesium oxide can be used.

For sulfur deﬁ ciency normally a sulfate fertilizer will solve the problem. For

minor elements foliar application is preferably to soil applications of the

deﬁ cient element.

In the high-density annual planting being used in some places in Latin

America for plantains, if no drip irrigation is in place, research has shown that

two dry fertilizations of N and K per cycle are enough, with 30–40% of the

total yearly amount applied when the plants have developed the ﬁ rst leaf in the

ﬁ eld, and the other 60–70% when they have developed ten leaves; applications

are applied around the single pseudostem (Belalcazar, 1991). Phosphorus is

applied at planting time.

Fig. 8.6. The effect of cutting height of pseudostem at primary bunch harvest on the

growth rate of the follower plant in the month after cutting, crop cycle in months

to harvest of the follower, and the weight of the follower bunch (after Daniells and

O’Farrell, 1987).

208 Chapter 8

Bunch covers

Polyethylene bunch covers (30–40 μm thick) are almost universally used

to improve yield and maintain fruit quality (Fig. 8.7). Some covers have a

pesticide impregnated into them to reduce thrips or mite damage. The covers

produce a warmer microclimate around the bunch, which can accelerate

fruit development; they also prevent ﬁ ngers inside the bunch covers from

being chafed by leaves and covered by dust and pesticides; the cover can also

discourage some insects from entering. The higher temperature and humidity

generated inside the bunch cover are helpful in subtropical areas, though

not required. For tropical areas, perforated covers are used for aeration and

cooling. Covers are applied after the bracts have fallen and should hang 15 cm

below the distal hand. Thinner covers are used in the tropics, where wind is

less of a problem. The banana exporting companies are also using protective

pads between developing hands, so that no bruising or chaﬁ ng occurs

to the fruit.

Fig. 8.7. Bunch covers provide protection of developing fruit from pathogens and

insect damage. The coloured plastic hanging from the bottom of the bunch indicates

date of emergence and is used to indicate harvesting (a). Cableways are used in

large plantations to transport bunches of fruit to the packing sheds to minimize

mechanical injury during handling (b).

Banana and Plantain 209

Disease and pest management

Diseases

Fruit diseases can cause severe problems if not controlled (Table 8.5). The

most virulent disease of banana and plantain is black Sigatoka, which is

found worldwide, except for subtropical areas or tropical areas where it does

not rain and in the Caribbean. Sigatoka disease has two forms: the yellow,

caused by Mycosphaerella musicola and this form is more prevalent in cooler

areas, and black Sigatoka or black leaf streak, which is a much more virulent

type caused by Mycosphaerella ﬁ jiensis. Both alter the photosynthesizing

capacity of the leaf because they produce necrosis that can extend to the

whole leaf area, and at the same time there is an induction for premature

ripening of the fruit because of more ethylene being released by the infected

leaves, thus reducing calipers and yields. Control in intensive production

systems relies on the use of fungicides, which have to be rotated and are

very expensive, increasing the production costs signiﬁ cantly. Therefore, this

approach may not provide a long-term solution for small growers and others

serving local markets.

One way to reduce fungicide costs, which in intensive production systems

can account for 25–30% of the production costs, is to use disease forecasting,

which is based on the evaluation of climatic conditions and calculating

the stage of evolution of the disease (SED). The idea is to spray as soon as it

is considered necessary with a strong systemic fungicide mixed with pure

mineral oil and rotate products with di erent modes of action to reduce

fungicide resistance development. This approach has reduced the 40–60

applications per year to 12–14. Biofungicides have been tried, but in high

disease pressure areas they do not work well, but they can be combined with

contact fungicides, allowing reduction of the rates that are presently used.

Eliminating the necrotic leaves or parts of the leaf is another practice to reduce

dispersion of conidia and ascospores. Breeding for resistance is essential, using

natural resistance in other banana varieties, or biotechnology to transfer

resistance will probably provide a long-term solution.

Fusarium wilt (Panama disease) has caused severe disruption of banana

and plantain production where susceptible cultivars, such as ‘Gros Michel’,

are grown; fortunately, resistant genotypes do exist, but the fungus can

also mutate and eventually a ect them. The two other major diseases are

the bacterial disease ‘Moko’ and the viral bunchy-top disease. For ‘Moko’

prevention is the best strategy, consisting of isolating and eradicating any

infected plant and its neighbours and having tools used for cutting in the

plant, especially the machetes used for desuckering, disinfected after each cut

with Vanodine™ or a similar product.

Preharvest diseases, including fruit freckle (Phyllostictina musarum) and

speckle (Deightoniella torulosa), can cause fruit skin spotting. ‘Cigar-end rot’ is

associated with Verticillium theobromae and Trachyspharea frutigena, infecting

210 Chapter 8

Table 8.5. Principal diseases of banana, causal organisms, distribution, varietal susceptibility and symptoms.

Disease Causal organism Distribution Varietal susceptibility Symptoms

Bacterial

Moko

Pseudomonas

solanacearum:

only distinct

strains of race 2

attack bananas

and plantains

Central and South

America, southern

Caribbean, Philippines,

Indonesia

Cavendish AAA

susceptible, Bluggoe

ABB susceptible, Horn

AAB resistant, Pelipita

ABB resistant

Root: progressive transient yellowing,

older leaves ﬁ rst, necrosis and collapse

of base petiole, younger leaf panels

ﬂ accid and necrotic, premature bunch

development, discolored vascular

bundles cream to brown or black

in all parts of corm, roots, suckers.

Fruit: male bud blackens and shrivels,

vascular discoloration extends up fruit,

bunches blacken and rot and then it

progresses down pseudostem

Blood disease Possibly related to

Moko

Indonesia Bluggoe ABB susceptible Similar symptoms to Moko leaf yellowing

but more conspicuous, reddish tinge

to discolored vascular bundles, infects

fruit via style

Rhizome rot

Erwinia

chrysanthemi

Worldwide Certain AAA and AA

varieties susceptible

incl. Cavendish

Rotting of corms, plant falls over. Soft,

pale brown or yellow rot in outer

cortical tissue. Entry through wounds,

especially in wet conditions

Fungal

Panama disease

(Fusarium wilt)

Fusarium

oxysporum fsp.

cubense

Race :1 worldwide,

Race 2: widely

distributed, Race 3:

Central America,

Race 4: Canary Islands,

Taiwan, Australia,

South Africa

Gros Michel, some

Cavendish varieties

and some plantains

Progressive yellowing from the oldest

leaves, longitudinal splitting lower

portion of the outer leaf sheaths,

wilting and buckling of leaves at the

petiole base. Initial site of infection

feeder roots. Sometimes confused with

Moko disease

Banana and Plantain 211

Disease Causal organism Distribution Varietal susceptibility Symptoms

Sigatoka leaf spots

Black Sigatoka –

Black leaf streak

Mycosphaerella

fijiensis

Paracercospora

fijiensis

Worldwide, except

some islands in the

Caribbean and

subtropical areas

Cavendish and most

other commercial

varieties are susceptible.

Some resistance in

M. acuminata and AA

diploids

Dark leaf spots on lower leaf surface,

which enlarge and coalesce, causes

signiﬁ cant reduction in leaf area and

yield, and premature fruit ripening

Yellow Sigatoka

Mycosphaerella

musicola

Worldwide, more

common higher

elevations cooler areas

Less serious than black

Sigotoka, plantains

(AAB) resistant.

Starts as pale yellow streaks on the upper

leaf surface, they enlarge and coalesce

Viral

Banana bunchy-

top virus

(BBTV)

Vector banana

aphid

South-east Asia,

Australia, India,

Central Africa, Paciﬁ c

Gros Michel AAA

susceptible, Cavendish

AAA susceptible, Saba

BBB tolerant

Infected leaves become stunted and

chlorotic at the margins. Bunching of

leaves at the apex. No fruit production,

suckers infected

Banana mosaic Cucumber mosaic

virus. Many aphids

as vectors

Worldwide Cavendish AAA

susceptible, Horn AAB

susceptible

Sharply deﬁ ned interveinal chlorosis of

leaves can lead to rotting heart leaf and

cylinder. Stunted plants

Banana streak

virus (BSV)

Vector mealy bugs,

infected planting

material

Worldwide Cavendish AAA

susceptible, Mysore

AAB susceptible

Yellow streaks, continuous or broken,

running across the leaf blade. More

pronounced in warm weather

212 Chapter 8

the ﬂ ower perianth and slowly developing along with fruit growth. The end of

the fruit darkens and later is covered with spores looking like a lit cigar. The

disease is found in Latin America, West Africa, Egypt and Australia. The pulp

develops as a dry rot. Removal of pistil and perianth 8–12 days after bunch

emergence and polyethylene bunch covers help to reduce incidence.

A complex of di erent organisms is known to cause the most serious

worldwide postharvest disease – crown rot. The wound caused when the

bunch is dehanded is colonized by the organisms, the rot spreading into the

pedicels during shipping and sometimes into the pulp. A number of organisms

have been found, with the actual complex varying with region; most common

isolates have been Colletotrichum musae, Fusarium spp., V. theobromae, B.

theobromae and Ceratocystis paradoxa. Spores are carried by wind or rain splash;

however, dehanding knives and delatexing tanks may be bigger sources. Good

dehanding practices, with clean cuts using sharp knives, and sanitation of

packing sheds and areas are essential. Exporters use alum and a fungicide to

try to control this infection.

Anthracnose on the fruit skin and neck rot are both caused by C. musae

and can be a serious problem when the fruit becomes overripe. Sanitation and

postharvest fungicide are used for control.

Insect pests and nematodes

Insect pests are generally of minor importance (Table 8.6). Occasionally,

severe fruit scarring can occur. Borers are a problem where control practices,

such as planting clean material and insecticide schedules, are not followed.

The continuous nature of banana production makes pests such as nematodes

more important (Table 8.6).

The main insect problem in many areas of the world is the black weevil

(Cosmopolites sordidus). The weevil lays eggs in the corm, and the larvae

coming from them bore into the corm, causing extensive corm rotting because

of secondary infection. The damage to the roots and the expansion of the

rotting to most of the corm leads to weakening of the plant, which lowers

production, and frequently toppling of the plant with total loss of the bunch.

The main control measures should be paring and disinfecting the corms

before planting, eliminating residues of old plants before a new planting,

fallows and the use of traps with pheromone or pseudostem piece traps; both

attract the adults. In the pheromone traps, the weevils are drowned and in the

pseudostem piece traps they can just be hand-collected or can be poisoned if

an insecticide is added to the piece.

Nematodes can severely limit production, with the extent of the problem

varying with cultivar, soil conditions, type of nematode and plant vigour.

Nematicides are used for fruit destined for export and are applied every 4–6

months, but they are expensive, their use has to be continued and many of

them are being banned by the importing countries. More economic measures

include: improved fallow to eliminate old material, done in combination with

Banana and Plantain 213

Table 8.6. Major pests of banana.

Pest Latin name Spread Susceptibility Symptoms

Banana borer/

weevil

Cosmopolites

sordidus

Worldwide No clones resistant Burrows into rhizome, network

of tunnels, lays eggs at base of

pseudostem, adults (12 mm long) feed

on pseudostem, nocturnal

Bunch pests

Thrips

Chaetanaphothrips

spp. red rust thrip

Central America, South

America, Asia, Australia

Rust blemish to fruit skin, especially

between ﬁ ngers of immature fruit

Frankliniella spp.

South-east Asia, Australia, Corky scab on developing fruit

Flower thrips Caribbean, Latin America

Scab moth

Nacoleia octasuma

Australia, Paciﬁ c Islands Brown scabs on developing fruit

Nematodes

Burrowing

nematode

Radopholus similis

Most areas except East

Africa, Israel, Canary

Islands, Egypt and

Taiwan

AAA more tolerant

than AAB

Elongated blade, lesions on root

Lesion nematode

Pratylenchus

goodleyi

African highlands, Canary

Islands

Cavendish

susceptible

Similar to R. similis

Pratylenchus

coffeae

Tropics AAB more commonly

associated

Root-knot

nematodes

Meloidogyne spp.

Worldwide Deformation and stunting of roots. Gall

formation

214 Chapter 8

an injection of herbicide into the pseudostems, resulting in the nematode

population being signiﬁ cantly reduced; use of water isolation ditches so no

nematodes enter the ﬁ eld through water coming from neighbouring ﬁ elds;

use of healthy plant material – initially it could be tissue-cultured although

it is very expensive; use of tolerant or, hopefully in the near future, resistant

varieties and the reintroduction of biodiversity with new and di erent green

manure or cover crops, manure incorporation and other practices (Rísede et

al., 2010).

Weed management

Weeds are a major problem during stand establishment before canopy closure

occurs. Cultivation needs to be carefully carried out so as not to damage the

surface feeder roots, using hand-hoeing around the plants. Herbicides can

be used once the banana canopy is su ciently high to avoid contact with the

leaves. Mulching and intercropping during early stand development can be

used. Failure to weed can lead to severe yield decline. It is very important to

keep the area around the new plants clean during the initial weeks until they

develop and then continue to clean until the shade of the canopies will reduce

the weed problem.

Orchard protection – windbreaks

Banana plants tolerate wind up to 30 m/s. Higher speeds lead to tearing of leaf

laminas. Windbreaks may be necessary if prevailing winds tear leaves into

strips less than 5 cm wide (Turner, 1994). The need for a windbreak must be

balanced against the e ects of shading, the area needed, competition for water

and nutrients, and the limited protection on the leeward side. Plant propping is

carried out to reduce the impact of winds or the excessive weight of the bunch.

HARVESTING AND POSTHARVEST HANDLING

Harvesting

Individual ﬁ ngers increase in weight and begin to lose angularity in cross

section during maturation. Fruits for export are harvested while still green

at 75% maturity with some angularity, 10–14 weeks after ﬂ ower emergence

in the tropics and up to 9 months in the cool subtropical areas. The idea is to

export only fruit that is not over-aged and that has a minimum caliper. The age

of the fruit is established by tying a coloured ribbon to the bunch cover at the

time the cover is put in place, so the di erent ribbon colours indicate the week

Banana and Plantain 215

the bunch emerged. The maturity is checked by determining the caliper of the

middle ﬁ nger of the outer whorl of the second hand. When the caliper reading

is between 31 and 41 mm in diameter, the bunch is ready to harvest. If the

caliper reading is less than the 31–41 mm minimum, the ﬁ nger is rechecked

the next week, and if after the week the caliper is still too small, the bunch

will be harvested and fruit sent to the local market. In this way, over-aged

fruit are not exported. If over-aged fruit are included in export fruit shipment,

it is possible that they will start to ripen in transit and induce ripening of the

whole shipment.

Small growers tend to harvest bunches when more than three-quarters

mature with little angularity and at fully rounded stage. More mature fruit

have a shorter postharvest life and are more liable to be sunburnt and split.

Other criteria used to judge maturity include drying of leaves, drying of stylar

ends and days from bunch emergence. The days from bunch emergence can

vary from 7 to 24 weeks, depending upon cultivar, season, crop management

and environment. Other measures include pulp to peel ratio and skin ﬁ rmness.

The bunch is removed from the plant by cutting a notch in the pseudostem

while supporting the bunch with a pole and slowly lowering it on to the

shoulder pad of a harvester. The stem is then fully cut, leaving a 300 mm

peduncle. The bunches are transported to the packing shed on padded trailers

or on an overhead cable system. Dehanding can be performed in the ﬁ eld, with

the hands transported to the packing shed on padded trailers. Care is essential

in these steps to avoid any mechanical injury that would reduce fruit quality.

Plantains in the tropics are harvested for export about 11 weeks after

ﬂ ower emergence, and colour ribbons are again used as a guide to establish

bunch age. Plantain maturity standards vary widely and lead to considerable

variation in product quality.

Postharvest treatments

Bunch covers are removed in the ﬁ eld or after the bunches reach the covered

packing shed. Bunches must be protected from exposure to direct sunlight to

avoid sunburn injury during transportation and at the packing-shed holding

area. Hands are removed with a sharp, curved knife or curved chisel, leaving

part of the crown attached. The hands, irrespective of whether dehanding

takes place in the ﬁ eld or in the packing shed, are placed in clean water to

remove dirt and latex exuding from the cut crown; this should last a minimum

of 20 min. Care is needed to avoid the build-up of fungal spores in the water of

the wash tank, by frequent changes and the use of chlorine.

The hands are removed from the tank and sometimes cut into clusters of

adjacent ﬁ ngers, with defective ﬁ ngers being removed. The clusters are placed

in trays that pass through a fungicide-treatment spray or dip on a conveyor.

The conveyor then passes the trays to a packing station, where weight

216 Chapter 8

adjustment occurs and the fruits are packed into cardboard cartons, with a

thin plastic liner to prevent chaﬁ ng injury and water loss. Hands or clusters

are tightly packed to avoid movement during shipping. Carton sizes vary

from 12 to 20 kg, with Central American cartons holding 18.1 kg of fruit.

Cartons may then be cooled to 13°C before shipping to market. In small local

operations, bunches may be sold, with dehanding taking place upon sale to

the consumer. Alternatively, hands may be shipped to market in a number of

di erent containers. Export dessert bananas, because of the regular nature of

the hands and curved nature of the ﬁ ngers, can be easily packed. Many other

cultivars are not as easily packed, as the ﬁ ngers are not arranged in a regular

manner, e.g. ‘Pisang Mas’ (AA).

Green bananas are shipped at 13–14°C to delay ripening. Lower

temperature can lead to chilling injury, whose symptoms include a dull, grey

skin colour, poor ripening, poor conversion of starch to sugar, poor ﬂ avour

development and susceptibility to decay. Symptom development is dependent

upon exposure temperature and time, and susceptibility depends mostly on

the cultivar. Maturity, prior growing conditions and previous temperature

exposure may also be factors. ‘Dwarf Cavendish’ shows injury after 20 days at

11°C and ‘Lacatan’ after 12 days at 14°C. Plantains, such as ‘Pisang Awak’,

are less susceptible to chilling injury than dessert types.

Marketing

Market quality standards vary widely, with export bananas having the most

stringent standards. In large measure, this is related to consumer preferences

and the condition of the bananas received at the market. In western

supermarkets, unblemished fruits are preferred, even required, while in

markets in tropical areas postharvest handling is very abusive and fruits with

blemishes are normal, with degree of fruit ripeness being a deciding factor.

Export quality standards are applied before and after shipping and

include: blemishes and fruit shape, ﬁ nger length and diameter, cluster size

and arrangement, and carton weight. A minimum ﬁ nger length on a hand is

203 mm for export from Central to South America, with the whole hand being

culled if one ﬁ nger does not meet this standard. When hands are cut into

clusters, the cull ﬁ ngers are carefully cut out. The diameter for ‘Cavendish’

ﬁ ngers ranges from 31 to 41 mm. Fingers with obvious blemishes are culled.

Such standards can lead to cull rates of up to one-third, with culled fruit being

sold locally, processed or dumped.

Banana fruits are very susceptible to both abrasion and impact injury.

The major marketing problem of export bananas is mechanical injury,

which shows itself as black sunken areas on the skin after ripening. The

thin plastic liner in export cartons minimizes chaﬁ ng damage to ﬁ ngers that

rub against the side of the carton during handling. Latex allowed to dry on

Banana and Plantain 217

the skin oxidizes as brown and black stains and can lead to downgrading

of fruit. Other concerns are diseases, particularly crown rot, which may

a ect the whole carton and promote uneven fruit ripening. Because of weak

pedicels, the ﬁ ngers of some cultivars fall from the hand during ripening,

exposing the pulp.

Plantains have a tougher skin than bananas and so there is less danger

of causing harm to them by improper handling; in general they should be

treated the same way as bananas, but in most instances they use less elaborate

systems for harvest, transport to the packing house and packing than for

bananas.

Plantain boxes weigh 22.6 kg. Alternatively, green plantains are partially

ripened, peeled and frozen, with a heat treatment to minimize enzymatic

browning reactions.

Ripening

Dessert bananas are allowed to ripen and are chieﬂ y eaten raw when they

have low starch, high sugar and developed ﬂ avour. Plantains have high starch

content and are eaten when green or ripe after boiling, frying or roasting. The

conversion of starch to sugar during ripening of plantain-type bananas is less

complete than in dessert bananas (Fig. 8.8).

The ripening process for the export dessert-type bananas is normally

carried out by specialists under controlled conditions just before distribution

and marketing to consumers. When bananas are allowed to ripen naturally,

it is di cult to predict when fruit will be ready to eat. Under controlled

ripening conditions, ethylene is supplied from compressed gas cylinders,

ethylene generators or ethylene-generating chemicals, such as ethephon.

Commercially, bananas are treated with about 100 ppm ethylene for about

24 h under controlled temperature and humidity conditions and ventilation

to prevent carbon dioxide (CO

) build-up. Newer systems pressurize the

room to allow uniform ethylene distribution and temperature. Temperature

control allows fruit to be ripened on a speciﬁ c schedule to colour stage 3 for

distribution in from 4 days at 19°C to 10 days at 14.5°C. The humidity control

has a signiﬁ cant impact on the ﬁ nal skin colour developed and ﬂ esh softening.

In local markets, fruits are ripened by covering with a tarpaulin or cloth

after inserting a packet of calcium carbide (0.3 g/l) to generate acetylene.

Acetylene is a 100 times less e ective analogue of ethylene. A proliﬁ c ethylene-

producing ripening fruit, such as avocado, can also be used as an ethylene

source, as can burning of incense sticks or young leaves of a number of trees,

such as gliricidia (Gliricidia sepium Stend) (Acedo and Bautista, 1991).

218 Chapter 8

UTILIZATION

The main carbohydrate di erence between bananas and plantains is that

bananas are less starchy than plantains (Fig. 8.8). Bananas had 1% starch

when fully ripe and 0% when overripe, while plantains had 9% starch when

fully ripe and 3% when overripe (Marriot el al., 1981). The same bananas

had 23% sugar when ripe or overripe while plantains had 20% sugar when

ripe and 27% when overripe. The moisture content of ripe bananas is ~80%,

versus ~65% for plantains. Bananas are at their best when yellow, plantain

when black.

The ﬂ avour, texture, convenience, ease of eating and nutritional values

have made dessert bananas very popular (Baldry et al., 1981). Banana is a

useful source of vitamins A, C and B6 and has about twice the concentration

of K compared with other ripe fruit (Table 8.7). Plantain as a staple provides

considerable energy and protein, although the diet needs to be supplemented.

In West and Central Africa, people derive about one-quarter of their energy

requirements from plantains (Wainwright, 1992).

Bananas are used in special diets where ease of digestibility, low fat, no

cholesterol, minerals (high K, low sodium (Na)) and vitamin contents are

Fig. 8.8. Change in dessert bananas’ and plantains’ colour score (a), and starch and

total sugars (b) (redrawn from Marriot et al., 1981).

Banana and Plantain 219

required. The fruit does not cause digestive disturbance; it readily neutralizes

free acid in the stomach and does not give rise to uric acid. These special

diets are used for babies, the elderly and patients with stomach problems,

gout and arthritis.

Only a very minor proportion of the total world banana production is

processed. The procedures used include canning as slices, drying as slices or

ﬂ akes, freezing of juice, extraction, frying and fermentation. Puree is canned

or frozen and used in baby foods, baking and drinks. Banana essence is a clear

colourless liquid used in desserts, juices and drinks. Dried ripe fruit can be

made into ﬂ our. The lack of acidity makes processing di cult, because of the

need for pasteurization. A year-round supply of fresh fruit makes preservation

less economic. A beer is brewed from plantains, also called beer bananas, and

consumed in Uganda and Tanzania.

Plantains can be eaten green or ripe. Green plantains can be peeled and

cooked or cooked and mashed and mixed with bacon or pork meat pieces or

boiled and mashed and made into balls that are eaten in soups. The green

Table 8.7. Proximate fruit composition of banana and plantain in 100 g edible

portion (Wenkam, 1990). Differences in mineral content can be due to cultivar,

fertilization, water supply and environment.

Williams (AAA) Brazilian (AAB) Plantain (BB)

Water (g) 71.3 79.2 64.1

Energy (kJ) 418 301 523

Protein (g) 1.08 1.75 1.28

Lipid (g) 0.13 0.18 0.03

Carbohydrate (g) 26.56 18.03 33.39

Fibre (g) 0.11 0.25 0.43

Ash (g) 0.9 0.82 0.87

Minerals

Calcium (mg) 5 2 4

Iron (mg) 0.49 0.35 0.54

Magnesium (mg) 40 26 35

Phosphorus (mg) 18 13 21

Potassium (mg) 494 302 393

Sodium (mg) 1 1 3

Vitamins

Ascorbic acid (mg) 5.1 8 17.5

Thiamine (mg) 0.044 0.026 0.038

Riboﬂ avin (mg) 0.045 0.041 0.064

Niacin (mg) 0.69 0.61 0.43

Vitamin A (IU) 88 82 31

220 Chapter 8

fruit can also be cut into round or long slices that are deep fried and eaten as a

snack. In some cases, thick slices about 10 mm wide are cut, partially fried and

then expanded by pounding them, after which the frying is completed; these

slices, called ‘patacones’ or ‘tostones’, are very popular in Latin America and

are eaten as a side order with meat and other food preparations. Plantains are

also left to ripen completely until their peel turns black, at this point they are

usually sweet (Fig. 8.8); after this they are peeled and sliced or halved and fried

or baked to be eaten with the main course. Alternatively, the ripe fruits are

baked as a very nice dessert with added sugar, cream or butter, and cinnamon.

Corms, shoots and male buds are also eaten as a starch source or

vegetable. Immediately after harvest, the pseudostem still has considerable

starch reserves. The male bud, with the outer ﬁ brous bracts removed, is boiled

in South-east Asia and eaten as a vegetable, after several changes of water to

remove astringency. Banana leaves are used as food wrappers for steaming.

FURTHER READING

Gowen, S. (ed.) (1995) Bananas and Plantains. Chapman and Hall, London.

Hassan. A. and Pantastico, F.B. (eds) (1990) Banana – Fruit Development, Postharvest

Physiology, Handling and Marketing in ASEAN. ASEAN Food Handling Bureau,

Kuala Lumpur, Malaysia.

Robinson, J.C. (1996) Bananas and Plantains. Crop Production Science in Horticulture,

CAB International, Wallingford, UK.

Simmonds, N.W. (1982) Bananas, 2nd edition. Tropical Agricultural Series, Longman,

London.

Soto, M.S. (1992) Bananos (in Spanish). Lithography Imprenta LIL, San José, Costa

Rica.

Turner, D.W. (1994) Bananas and plantains. In: Scha er, B. and Andersen, P.C. (eds)

Handbook of Environmental Physiology of Fruit Crops. Vol. II, Subtropical and Tropical

Crops. CRC Press, Boca Raton, Florida, pp. 37–64.

Turner, D.W. (1997) Bananas and plantains. In: Mitra, S.K. (ed.) Postharvest Physiology

and Storage of Tropical and Subtropical Fruits. CAB International, Wallingford. UK,

pp. 47–83.

(R.E. Paull and O. Duarte)

LITCHI AND LONGAN

Litchi (Litchi chinensis Sonn.) and longan (Dimocarpus longan (Lour.) Steud) are

members of the Sapindaceae. These sub-tropical and tropical trees, respectively,

are grown widely in the tropics. The fruit is marketed fresh, dried, canned and

as juice.

BOTANY

The Sapindaceae is composed of around 150 genera and 2000 species of trees,

shrubs, and a few herbs and vines, usually monoecious, distributed widely in

the warm tropics and subtropics. The common family name soapberry refers

to the tree (Sapindus saponaria L.), a native of tropical America producing a

fruit containing a soap-like substance (37% saponin). The majority of species

are native to Asia, with a few species in South America, Africa and Australia.

Among the numerous genera, four related genera and ﬁ ve species are of

interest to the fruit horticulturist:

1. Blighia sapida Koenig, the Jamaican akee, is native to Guinea and is com-

monly grown in the Caribbean Islands, particularly in Jamaica. The brightly

coloured yellow to red fruit has thick walls in three parts, each containing a

white nut-ﬂ avoured pulp with a shiny black seed attached at the tip. Pulp from

immature or overripe fruit and the pink raphe attaching the aril to the seed are

poisonous. When the pods open naturally, the pulp can be fried or boiled. When

fried, it resembles scrambled eggs.

2. Dimocarpus longan (Lour.) Steud., longan, lungan, langngan, dragon eye

(English), lengkeng (Malaysia, Indonesia), longanier, oeil de dragon (French),

lamyai pa (Thailand), or nhan (Vietnam) is reported to have originated

in north-eastern India, Burma or southern China in the Yunan province.

Commonly called dragon eye, the trees attain heights of 9–12 m under suitable

environments and it is more vigorous than the litchi (Menzel et al., 1988b).

The longan is generally grown in similar areas to that of litchi in China and

Thailand but climatic requirements are less exacting.

222 Chapter 9

3. Litchi chinensis Sonn., ssp. chinensis, the litchi, is a subtropical species

indigenous to south China. It is principally cultivated in Guangdong, Fujian,

Guangxi and Sichuan provinces. Gro (1921) discusses in detail the origin of

the names litchi and longan. The Chinese characters for litchi convey the idea

that the fruit of the litchi must be removed from the tree by means of knives

with the twigs attached. Many cultivar names are pronunciations of various

southern Chinese dialects and spellings, which has led to some confusion. The

most recent Chinese descriptions use the spelling litchi and national dialect

name (Mandarin – common language). Other spellings and common names

are lichee, litchee, leechee, lychee, lin-chi (Thailand), laici (Malaysia), lici, litsi

(Indonesia), letsias (Philippines), li-chi or lizhi (China), vai, cayvai, or tu hu

(Vietnam).

There are two subspecies; one is found in the Philippines (ssp.

philippinensis) and the other in Indonesia (ssp. javanensis). The Philippine

subspecies has a long, oval-shaped fruit with thorn-like protuberances

that split when ripe, exposing an inedible aril, partially covering the seed.

The Indonesian subspecies is similar to the Chinese species and crops

more regularly in hot equatorial areas, though it has not been exploited

commercially.

4. Nephelium lappaceum L., the rambutan (Indonesia, Malaysia, Philippines,

English), litchi chevelu (French), and ngoh and phruan (Thailand), and

Nephelium ramboutan-ake Bl., the pulasan, ngo-khonsan (Thailand) and

kapalasan (Indonesia) are both native to the Malaysian peninsula and are now

distributed widely in South-east Asia. This species will be covered in Volume 2.

ORIGIN AND DISTRIBUTION

The cultivation of litchi in China antedates the beginning of the Christian era

according to Chinese writings going back to 1766  (Storey, 1973). Early

distribution into other tropical and subtropical regions occurred during the

16th and 17th centuries. The litchi was introduced into India in 1798 and has

developed into a signiﬁ cant industry. Litchi and longan reached Europe during

the early part of the 19th century and are mentioned as having reached

Trinidad before 1880, with a few trees being grown in Florida as early as 1883

(Gro , 1921). The ﬁ rst litchi tree is said to have been brought to Hawaii about

the year 1873 by Mr Ching Chock, a Chinese merchant, and was planted

on the property of Mr Chun Afong and became known as the ‘Afong’ tree,

identiﬁ ed as Gui Wei (Kwai Mi), later re-identiﬁ ed as similar to ‘Da Zao’. The

o ce of Foreign Seed and Plant Introduction in the United States, Department

of Agriculture began introducing litchi plants in 1907. The late Professor

G.W. Gro , who resided in south China almost continuously from l907 to l94l

as Dean of the College of Agriculture, Lingnan University, Guangzhou, China,

was responsible for the introduction of a large number of cultivars into the

Litchi and Longan 223

USA. His contributions number 17 out of the 25 cultivars and clones now

established in Hawaii. Today, the litchi is found in most countries of Latin

America, the Caribbean, India, Mauritius, Africa, Australia, Israel, the Canary

Islands, Madeira Islands, and many other countries.

ECOLOGY

The litchi and longan are evergreen subtropical plants, indigenous to areas

where cool, dry winters and warm, wet and humid summers prevail. Such

conditions are found mostly in subtropical regions and at higher elevations

in the tropics. In Guangzhou, summers are known for their rains and high

humidity (>80%) during night and day. The winter is cool and dry, and frost is

rare. Litchi is described as a water-loving, low-elevation plant, which is planted

largely along the banks and dykes in the Pearl River delta in Guangdong.

However, there are upland cultivars (mountain litchi) grown on hillsides or in

orchard systems with very little tillage after the trees mature.

Soil

Observations indicate that the litchi and longan thrive on a wide variety of soil

types as long as drainage is good enough to prevent waterlogging. Satisfactory

litchi growth occurs in India and Florida in neutral to slightly alkaline soils,

with free lime present. In south China, the litchi soils are alluvial silty loams

to clays in the Pearl River delta or laterite soils on the hills. Longan thrives best

on deep clay loams, and both species prefer a slightly acid (pH 5.0–6.5) soil.

Climate

Rainfall and moisture

High rainfall and humidity induce good growth in litchi and longan, with

litchi being able to resist ﬂ oods. Roots of litchi trees covered with water for 8

days showed no deleterious e ects, even when fruiting. In China and Thailand,

litchis are also grown on banks with high water tables beneath them.

Ample annual rainfall is considered to be around 1250–2000 mm for

litchi and 1500–3000 mm for longan. When rainfall is lower, irrigation is

essential. A dry autumn and winter is important to prevent litchi vegetative

growth (Fig. 9.1), which is essential to good ﬂ owering (Nakata and Watanabe,

1966). In south China, litchi anthesis occurs during the rainy season

(130–375 mm/month) and when relative humidity is higher than 80%. Too

much rain during anthesis, however, can reduce ﬂ ower opening and insect

activities needed for pollination. A major problem of litchi culture in Hawaii,

with the exception of the Kona district of Hawaii, is that rainfall comes in

late autumn and winter, making it di cult to control vegetative ﬂ ushing.

Irrigation after a period of soil water stress is reported to aid in longan

224 Chapter 9

ﬂ owering (Fig. 9.1), even though the tree ﬂ owers profusely in areas with high

water tables. Both crops require adequate moisture, from rainfall or irrigation,

during fruit set and growth.

Temperature

Young litchi and longan trees are severely damaged or even killed at −2

to −3°C, with dormant and mature trees having more tolerance to low

temperatures. Periodic cold is required for ﬂ owering, though in Guangzhou,

air temperatures rarely drop below 0°C. The total duration of relatively low

temperatures rather than the frequency or time of occurrence during a critical

period seems to be the determining factor (Fig. 9.1). When trees are deeply

rooted, low air temperature is more important than soil moisture (Menzel et

al., 1989). There is considerable cultivar di erence in response to temperature

(Menzel et al., 1989). In a test involving seven cultivars, all cultivars showed

panicle emergence after 6 weeks at 15/10°C or at 20/15°C; however, there

are di erences in the degrees of ﬂ owering between the cultivars at 20/15°C

(Table 9.1). There is no ﬂ owering at 25/20°C or 30/25°C. Temperature also

inﬂ uences the time from emergence to anthesis: 14–16 weeks at 20/15°C,

versus 6–8 weeks at 15/10°C. The greatest number of inﬂ orescences

per branch occurs if low temperatures are maintained until anthesis. If

temperatures are increased from varying the period at 15/10°C to 30/25°C

after emergence and before anthesis, there is a reduced number of female

ﬂ owers and some ﬂ oral buds revert to vegetative growth (Fig. 9.2). Pollination

is optimum at about 19–22°C and occurs in 5–7 days. At lower temperatures,

pollen tube growth is strongly inhibited. Hot, dry conditions may reduce

Litchi

Longan

Harvest Leaf Growth Rest

Floral Induction

and development

Temperature >25 °C

High water, high N

Temperature <25 °C

Low water and N

Temperature <25 °C

Low water and N, or sodium chlorate

Temperature >25 °C

High water, high N

Girdling

Remove vegetative shoots

Pruning

old panicle removal

fertilize and Irrigate

Fertilize

Irrigate

Temperature <25 °C

Temperature >15 °C

or <10 weeks

Temperature >22 °C

or <8 weeks

8–10 weeks

Flowering

No flowering

Irrigate

Temperature 15 °C

Temperature 15–22 °C

10 weeks

Infloresence

with flowers

only

Infloresences

with one or more

leaves or revision

to vegetative shoot

Harvest Leaf growth Rest

Floral Induction

and development

Fig. 9.1. Fruiting cycle of litchi (after Menzel and Simpson, 1994) and longan as

affected by temperature, nitrogen fertilization and water availability. Litchi leaf low

nitrogen levels need to be in the range of 1.75–1.8%. There can be more than one

ﬂ ush of leaf growth during the year. Longan can be induced to ﬂ ower with a sodium

chlorate treatment.

Litchi and Longan 225

yields, as poor fruit set occurs at 33°C. In hot equatorial areas, litchi grows

vegetatively and seldom ﬂ owers.

Longan is less demanding than litchi for ﬂ owering, requiring 15–22°C

for 2–3 months for ﬂ ower induction (Fig. 9.1). The exact chilling and cultivar

di erences in this requirement are not known. In hot equatorial areas, longan

grows vegetatively and seldom ﬂ owers. Flowers can be induced by a chemical

treatment discussed below.

Light intensity and photoperiod

Litchi is a day-neutral plant, and ﬂ oral initiation is associated with starch

content of leaves and stems. Shading, such as when litchi trees begin to crowd

each other in an orchard, leads to a decline in production, due to smaller

panicles and a decrease in the number of panicles on a tree (Lin et al., 1991).

Shading to 50% of full sunlight causes a 40% reduction in the panicles formed

and a 65% reduction in panicle length. There is little information on the

response of longan to varying light levels; it is thought to be day neutral.

GENERAL CHARACTERISTICS

Tree

The litchi is a spreading evergreen tree, growing to 10–12 m under favourable

conditions. It is generally considered to be a slow grower with a long life. A

Chinese writer, Wen Hsun Chen, said that at the time of his writing (before

1924), the cultivar ‘Chenzi’ (Chen Family Purple, ‘Brewster’) was already

300 years old and still thriving (Gro , 1921). Depending upon cultivar, trees

may be broad with low-hanging branches or have upright branches and a

compact, rounded head. Branches are brittle and even large limbs are easily

broken by winds.

Table 9.1. Effect of temperature and cultivar on percentage of litchi terminal

branches ﬂ owering. Trees at 25/20°C and 30/25°C did not ﬂ ower (Menzel and

Simpson, 1988). Panicles can be of two types; one has only ﬂ owers, while the other

has a mixture of leaves and ﬂ owers, and is referred to as a leafy panicle.

Cultivar

Vegetative shoot

Branches ﬂ owering %

Leafy panicles Leaﬂ ess panicles Flowering panicles

15/10°C 20/15°C 15/10°C 20/15°C 15/10°C 20/15°C 15/10°C 20/15°C

Da zao 0 50 93 50 7 0 100 50

Bengal 0 49 71 32 29 9 100 41

Shui dong 0 58 39 3 61 28 100 31

Gui wei Pink 0 20 55 69 46 8 100 77

Gui wei Red 0 80 7 3 93 5 100 8

Salathiel 0 17 0 20 100 58 100 78

Huai zhi 0 4 0 14 100 81 100 95

226 Chapter 9

Leaves are arranged alternately, pinnately compound with two to ﬁ ve

pairs of leaﬂ ets arranged in opposite positions or slightly obliquely along the

rachis (Fig. 9.3). The leaﬂ ets are elliptical to lanceolate, 2.5–6.4 cm wide,

7.6–17 cm long, and deep green. Young, emerging ﬂ ushes range from pale

green to pinkish to a copperish red. Growth ﬂ ushes can occur several times a

year and are vegetative ﬂ ushes of several leaves in summer and can be ﬂ oral

in winter. Vegetative ﬂ ushing is encouraged immediately after harvest in

summer by fertilizing and irrigating (Fig. 9.1). The ﬂ oral ﬂ ush is a terminal

inﬂ orescence. A close relationship exists between number of leaves associated

with a ﬂ owering panicle and number of fruits on that panicle (Fig. 9.4). Hence,

a minimum number of two leaves per fruit is required.

The longan tree can grow to 20 m and has either a spreading or erect

habit. The compound longan leaves are around 25 cm long with 6–12 leaﬂ ets,

alternate or nearly opposite, oblong, 5–15 cm long with blunt or pointed

ends (Fig. 9.5). The leaves are dark glossy green on the upper side and pale

green underneath.

Flowers

The small litchi ﬂ owers are 3.0–6.0 mm in length when fully expanded (Fig.

9.3), and borne in profusion on leaﬂ ess or leafy, well-branched terminal

panicles. In the northern hemisphere, appearance of panicles can begin

as early as November to as late as April, depending upon cultivar and

environmental conditions. Flowers are yellow-green or brownish-yellow,

apetalous with small valvate sepals (Fig. 9.3), a ﬂ eshy disc and up to eight

stamens. Among the numerous, apetalous ﬂ owers on the panicle, three sex

types are described for litchi. These sex types are designated Types I, II and III,

Percentage

100

Leafy panicles

Leafless panicles

Vegetative shoots

Days at 15/10°C after panicle emergence

80 120 160

Fig. 9.2. Effect of post-panicle emergence temperature response to 15/10°C before

transfer to 30/25°C on ‘Gui wei’ litchi panicle development (after Menzel and

Simpson, 1991).

Litchi and Longan 227

based on the chronological order of development. Type I is morphologically

and functionally a male (Fig. 9.3), possessing six to eight stamens producing

an abundance of pollen and lacking ovule di erentiation. Type II ﬂ ower is

morphologically a hermaphrodite functioning mostly as female, with a well-

Fig. 9.3. Leaf, ﬂ ower and fruit of Litchi chinensis. (a) male ﬂ ower with reduced pistil

and six stamens, and (b) ‘hermaphrodite’ ﬂ ower, which functions as a female with a

well-developed pistil (two carpels and a bilobed stigma and six to eight stamens that

do not dehisce (sterile)). From Nakasone and Paull (1998).

228 Chapter 9

developed two-carpel pistil and a two-lobed stigma (Fig. 9.3). The ﬁ ve to

eight stamens do not dehisce normally and have little viable pollen. Type III

ﬂ owers function as a male, though they are morphologically a hermaphrodite

with a rudimentary pistil lacking style and stigma. The six to eight stamens

produce numerous viable pollen grains. Approximately two-thirds of the

ﬂ owers on a panicle are composed of Type III and only about 20% of the

ﬂ owers are potentially fruit-producing (Type II). Observations indicate that

the ratio of functional females (Type II) to functionally staminate ﬂ owers

(Types I and III) varies with cultivar (Table 9.2), with 10–30% being female

(Limangkura, 1966). Similar sex types occur in longan (Lian and Chen,

1965), of small, greenish-yellow to brownish, self-incompatible ﬂ owers

having ﬁ ve sepals and ﬁ ve petals (Fig. 9.5). Insects are the major pollinators

(Alexander et al., 1982).

Litchi ﬂ oral anthesis occurs in cycles of sex types (Mustard, 1954), with a

period of about 10 days during which only functional male ﬂ owers are open.

This is followed by a transitional period of 2–3 days when both staminate

and female (Type II) ﬂ owers open, then 2 days of only female ﬂ owers. This is

followed by 2–3 days of transitional types, and ﬁ nally male ﬂ owers for a period

of 7–10 days. The number of days to complete each of the cycles appears

to di er somewhat among inﬂ orescences and between cultivars and with

environmental conditions. Inﬂ orescences produced around the same time

generally produce the same sex types. It has been observed that the initial

ﬂ owers are all functionally male in one season, and in the following season

initial ﬂ owers at one site may be all functionally female and at another site

all functionally male. Thus, the inﬂ orescence may begin ﬂ oral anthesis at any

sexual phase of the cycle, going through the above sequence. The expression

100 leaves per panicle

50 leaves per panicle

2 leaves per panicle

10 20 30

Days from full bloom

Fruits per panicle

40 50 60 70

Fig. 9.4. Effect of leaf number on the litchi panicle branch to number of fruit set per

panicle for cultivar ‘H-1224’ (after Yuan and Huang, 1988).

Litchi and Longan 229

of sex type may be related to temperature, with lower temperatures leading to

a higher percentage of Type II ﬂ owers.

Longan ﬂ owers are small, greenish-yellow to brownish, and self-

compatible with ﬁ ve sepals and ﬁ ve petals. Longan has the same three di erent

ﬂ ower types as in litchi: staminate ﬂ ower (Type I), hermaphrodite ﬂ ower

functionally as ‘female’ (Type II) and hermaphrodite ﬂ ower functionally as

‘male.’ Longan shows a similar progression of ﬂ ower types under normal

conditions: ﬁ rst functionally male, then hermaphrodite and ﬁ nally male.

However, the Type II may bloom ﬁ rst under some cultural management

Fig. 9.5. Leaf, ﬂ ower and fruit of Dimocarpus longan. (a) female ﬂ ower with two

carpels and a bilobed stigma and stamens on short ﬁ laments, which do not dehisce,

and (b) male ﬂ ower showing eight hairy stamens with bilobed anthers (from

Nakasone and Paull 1998).

230 Chapter 9

practices or di erent climatic conditions. An overlap of the types occurs on

one tree since not all panicles open at the same time.

Pollination and fruit set

Natural pollination

Controlled pollination studies have shown the presence of a relatively high

degree of self-sterility in litchi. Limangkura (1966) self-pollinated litchi ﬂ owers

and produced 4.2% set, while cross-pollinated ﬂ owers yielded 6.9% set. Litchi

inﬂ orescences caged to prevent insect visitation had 0.026–0.105% fruit set as

compared to 0.17–11.25% fruit set on inﬂ orescences open to insect visitation

(Pandey and Yadava, 1970). Bees (Apis and Mellifera spp.) make up 98–99%

of the total insect visitors to the ﬂ owers, mostly during the morning hours,

when nectar secretion occurs. The stigmas of litchi ﬂ owers are receptive to

pollination for 72 h from the time it divides into the two lobes, and the anthers

remain functional up to 1–3 days after anthesis.

Controlled pollination studies in longan have shown the presence of a

relatively high degree of self-incompatibility. Bees (Apis and Mellifera spp.) are

the major pollinators and comprised 98–99% of the total insect visitors to

the ﬂ owers. The visits occur mostly during the morning hours, when nectar

secretion occurs. Too much rain during anthesis can reduce ﬂ ower opening

and the insect activity needed for pollination. Irrigation after a period of

soil water stress is reported to aid in ﬂ owering, even though the tree ﬂ owers

profusely in areas with high water tables.

Floral induction, fruit set and chemicals

Growth regulators and other horticultural techniques have been tried by many

researchers to overcome the problem of irregular litchi ﬂ owering, to enhance

fruit set and to reduce seed size (Menzel, 1983; Joubert, 1986). Sodium

naphthalene acetate (SNA) at 200 and 400 ppm promoted blossoming in

‘Chenzi’ only when climatic conditions favoured vegetative growth. The

inhibition of vegetative growth is a requisite for ﬂ oral initiation, and SNA

mimics low temperatures that inhibit growth. There is no increase in ﬂ oral

Table 9.2. Distribution of the three sex types of ﬂ owers per panicle of two litchi

cultivars (Limangkura, 1966).

Cultivar

Flowers per

panicle

Functional ﬂ ower type (%)

Potential fruiting

ﬂ owers (%)I II III

Groff 964 14 20 66 20

Hei ye 1042 22 19 59 19

Litchi and Longan 231

initiation and yields by SNA treatment during years with dry autumn months

and on trees that yielded heavily during the previous season.

A combination of ethephon and kinetin is more e ective in reducing

litchi shoot length and inducing high proportions of ﬂ oral buds than either

chemical alone (Chen and Ku, 1988), while unsprayed shoots remain

vegetative. Killing winter ﬂ ushes by the use of chemicals to promote litchi

ﬂ owering is also practised. A 25% urea solution, ethephon (1500 mg/l),

maleic hydrazide (0.125%) and DNOC (dinitro-orthocresol) at 0.1–0.5% forces

the young winter leaf ﬂ ush to abscise, with subsequent emergence of axillary

ﬂ owering. A 0.5% urea spray applied to the late-summer growth ﬂ ush causes

the soft leaves to turn green, mature quickly and produce ﬂ owers in the spring.

The higher the concentration of ethephon applied at the time when trees

approached ﬂ owering, the lower the percentage of ﬂ owers produced.

Girdling (cincturing) branches or the trunk in late summer increases

ﬂ owering and fruiting (40–800%) in litchi trees that would have ﬂ owered

poorly in the spring. If no pronounced growth ﬂ ush has occurred in the 6

months before the ﬂ oral initiation period, or the trees are in poor condition

or have had a late-autumn vegetative ﬂ ush, they have increased ﬂ owering

(Menzel and Simpson, 1987). Trees to be girdled should be fertilized

immediately after harvest and irrigated to induce ﬂ ushing and then girdled in

late summer when the leaves have become fully matured (Fig. 9.1). Girdling

of limbs and trunks of trees that start ﬂ ushing in late summer has no signiﬁ -

cant e ect on trees that would have ﬂ owered profusely on their own. Early

recovery from girdling is associated with vegetative ﬂ ushing during winter

(Menzel and Paxton, 1986b).

Retention of litchi fruit after setting is a universal problem. Fruit

development is punctuated by four phases of abscission (Fig. 9.6), the ﬁ rst

occurring within 15 days of anthesis, in which more than 92% of pollinated

ﬂ owers drop due to endosperm degeneration and subsequent embryo abortion.

The second period of abscission is possibly due to degeneration of the embryo

sacs. Phase IV does not occur in fruits that have aborted seeds. There are many

causes of fruit drop, including unfavourable climatic conditions and nutrient

deﬁ ciencies. Spraying newly set fruit twice at 15-day intervals with 35–100 ppm

of 2,4,5-T and NAA progressively reduces fruit drop, improves fruit size and

even hastens ripening (Prasad and Jauhari, 1963). Lower concentrations also

reduce litchi fruit splitting, another serious problem in many areas. Growth

regulators (GA 100 ppm, NAA 20 ppm, 2,4,5-T 10 ppm, chlormequate 250

ppm) sprayed on litchi cv. ‘Rose Scented’ at the pea stage had reduced fruit

drop (Khan et al., 1976). Spraying ‘Early Seedless’ and ‘Calcuttia’ with 20

ppm IAA enhances fruit set; 50 ppm GA-3 increases fruit retention and 100

ppm GA-3 improves fruit weight, with a combination of IAA and GA-3 being

suggested (Singh and Lal, 1980).

Reduction of seed size or the production of seedless fruit has also been an

objective in the use of growth regulators. Kadman and Gazit (1970), using

232 Chapter 9

2,4,5-TP (trichlorophenoxypropionic acid), prevented fruit drop to a higher

degree and resulted in more than 75% of the litchi fruit having small seeds.

However, if the inﬂ orescence is ﬁ rst treated with 2,4,5-TP and then sprayed

with a combination of 2,4,5-TP and gibberellic acid, fruits are 50–100%

larger than those treated only once, and 90–100% of the fruits are seedless.

The development of forced ﬂ ower initiation in longan by the use of

potassium chlorate (Fig. 9.7) has extended the production area and also

assured more regular yielding (Yen et al., 2001). However, signiﬁ cant

variations in ﬂ owering application methods have been reported. The variation

is due to variety, developmental status of plants at forcing, soil conditions

and climate (Yen et al., 2005). Potassium chlorate is applied as a soil drench

(200–1000g per tree), either as the salt or in solution is more e ective than

as a leaf spray (1–2%), injection (1–5%) or trunk girdling (300–600 g).

Treatment with chlorate leads to ﬂ ower induction and the appearance of

ﬂ ower buds in about 40 days, though it can induce leaf chlorosis and drop.

Common bleach decomposes, especially at high temperatures to chlorate and

a level of ~4 g/l has been detected (Matsumoto et al., 2007). Trees treated with

7.6 l of household bleach (~30 g chlorate) were induced to ﬂ ower (Fig. 9.7),

and bleach was more e ective than 250 g of chlorate. The greater e ectiveness

of bleach suggests potentially rapid decomposition in the soil to chlorate. The

e ectiveness of bleach supports an earlier observation that water released

from soybean shoot factories induced longan to ﬂ ower. Bleach is used to

sterilize the seeds before germination and to wash down the equipment.

The rapid induction of ﬂ owers by chlorate means that a longan grower

can take orders for fruit to be delivered 6 months later under good conditions.

0102030

Days after full bloom

Relative abscission rate (%/day)

40 50 60 70

Huai Zhi

I II III IV

H-1224

Fig. 9.6. Litchi fruit abscission rate, taken as a mean over 2 years, occurs in at least

four stages (I–IV). Normal-seeded ‘Huai zhi’ (+) harvested 75–80 days after full

bloom and aborted-seeded ‘H-1224’ (·) harvested at 70–75 days after full bloom

(after Yuan and Huang, 1988).

Litchi and Longan 233

Another advantage of this treatment is that blocks of trees can be forced to

ﬂ ower sequentially to produce fruit almost year-round. Fruit quality is more

a ected by cultural management rather than potassium chlorate ﬂ ower

induction. The application of potassium chlorate has changed the pruning

methods. Heavy pruning after harvest is now used to control tree size, followed

by potassium chlorate application.

Fruit

Litchi fruit takes from 80 to 112 days to reach maturity from anthesis,

depending upon the cultivar and environment (Fig. 9.8). Litchi aril growth

begins about 25 days after anthesis and the aril growth then parallels total

fruit growth. The fruits show a dramatic increase in total sugars from about

3 to 16–20% during the rapid growth period of the aril. Photosynthesis in the

leaves behind the fruit cluster is more important than photosynthesis in older,

shaded leaves or stored starch in the stem (Hieke et al., 2002). The tart ﬂ avour

100

flowers

30 40 50 60

50 g

KCIO

250 g

KCIO

Bleach

Days from treatment

Flowering terminals (%)

70 80 90 100 110 120

Fig. 9.7. Induction of longan ﬂ owering with potassium chlorate and bleach

(redrawn from Matsumoto et al., 2007). No ﬂ owers were observed for the ﬁ rst 35

days.

234 Chapter 9

of immature litchi fruit is due to high organic acids. The increase in Brix/acid

ratio as fruits mature is due to the decrease in organic acids and increase in

sugars (Paull et al., 1984), contributing signiﬁ cantly to the litchi ﬂ avour. Peel

anthocyanins increase and chlorophyll decreases during this same late growth

phase. Cultivar di erences do not allow peel colour to be an accurate measure

of maturity. Late-season cultivars show a longer initial growth phase than the

early and mid-season cultivars.

The size and shape of the litchi fruit are characteristic for di erent

cultivars. ‘Chenzi’ has fruit averaging 23 g; other cultivars’ fruits can weigh

more than 30 g. The ratio of edible aril to seed is more important than large

fruit size. Most cultivars have medium to large seeds, occasionally producing

Mass (g)

(a)

Days from full bloom

60 80

Seed

Skin

Aril

Total

100

Mass (g)

(b)

Days from full bloom

60 80

Pericarp

Seed

Aril

Total

100 120

Fig. 9.8. The fruit growth pattern of (a) litchi cultivar ‘Groff’ fruit (after Paull et al.,

1984) and (b) longan cultivar ‘Dong bi’ fruit (after Ke, 1990).

Litchi and Longan 235

fruit with small, shrivelled seeds. The Hawaiian cultivar ‘Gro ’ has perhaps

the smallest-sized fruit (approximately 12.5 g), but produces small, shrivelled

seeds, ‘chicken tongue’, in about 95% of the fruit, greatly increasing the

edible portion to 50–70%. In cultivars with shrivelled seeds, little embryo

development occurs, and the seed growth that does occur stops 30–40 days

from anthesis.

Usually only one of the two locules in the litchi and longan ovary develops

to form a normal fruit. The other aborts and remains at the base of the normal

fruit. Occasionally, both carpels develop equally to form two normal fruit.

The aril tissue in litchi and longan develops from just above the degenerating

obturator and is formed by an outgrowth of the funiculus (Huang et al., 1983).

Aril growth parallels embryo development, though embryo development is not

required for litchi aril growth. If embryo development is arrested during the

liquid endosperm stage and when little embryo growth has occurred, the ﬁ nal

fruit is ﬁ lled with aril and a small aborted seed, called ‘chicken tongue’ (Huang

and Qiu, 1987). When no endosperm development takes place, no embryo or

aril development occurs and you get a ‘hollow’ fruit. Both of these conditions

relate to fertilization disorders. Aril development is not uniform and thus

overlaps at the chalazal end of the seed. The aril is therefore free from the seed

in both litchi and longan.

Longan fruit are brownish, globose to ovoid, 1.5–2.0 cm in diameter; the

skin is thin without protuberances and dull green when developing; the aril

is white, translucent and sweet, with an aromatic spiciness. The fruits show

a single sigmoid growth curve, with the major portion of seed development

occurring between 50 and 70 days from anthesis, reaching maturity in 100

days. During early development the seed is the major sink in longan fruit, and

aril growth occurs only after the seed has attained full size and maximum

weight, about 50 days after anthesis (Fig. 9.8b). Growth of aril accounts for

most of the increase of fruit weight during late development and reaches

60–70% of the fruit fresh weight. Growth periods were signiﬁ cantly di erent

among longan varieties (from 140 to 200 days) and are not correlated to ﬁ nal

fruit size.

Sugar accumulation in the longan aril begins after the main period of

seed development, 70–100 days post-anthesis (Ke, 1990). The fruits can

reach 25% total soluble solids and are ready for harvest when the total soluble

solids reach at least 17–20% and suitable fruit size (above 8–10 g). Sugar

accumulation in the aril begins after the main period of seed development,

70–100 days post-anthesis. The fruits show a dramatic increase in total sugars,

from about 3 to 16–20% during the rapid growth period. The phenomenon is

called ‘desweeting’ in China and Taiwan. The rate of desweeting varies with

cultivar. Fruits of slow-desweeting types can be retained on the tree longer,

and are better for adjustment of harvest time. The soluble solids of the cultivar

‘October’ in Taiwan can be maintained above 20% for 50 days.

236 Chapter 9

CULTIVAR DEVELOPMENT

Cytogenetics and genetics

There are suggestions that the litchi may have been derived from more than

one wild progenitor. Haploid chromosome numbers of 14, 15, 16 and, rarely,

17 have been reported, with diploid numbers of 28, 30 or 32. The diploid

number for longan is 2n = 30. It is possible to generate intergeneric hybrids

using litchi as the female parent with longan. The hybrid plants are similar to

the maternal parent with smaller leaves.

Breeding and selection

Like most single-seeded fruit, the litchi and longan do not lend themselves to

breeding by a controlled pollination system between two selected parents

(Zee et al., 1998). The highly heterozygous nature of the species means that

planting open-pollinated seeds derived from within a cultivar collection is

the usual procedure used in new cultivar development. For example, the

Hawaii litchi cultivar ‘Kaimana’ is a selected seedling of open-pollinated seeds

of ‘Hei Ye’.

Litchi genetic diversity is indicated by the large number of cultivars in

China and India, and these provide the basis for the development of new

cultivars. Singh and Singh (1954) reported that the 33 or so cultivars grown

in India are all selected from seedling populations derived from introduced

Chinese cultivars.

It is di cult to identify longan cultivars by skin colour alone. Useful

criteria for identiﬁ cation include the retention of total soluble solids after

harvest, crispness and smoothness of the ﬂ esh, and taste (Table 9.3).

Selection and evaluation

Galán Saúco (1989) has presented a detailed list of characteristics for a litchi

cultivar:

• Fruit: large, with small or shrivelled seed and a high proportion of edible

aril; bright red skin colour; long shelf-life and ability to retain skin colour

under storage conditions; ﬁ rm ﬂ esh with acceptable sugar/acid ratio; and

resistance to diseases.

• Tree: vigorous; precocious; regular and high yielding; resistant to water

stress, wind, soil salinity, diseases and insects; and adapted to regular

ﬂ owering under warmer temperatures in the tropics.

Litchi and Longan 237

Table 9.3. Fruit characteristics of selected litchi and longan cultivars.

Cropping regularity

Cultivar Synonyms Season Vigour

Fruit

quality

Fruit

wt (g)

Edible

% TSS

Flesh

colour

Skin

colour

Seed

size Tropics Subtropics

Litchi

Da zao Tai So early vigorous fair 24 72–77 15–18 milky white bright

red

large regular irregular

Hei ye Hak Ip,

Blackleaf,

Groff

mid moderate good 19 78 16–20 milky white dull red large irregular irregular

Huai zhi Wai chee late dwarf good 21 72 15–18 milky white dull red large irregular regular

Gui wei Kwai May (Mi),

Bosworth

mid vigorous very good 17 70–83 18–21 white light red mostly

small

irregular irregular

No mi ci No Mai Chee mid to late vigorous excellent 25 82–86 18–21 milky white bright

red

small irregular irregular

San yue hong Sum Yee

Hong

early medium fair 40 62–68 15–20 milky white bright

red

large

Chen zi Chen Family

Purple,

Brewster

early vigorous good 20 54–58 15–18 waxy white deep red large

medium

irregular irregular

Longan

Kohala mid spicy 15 regular

Sao-an-liao mid 15 62 13 dark

brown

small

Duan ru mid 13 14

Yang tao ye Carambola

leaf

mid 16 11

Fen ke mid crispy 11 66 20 white dark

yellow

medium

Continued

238 Chapter 9

Table 9.3. Continued.

Cropping regularity

Cultivar Synonyms Season Vigour

Fruit

quality

Fruit

wt (g)

Edible

% TSS

Flesh

colour

Skin

colour

Seed

size Tropics Subtropics

Daw good regular irregular

Chompoo excellent regular irregular

Biew Kiew excellent irregular

Fuyan Lucky eye late vigorous good 12 67 15 transparent

crispy

dark

brown

small regular

Wuyan Black round mid vigorous good 17 71 14 white light

brown

large regular

Shi xia Shek Yip, Shi

Yuan

mid vigorous excellent 10 69 19 white crispy dark

brown

small regular

Litchi and Longan 239

Sometimes a selection is elevated to a cultivar status by satisfying only a few

of the above characteristics (Table 9.3). Such a selection is ‘Gro ’, by virtue

of consistent bearing over a 7-year period, producing ﬂ owers usually several

weeks later than other Chinese cultivars grown in Hawaii and producing

aborted seeds in about 95% of the fruit. Average fruit size is 12.5 g, smaller

than other Chinese cultivars grown in Hawaii, but there is approximately 20%

more edible aril for the same weight of fruit (Storey et al., 1953).

Breeding for adaptation of cultivars to the higher temperature conditions

in the warm tropics is an important criterion (Menzel, 1983). Menzel and

Paxton (1986a), using glasshouses at high temperatures (30°C day/25°C

night) to evaluate litchi seedlings for low vigour, found this to be a useful

technique for initial screening prior to ﬁ eld evaluation of adapted genotypes

that would ﬂ ower and fruit under warm conditions. The rate of ﬂ ushing in

the glasshouse at high temperatures agreed with the relative vigour and

consistency of ﬂ owering of the parent cultivars in the ﬁ eld.

Similar criteria have been developed for longan (Table 9.3). Longan fruit

criteria include retention of total soluble solids after harvest, crisp and smooth

ﬂ esh, good taste, uniform size and high aril content.

Cultivars

According to Gro (1921), Chinese nurserymen recognized the di culties in

perpetuating the desirable characteristics of highly regarded cultivars under

conditions other than those in which the fruit originated. The environment

profoundly inﬂ uences cultivar characteristics, and this may explain the large

number of cultivars, with 74 cultivars mentioned in Wu Ying Kuei’s list of very

ancient origin. Among the many known cultivars in China, the cultivars ‘San

yue hong’ (‘Sum Yee Hong’), ‘Shui dong’ (‘Souey Tung’), ‘Fe zi xiao’ (‘Fay Zee

Siu’), ‘Hei ye’ (‘Haak Yip’), ‘Gui wei’ (‘Kwai May’), ‘No mi ci’ (‘No Mai Chee’)

and ‘Huai zhi’ (‘Wai Chee’) in Mandarin, with the Cantonese in brackets,

are most widely grown (Table 9.4). Sixty-seven cultivars and selections are

described for Guangdong, with 26 of these being major commercial cultivars

(Anon., 1985). ‘Brewster’ (‘Chen Zi’, ‘Chen Family Purple’) trees are vigorous,

large and one of the faster-growing cultivars. ‘Hei Ye’ has been observed to be

a slow grower, low by comparison to cultivars such as ‘Chen Zi’ and ‘Gui Wei’

of the same age but becomes spreading.

Cultivars in Thailand are ‘Da zao’, ‘Hei ye’, ‘Huai zhi’ and ‘Hong huey’

(syn. ‘Mau mong’) (Table 9.4). Other cultivars are ‘Kim cheng’, ‘Hong thai’,

‘Ohia’ (syn. ‘Ouw’, ‘Hei ye’, ‘Baidum’), ‘Gui wei’, ‘Gro ’, ‘No mi ci’, ‘Chen zi’

and ‘Mauritius’. In Australia, the cultivars most often planted are ‘Da zao’,

‘Bengal’, ‘Hei ye’, ‘Huai zhi’ and ‘No mi ci’. In the USA, Florida cultivates

primarily ‘Brewster’, ‘Mauritius’ and ‘Sweet Cli ’. The ‘Mauritius’ in Hawaii

is di erent from the Florida ‘Mauritius’. In Hawaii, most of the plantings

240 Chapter 9

consist of ‘Da zao’, ‘Gro ’, ‘Hei ye’ and ‘Brewster’. In subtropical South Africa,

particularly in the Transvaal Lowveld, the Soutpansberg and Natal Coast

areas, ‘Mauritius’ is the principal commercial cultivar and is a synonym of

‘Gui Wei’. The genetic diversity has led to many synonyms and confusion,

along with mislabelling of di erent cultivars, with isozyme analysis and

molecular markers now beginning to separate the di erent lines (Aradhya et

al., 1995; Viruel and Hormaza, 2004).

Table 9.4. Major litchi and longan cultivars grown in different countries (after

Menzel and Simpson, 1990); name in national Chinese pronunciation unless

otherwise indicated (*).

Country

Main growing

area Major litchi cultivars Major longan cultivars

China Guangdong Huai zhi, Hei ye, Sun

yue hong, Gui wei,

No mi ci

Shixia, Chuliang

Guangxi Huaizhi, Heiye, Dazao,

Sanyuehong, Guiwei,

Nomici

Fujian Shui dong, Hei ye, Da

zao, Chen zi, Fu yan,

Wu yuan, Shi xia

Fuyan, Wulongling,

Chike

Taiwan Taichung Heiye, Nomici,

Yuhebao, Huaizhi,

Sakengzong,

Sanyuehong

Chienliou*, Yangtaoye,

Saoandiao, Duanru,

Fenke

Thailand Chiangmai,

Lamphum,

Fang

Da zao, Huai zhi,

Hei ye

E-Daw*, Chompoo*

(Seechompoo), Haew*,

Biew kiew*, Dang*,

Baidom*

India Bihar State Shahi*, Rose Scented*,

China*

Madagascar Wet coastal belt Da zao

South Africa Transvaal –

Lowveld

Da zao

Reunion Da zao

Mauritius Da zao

Australia Eastern coastal

strip

Da zao, Bengal*,

Huaizhi, Gui wei,

Salathiel*

USA Hawaii Da zao, Kaimana*, Hei

Kohala*, Ilao*, Wai*,

Sweeney*

Florida Brewster* (Chen zi) Kohala*, Chompoo*,

Homestead #1* & #2*

Litchi and Longan 241

Although more than 400 longan cultivars have been developed in

China, less than 10 are economically important (Chian et al., 1996; Liu and

Ma, 2001). More than 200 clonal cultivars are maintained at the National

Longan Germplasm Repository at the Fruit Research Institute, Fujian.

More than 50 cultivars have been identiﬁ ed in Taiwan, though less than 5

cultivars are widely cultivated (Yen and Chang, 1991). In Thailand, ‘E-Daw’

accounts for more than 90% of longan production (Subhadrabandhu and

Yapwattanaphun, 2001). There are about 20 cultivars of longan in Australia,

mostly introduced from China, Thailand and the USA. A longan clone

‘Kohala’ has been released in Hawaii and displays proliﬁ c vegetative growth

and produces heavy crops in Hawaii as well at Homestead, Florida. There are

numerous longans, with a wide range of characteristics (Table 9.3). Molecular

markers are being developed to identify longan cultivars.

CULTURAL PRACTICES

Propagation

Sexual

Seed propagation is used to produce litchi seedlings from selected cultivars for

breeding and selection studies and for production of rootstocks for grafting.

Litchi seeds remain viable in the fruit for about a month after harvest with a

moisture content of 45%; viability is soon lost within 4–5 days once removed

from the fruit and the moisture content falls below 27%. Seeds packed in moist

sphagnum moss may be shipped, though seeds frequently germinate in the

packing within a week. Germination and seedling development is improved

by the use of the large seeds and mycorrhizal soil for germination. Seeds

germinate within 4–10 days in soil, sand, vermiculite, perlite, peat, wood

shavings or mixtures of these materials, with adequate moisture and aeration.

Seedlings are not used for new planting as they have a long juvenile phase of

up to 10 years.

Longan seeds are also recalcitrant and quickly lose their viability after

removal from the fruit. Similar to litchi, longan seedlings have a long juvenile

period of greater than 8 years.

Asexual

Litchi and longan are usually propagated by air-layering, the method used by

Chinese propagators for centuries. Moist peat or sphagnum moss is wrapped

around the girdled area of a branch and held in place with plastic sheets

cut to about 25–30 cm

, with the ends fastened with string or some taping

material, such as plastic electrician’s tape. Su cient roots are formed in 8–10

weeks, and the success rate is nearly 100%. There is no need to apply growth

242 Chapter 9

regulators to enhance rooting, though some recommend a lanolin paste with

250 ppm IBA, 100 ppm 2,4,5-T, and IAA or IBA at 500 ppm.

Cuttings with two to three leaves from girdled and ungirdled branches of

‘Brewster’, ‘Gui Wei’ and ‘Hei Ye’, treated with the sodium salt of NAA, IBA

and their mixtures and misted or not in a polyethylene enclosure give poor

results. Others have obtained 93% rooting and 100% survival by using green,

woody cuttings dipped in 5000 ppm IBA and rooted under intermittent mist.

The variable and often low rate of success in litchi grafting is attributed

to stock–scion incompatibility, poor cambial contact, grafting at the wrong

physiological stage and poor management after graftage (Menzel, 1985).

Graft incompatibility is suggested when only 20% of girdled ‘Brewster’ scion

and 10% of ‘Gui wei’ are successful on rootstocks of the same cultivars.

Histological studies of the graft unions between ‘Hei ye’ and the above two

cultivars show a slow rate of proliferation of callus tissues. Currently, there

is generally a lack of knowledge on the graft compatibility between litchi

cultivars. Proper culture of rootstocks and preparation of scion-wood (girdling

for starch accumulation), proper stage of maturity of scion-wood, appropriate

post-graft environment, particularly high humidity, and other factors

contribute to more consistent success in grafting.

Grafting is used for longan, with semi-hard terminals as scions. The scions

are cleft-grafted into a node subtended by a leaf in Australia. This grafting is

done on to 12–18-month-old rootstocks. In China, whip grafting, side grafting

and budding are used. Top-grafting is used to top work large trees.

Field preparation

Deep ripping may be necessary if the soil is compacted. Liming to pH 5.0–5.5

should be carried out and manure incorporated before planting. Litchi

trees tolerate poor drainage but do not grow well in standing water. Surface

drainage should be installed if such conditions exist. If nematodes are

expected to be a problem, fumigation should be carried out. Longans require

well-drained alluvial soils for good development.

Transplanting and spacing

Sun-hardened trees (6–12 months old) can be planted out at any time of year

if there is su cient moisture available and there is no chance of frost. Light

mulching (100 mm) after fertilization is beneﬁ cial for young litchi trees.

Seedlings should start to produce fruit in 6–10 years and asexually propagated

trees in 3–5 years.

Spacings of 5–12 m, depending upon cultivar size, are used. ‘Gui wei’

is a very vigorous tree, ‘Hei ye’ being moderate, while ‘No mi ci’ is a smaller

Litchi and Longan 243

cultivar. In Florida, litchi are planted at 7 m × 4 m, with regular mechanical

pruning to avoid overcrowding (Campbell and Knight, 1987), and in

subtropical areas 6 m × 6 m spacing is possible (Galán Saúco, 1990).

Windbreaks are necessary for young and mature trees for both crops. This

is essential because trees propagated by air-layering do not have a tap root and

are easily uprooted by winds.

Irrigation

Regular irrigation is essential during the growth of young trees. During dry

periods irrigation may be needed at 2- or 3-week intervals. Moisture control

is applied when the trees reach ﬂ owering age. In China, litchis are grown

along canals, on dykes around paddy ﬁ elds and around village ponds, and

no irrigation is practised. Moisture should be withheld during autumn and

winter to discourage vegetative growth and promote ﬂ owering (Fig. 9.1).

High soil moisture tension for 6 months, beginning mid-summer, or even for

3 months, beginning in late summer, promotes ﬂ oral initiation and fruit set

by inhibiting emergence of vegetative ﬂ ushes (Nakata and Suehisa, 1969).

Once the inﬂ orescence has appeared and throughout fruit development,

adequate moisture is necessary. Irrigation should be terminated a few weeks

before harvesting. Moisture stress under non-irrigated situations can cause

developing fruit to ripen prematurely, even before the aril has fully developed.

Fruit growth will resume if water is provided, leading to fruit splitting. Copious

irrigation immediately after harvest is desirable to encourage new shoot

growth (Fig. 9.1). In areas with dry summers, irrigation is necessary, followed

by limb girdling in late summer to discourage further vegetative ﬂ ushing and

to accumulate carbohydrates in the trees during the autumn months (Nakata,

1953). This practice is necessary in areas where climatic conditions do not

enforce a natural period of tree dormancy in the winter.

Pruning

Less research has been done on the need for and e ectiveness of pruning

longan trees than litchi. During the ﬁ rst 2–3 years, all side shoots up to

0.8–1.0m should be removed from litchi, as these will form low-hanging

branches, which interfere with cultivation. In bearing litchi trees, even

branches 1.5 m high will bend to the ground when laden with fruit. In

Australia, the main terminals of 3–4-year-old trees are headed back in the

spring (prior to ﬂ ushing) in vigorous cultivars, to create a more compact tree

with many terminals, thus increasing the potential bearing surface (Menzel

et al., 1988a). Approximately 16 cm is pruned from the tip, and from each

pruned branch an average of three new terminals are produced. A pruning

244 Chapter 9

system is practised in Taiwan to maintain small tree size (<2 m), to obtain a

wine-glass shape, to encourage regular ﬂ owering and for ease of management

and harvesting (Yen, 1995). An inverted cone approach is also used: wide at

the bottom and narrow at the top (3–4 m high), with mechanical trimming

to maintain shape. Tree thinning is also practised after harvest, to open the

canopy for light penetration, which is beneﬁ cial for inﬂ orescence formation

(Lin et al., 1991). Light pruning sometimes encourages several weak ﬂ ushes

and results in poor ﬂ owering. Severe heading-back of a tree is harmful to

future inﬂ orescence formation. Little or no pruning is done in India and

yields are said to be heavier than with the pruning practised in Taiwan.

Canopy thinning after harvest is done in India. Panicle thinning or pruning is

sometimes practised. Girdling is practised in October to inhibit new ﬂ ushes; if

too severe the next year’s growth will be reduced (Yen, 1995).

Fertilization

Fertilization practices of commercial litchi (Table 9.5) and longan orchards

di er due to di erences in climate, soil, availability of di erent kinds of

organic and inorganic fertilizers and other factors. The Chinese practice

for litchi on alluvial or red basaltic soils provides 300–400 g of urea, 100 g

superphosphate and 25–50 kg animal manure to large trees just after

harvest, but not later than July. At blossoming, 100 g urea/tree or mixed

NPK is applied. To prevent fruit drop, trees are sprayed with 0.1–0.2% urea;

sometimes 0.2% magnesium sulfate is added.

A light fertilization application should be given with care immediately

after ﬁ eld transplanting, due to the sensitivity of litchi roots to fertilizer burns.

Heavy applications should be delayed a year or after one or two growth

ﬂ ushes. One-year-old trees are given ~30 g urea/plant/month. Also, 30 g of

a high-analysis mixed fertilizer such as 15-4-11 is given every 3 months with

Table 9.5. General guide for litchi fertilization.

Year Fertilizer formation Time of application Amount (g/tree)

First year 14-14-14 At planting time 125

14-14-14 At 4 months 125

14-14-14 At 8 months 125

14-14-14 At 12 months 125

Second year 14-14-14 Once/4 months 250

Third year 14-14-14 Once/3 months 455

Fourth year 14-14-14 Once/3 months 455

Fifth year 10-20-20 Appearance of ﬂ owers

(Feb, Mar)

1000–1500

14-14-14 After harvest (May–June) 1000–1500

Litchi and Longan 245

the urea. Fertilizer in subtropical areas is withheld during cold months to

prevent ﬂ ushing.

In Australia, general recommendations for 5-year-old trees are: 150 g

urea, 300 g single superphosphate and 150–200 g potassium sulfate per

application. These amounts are increased by 20–30% each year until year 15,

when each application rate increases to 1200 g urea, 1200 g superphosphate

and 600–800 g potassium sulfate. No fertilizer is applied to bearing trees in

the spring, to prevent vegetative ﬂ ushing in the autumn, in order to increase

the prospect of good ﬂ owering. Three applications of a complete fertilizer,

such as triple-14 at 114 g per tree the ﬁ rst year and increasing to 227 g per

application in the second year, are used in Hawaii. In the third year, two or

three applications at 454 g per application are applied. For bearing trees a

general rule of thumb of 0.90 kg of a complete fertilizer for every 2.54 cm

of trunk diameter is given upon completion of harvest to encourage summer

ﬂ ush. An application in late winter or early spring before ﬂ oral initiation has

begun can result in a vegetative ﬂ ush rather than a ﬂ ower ﬂ ush. The main

fertilization is applied immediately after harvest in the summer (Fig. 9.1),

followed by irrigation and the annual limb girdling.

Critical nutrient periods are before ﬂ owering and fruit set, several weeks

after fruit set and after harvest. Litchi leaf nitrogen should be ca. 1%. Leaf

samples for analysis are taken twice a year, once at the end of harvest and

the second at ﬂ owering, with only P and K applied during fruit set to avoid

vegetative growth from N application. Minor elements are applied once a year

at the end of the cold period.

Erratic bearing

Litchi trees 7–8 years old can produce up to 45 kg. Potential yields for 10-year-

old trees are 50–70 kg, 15-year-old trees at 100 kg, and 20–24-year-old trees

at 150–180 kg (Campbell and Knight, 1987). Occasionally, yields can be as

high as 500 kg in very old trees. Apparently, potential yields can continue to

increase with older trees, as has been demonstrated in China.

The litchi can be a heavy bearer when conditions are favourable for

fruiting; however, considerable year-to-year variation in yields occurs wherever

grown (Fig. 9.9). Erratic ﬂ owering can be due to unfavourable weather

conditions, and even if ﬂ ower production is consistent, fruit set problems

contribute to variable yields (Chapman, 1984). Cultivars are very particular

about their climactic requirement (Table 9.1); trees propagated from good

bearing trees and planted in another location are known to have produced

fruit for a few years and later ceased to produce for years.

Fruit bearing is dependent upon a number of crucial phases, which need

to be optimized throughout the year (Fig. 9.1). The inﬂ uence of cultivar,

pruning and tree management needs to be integrated. Both species need to be

246 Chapter 9

stimulated to leaf growth after harvest; this is followed by a period of rest, then

ﬂ oral induction and development. These ﬂ ushes are induced by fertilization

and rainfall or irrigation (Yen, 1995). There can be more than one ﬂ ush of

leaves during the 5 months after litchi and longan harvest, with leaves being

forced to mature and growth restricted after this phase. While mature leaves

are essential for ﬂ owering, the presence of young, expanding foliage in the

cool season is inhibitory to inﬂ orescence formation; if removed, ﬂ owering

capacity increases (Lin et al., 1991). In autumn, young, expanding leaves

can be removed mechanically or with a low rate of ethephon (1500 ppm); a

higher rate will abscise more mature leaves. Tree girdling in late summer can

be used to limit new shoot growth. The conditions for ﬂ oral induction, besides

tree condition, are temperature and water stress for litchi and temperature and

possible nitrogen stress for longan. The terminal nature of the inﬂ orescence

inhibits further main axis development, with lateral shoots on branches that

have fruited continuing further shoot growth, with only 22% that produce

ﬂ owers in the following season.

Poor synchronization of ﬂ ushing and ﬂ owering within an orchard

increases management problems. Cultivars vary in their requirements for

induction, leading to early- and late-season bearers.

Pest management

Diseases

A number of disease organisms infecting litchi fruit are listed in the literature,

but none are considered to be serious and all are of a postharvest nature.

Aspergillus spp., Botryodiplodia theobromae, C. gloeosporioides (anthracnose),

Cylindrocarpon tonkinense, Pestalotia sp., Penicillium and Alternaria can cause

1970

100

1973 1976 1979 1982

Year

Yield (kg / tree)

1985 1988 1991

Fig. 9.9. Change in litchi production at Beilu, Guangxi from 1971. Improved

management practices were used after 1981, which led to increased production and

reduced, but did not eliminate, year-to-year variation in yield per tree (Mo, 1992).

Litchi and Longan 247

some postharvest problems. Anthracnose is a problem in Florida, and the

cultivar ‘Mauritius’ is especially susceptible, the fungus a ecting young fruit

and causing fruit drop. Many of these fruit fungal infections are secondary in

nature, as the organisms enter the fruit only when the fruit skin is damaged.

Puncture sites from fruit ﬂ y oviposition are excellent points of entry.

A serious disease of longan in China and Hong Kong is witches’ broom,

caused by a virus. The virus causes serious deformity of the inﬂ orescence

(Liu and Ma, 2001). It is transmitted by vegetative propagation and is seed-

transmitted.

Nematodes have not been reported as a serious threat to litchi cultivation.

However, tree decline in Natal and Transvaal is associated with two species of

nematode. Roots become ‘stubby’ and brown in colour, and secondary feeder

root development is inhibited.

INSECTS

Insects are of greater concern (Table 9.6) in litchi production than diseases.

The erinose mite (Aceria litchii) is probably the most universal, having been

reported from many widely scattered areas. It attacks the young leaﬂ ets,

producing a thick growth of light brown to reddish-brown, felt-like hair on

the undersurface. The worm-like mite is not visible to the naked eye and is very

speciﬁ c to litchi. Occurrence of this mite coincides with periods of new growth,

regardless of season or locality, and in severe cases new shoots on the entire

Table 9.6. Insect pests of litchi.

Common name Organism Parts affected Region

Erinose mite

Aceria litchii (Eriophyes

litchii)

Foliage universal

Leaf miner

Conopomorpha sinensis

Foliage India and Asia

Rose beetle

Adoratus sinicus

Foliage of

young

plants

Hawaii

Trunk borer

Anoplophora macularia

Trunk Taiwan

Bark borer

Salagena sp.

Bark/wood South Africa

Shot hole borer

Xyleborus fornicatus

Branches India

Conopomorpha sinensis

Fruit China

Litchi moth

Argyroploce peltastica

Fruit South Africa

Macadamia nut borer

Cryptophlebia ombrodelta

Fruit Australia

Litchi stink bug

Tessartoma papillosa

Fruit China

Mediterranean fruit ﬂ y

Ceratitis capitata

Fruit South Africa

Natal ﬂ y

Ceratitis rosa

Fruit South Africa

Oriental fruit ﬂ y

Dacus dorsalis

Fruit Hawaii

248 Chapter 9

tree can be a ected. It is e ectively controlled by sprays of wettable sulfur at

2.3 kg per 378 l of water. It does not infest other relatives in Sapindaceae.

In Taiwan, a trunk borer (Anoplophora macularia) can cause death

of trees within a few months by boring into the trunk and damaging the

conducting tissues. The litchi stink bug can cause serious damage to fruit;

the bug is e ectively controlled by a parasite, Anastatus sp. In Australia, the

macadamia nutborer (Cryptophlebia ombrodelta) is considered a serious fruit-

damaging insect.

Mediterranean fruit ﬂ y (C. capitata) does not attack either species, except

where the fruit skin has been broken by other means and the pulp is exposed.

The Oriental fruit ﬂ y (D. dorsalis) does infest these fruit, causing punctures,

which are often the focus of entry of fungal organisms that cause fermentation

and decomposition. Other fruit ﬂ ies can be serious pests in other countries.

Other pests are birds and fruit bats. In Hawaii, the White-eye (Zosterops

palpebrosus) and the bulbul (Pycnopus cafer) can cause severe damage as fruits

approach maturity. Fruit bats (Pteropus sp.) or ﬂ ying foxes have caused severe

losses in South Africa and Australia.

Weed control

Weed control is most important from the time of ﬁ eld transplanting up to 3

or 4 years old. As trees grow and expand horizontally, there is a decreasing

amount of weed growth underneath the canopy, due to shading. Use of

polyethylene mulch about a metre square around the plant at transplant

time reduces weed growth near the plant. Litchi are reported to be adversely

a ected by organic mulches around the base.

HARVESTING AND POSTHARVEST HANDLING

Harvesting

Fruits are ready for harvest when they attain full red colour. Fruits harvested

before full maturity are acid and do not ripen further or improve in ﬂ avour.

These are non-climacteric fruit and do not respond to ethylene. Litchi and

longan are harvested by cutting or breaking o the entire panicle with the

cluster of fruit. The practice is to remove the panicle together with a variable

portion of last year’s wood in many countries, to enhance the production of a

higher number of terminals that may ﬂ ower next spring (Galán Saúco, 1989).

Panicles without fruit are also cut, as the presence of old panicles is reported

to delay the next ﬂ ush. In small orchards, bamboo or aluminum tree-pruning

poles and tall ladders are used. In large orchards, mechanical ‘cherry picker’

platforms greatly facilitate harvesting. Harvesting fruit clusters on older,

Litchi and Longan 249

large trees is di cult and time-consuming. The trend of the last 20 years is

to maintain tree height at less than 3 m. This height allows all management

practices and harvesting to be carried out from the ground, which is faster and

more e cient.

Harvesting is not done in the afternoon in China, as fruit colour is said to

become dull more rapidly, or on rainy days, as wet fruit is said to break down

rapidly. Panicles of fruit are packed in straw baskets or cartons containing

15–20 kg of fruit. Green leaves are also packed with the fruit, to reduce

damage in transit and assist in providing moisture and preserving fruit colour.

Harvested fruit are never exposed to sun, to prevent rapid drying.

Longan fruit maturity is judged by fruit shape, skin colour and the ﬂ avour

of each cultivar. Most fruit can be picked from a tree with one harvest, unless

multiple ﬂ owerings have occurred. No deﬁ nite harvest index exists for longan,

but growers usually note the changes in skin appearance: mature fruit develop

a smooth and darker skin. Fruits are clipped from the stem, as hand removal

often leads to some of the skin being removed. One-piece ﬁ breboard crates,

either 4.5 kg or 2.25 kg, with a plastic liner, are used, if not already packed in

polystyrene punnets.

Postharvest treatments

The major problem in marketing these two fresh fruits is the rapid skin

browning, which makes them unattractive, although the aril remains edible

(Paull and Chen, 1987). In many Asian countries fruits are sold still attached

to the panicle in bunches, while in western countries individual fruits in

punnets are marketed. Much of the postharvest research has been directed

towards the prevention of pericarp browning in storage and marketing of

fresh fruit. The ﬁ eld skin colour of both litchi and longan can be retained by

a sulfur dioxide acid treatment applied before insect disinfestation. All longan

exported from Thailand are so treated, as are much of the litchi from some

other countries. The sulfur dioxide treatment is not approved in the USA.

Retention of litchi red pericarp colour for longer periods has been

demonstrated by wrapping fruit in PVC ﬁ lm or bagging in polyethylene bags

and placing in storage temperatures of 0–10°C (Paull and Chen, 1987).

Commercial quantities (5.4 kg) of litchi and longan packaged in large

polyethylene bags and twisted closed, or individual fruits in punnets placed

in cardboard cartons and sealed are best stored at 2°C for up to 32 days. At

the retail level, all fruit not on display should be kept under refrigeration,

preferably as close as possible to 0–2°C. If surface transportation is used

instead of air freight, properly packaged fruit should be shipped at 0–2°C. Skin

colour and ﬂ avour of fruit is retained for about a month.

Grade standards are similar for both species and are generally set between

the shipper and buyer. Small, poorly coloured, immature or damaged fruit

250 Chapter 9

are culled. Similar mechanical injury to litchi tubercles leads to a site for skin

browning. Soluble solids should be greater than 15% and acid levels low.

Longan pre-cooling is carried out by room or forced air cooling. Longan

in plastic baskets can be hydrocooled, though hydrocooled longan should not

be treated with sulfur dioxide. Sulfur dioxide fumigation damages hydrocooled

fruit skin, producing brown spots on both the inner and outer skin surface and

greater SO

residues remain on the fruit. Sulfur dioxide treatment of fruit to be

sold as fresh is not approved in the USA and restricted in Europe.

The storage recommendation for longan is 4–7°C and 90–95% RH. Fruit

can be held for 2–3 weeks, though the skin losses it yellowish coloration and

becomes brown. At lower temperatures, there is a rapid loss of eating quality.

At storage temperature less than 5°C, fruits develop a slight o -ﬂ avour after

about 1 week. Peel colour of longan stored at 0°C turns dark brown, while

-fumigated longan remain yellowish-brown. The dark brown peel of

longan that develops at very low temperatures is regarded as chilling injury.

When fruits are stored above 10°C, postharvest disease is of concern.

Controlled atmosphere studies have been reported, though modiﬁ ed

atmosphere storage in 0.03 mm polyethylene bags has been tested for 7 days

at room temperature, then 35 days at 4°C. A modiﬁ ed atmosphere of 1–3%

oxygen delays browning and maintains soluble solids and vitamin C content

in litchi. With 1% O

treatment and at carbon dioxide greater than 10–13%

an o -ﬂ avour develops and a build-up of ethanol occurs.

Irradiation studies have shown that litchi and longan for export can be

irradiated at 250 Grays. Hot–cold disinfestation protocols and cold treatment

for fruit ﬂ y disinfestation can be used for litchi and longan (Paull et al., 1995).

UTILIZATION

Important producing areas are China, India, Thailand, Taiwan, South Africa,

Mauritius and Australia. Proximate composition of litchi and longan indicates

they are a poor source of calcium, iron, thiamine and riboﬂ avin and a fair

source of phosphorus, and do not have provitamin A. They are a good source

of niacin and ascorbic acid (Table 9.7). Both fruits are usually eaten fresh

and can be preserved in a variety of ways. Dried litchi and longan, popularly

known as a ‘nut’, and canning are the most common. Peeled litchi fruit may

be canned in a 40% syrup, containing 0.2% citric acid. Hand-peeling of the

skin is the usual method, though a hot-lye dip and mechanical peeling are

used. The canned litchi, if fresh fruit are not available, are added to rare and

dainty dishes, and restaurants serve delicious litchi dishes with meat or with

syrup dressings.

Litchi and Longan 251

Fresh litchi packed in polyethylene bags can be quick-frozen and stored

for more than a year and still be edible, with the skin colour and ﬂ avour

reasonably well preserved. Fruit can be sun-dried in approximately 20 days;

two-thirds of the moisture is removed. Oven-drying can be used to shorten

the drying time, but care must be taken to use relatively low temperatures

of around 40°C, as higher temperatures tend to caramelize the sugars and

produce a burnt ﬂ avour and bitterness.

FURTHER READING

Galán Saúco, V. (1989) Litchi Cultivation (Menini, U.G. FAO Coordinator). FAO Plant

Production and Plant Protection Paper No. 83. FAO, Rome, Italy (In Spanish).

136pp.

Menzel, C.M. (1983) The control of ﬂ oral initiation in lychee: a review. Scientia

Horticulturae 21, 201–215.

Menzel, C.M. and Waite, G.K. (2005) Litchi and Longan. CABI Publishing, Wallingford,

UK.

Menzel, C.M., Watson, B.J. and Simpson, D.R. (1988) Longans – a place in Queensland’s

horticulture? Queensland Agriculture Journal 115, 251–265.

Table 9.7. Proximate composition of 100 g edible portion of litchi (‘Gui Wei’) and

longan (Wills et al., 1986; Morton, 1987; Wenkam, 1990). The edible portion of

litchi and longan is ca. 72%.

Litchi Longan

Water (g) 77.6 83.5

Energy (kJ) 335 –

Protein (g) 0.94 0.84

Lipid (g) 0.29 0.44

Carbohydrate (g) 20.77 14.9

Fibre (g) 0.16 0.32

Ash (g) 0.37 0.43

Minerals

Calcium (mg) 4 9

Iron (mg) 0.37 0.4

Magnesium (mg) 16 –

Phosphorus (mg) 35 36

Potassium (mg) 255 170

Sodium (mg) 7 3

Vitamins

Ascorbic acid (mg) 40.2 42

Thiamin (mg) 0.035 –

Riboﬂ avin (mg) 0.084 0.05

Niacin (mg) 1.91 –

Vitamin A (IU) 0 –

252 © CAB International 2011. Tropical Fruits, 2nd Edition, Volume 1

(R.E. Paull and O. Duarte)

MANGO

Mango (Mangifera indica L.) is also known as manga (Tamil), mangga (the

Philippines, Malaysia, Indonesia) and manguier (French). It is one of the

best-known and most widely cultivated tropical fruit species, with production

occurring in most countries in the tropics and subtropics. The fruit is marketed

fresh, dried and as a juice, and is used as a source of ﬂ avours, fragrances and

colourants.

BOTANY

Mango (M. indica L.) belongs to the family Anacardiaceae, also known as the

cashew family, with about 75 genera and 700 species, mostly tropical, with

some subtropical and temperate species. Common nut-bearing species include

Anacardium occidentale L., cashew nut, and Pistacia vera L., pistachio nut. Other

related fresh fruits are in the genus Spondias: the yellow mombin or hog plum

(Spondias mombin L.), the ambarella or June plum (Spondias cyhterea or Spondias

dulcis Forst.), and the purple mombin (Spondias purpurea L.). Another species

belonging to this family is the marula (Sclerocarya birrea spp. ca ra Sand) of

Africa.

The genus Mangifera consists of 69 species but not all bear edible fruit. The

mango fruit is large, ﬂ eshy and sometimes ﬁ brous (Fig. 10.1). Other species in

the genus bearing edible fruit include Mangifera altissima Blanco, Mangifera

caesia Jack., Mangifera foetida Lour., Mangifera lagenifera Gri ., Mangifera odorata

Gri ., Mangifera zeylanica (BL) Hooker and Mangifera sylvatica Roxb.

Origin and distribution

The mango originated in the Indo-Burma region and has been cultivated

in India for more than 4000 years. This fruit is intimately associated with

the Hindu religion and there are numerous ancient Sanskrit poems praising

Mango 253

(a)

(b)

3 mm

Fig. 10.1. Leaf, ﬂ owering panicle – (a) male ﬂ ower with one functional stamen and

four smaller, non-functional stamens with no ovary and (b) hermaphrodite ﬂ ower

with a large ovary with a single stigma and a single large stamen – and fruit of

mango.

254 Chapter 10

the blossoms and fruit (Singh, 1960). Indian traders and Buddhist priests

probably introduced the mango into Malaysia and other east Asian countries

during the 4th or 5th century  and to the Philippines between  1400

and 1450. The Portuguese, the ﬁ rst Europeans to establish trade routes

with India, transported the mango to East Africa and Brazil. Spanish traders

took the mango from the Philippines to the west coast of Mexico before the

English arrived in the Hawaiian Islands in 1778. The mango was introduced

into Hawaii from the west coast of Mexico between 1800 and 1820, with

credit being given to Don Francisco de Paula Marín, a Spanish horticulturist.

Apparently, the Brazilian introductions were spread to Barbados and to other

islands in the Caribbean area. Mango is now found in all tropical areas, as

well as many subtropical regions of the world, attesting to its wide range of

adaptability.

ECOLOGY

Soil

The tree is not exacting with regard to soil, although ﬂ at alluvial soils with

pH 5.5–7 and a soil depth of at least 1 m are preferred. Freely drained oxisol

soils, such as the deep volcanic soils in Java and the Philippines, are favoured.

It can grow in 40 cm-deep soils in Florida (Malo, 1972), 75 cm in South

Africa (Mostert and Abercrombie, 1998) or 80 cm in the Canary Islands

(Galán Saúco, 2009). A hard layer or hardpan in the soil proﬁ le can limit

root penetration and needs to be broken by subsoiling. In fertile soil, minimal

nutritional problems can be expected. Exchangeable aluminium, which

can be toxic, should be less than 30 ppm, and the tree is sensitive to saline

conditions. Calcareous soil with a high pH and salinity problems limit mango

development, although in Israel, mango is grown in very sandy soils, as well as

in calcareous soils (>38% CaCO

) with a pH close to 9 (Whiley and Scha er,

1997). Suitable rootstocks have been selected and used in areas where these

soil types exist, as well as in saline soils.

Climate

Rainfall

Mangoes are very drought-tolerant with a deep root system, which enables it

to capture water and nutrients from deep in the soil proﬁ le. The tolerance of

drought is also associated with the leaves and their latiferous cells remaining

turgid through an internal osmotic adjustment (Scha er et al., 1994). The tree

can withstand occasional ﬂ ooding and it is seen growing and producing fruit

on the banks between ﬂ ooded rice paddies. Good rainfall distribution is crucial

Mango 255

for ﬂ owering and fruit set, rather than total rainfall. A dry period is necessary

for reliable mango production, as it promotes ﬂ ower induction and improves

ﬂ owering intensity and synchrony, especially if the dry period coincides with

cool weather (Fig.10.2). In tropical high-rainfall areas, ﬂ owering is more

erratic and yields are low, with excessive vegetative growth. Flowers are very

susceptible to the disease anthracnose, particularly when rainfall occurs

during ﬂ owering, and low rainfall is preferred at this stage. Irrigation must be

applied regularly to prevent water stress during early fruit development when

cell division occurs and to produce a vegetative ﬂ ush after fruit harvest.

Temperature

Mango can be grown to 1200 m in the tropics, although the best production

occurs at less than 800 m. A temperature around 33°C seems to be the ideal

for ﬂ owering and fruit maturation and between 25 and 27° for vegetative

growth (Galán Saúco, 2009). The tree can endure up to 48°C during fruit

development if su cient irrigation is available, though at 40°C some leaf

damage can occur. Pollen viability declines if it develops at higher than 35°C

or below 15°C (Fig. 10.3). The lower limit for vegetative growth is 15°C

(Whiley et al., 1988), with the damage minimum being 1–2°C, and the tree

has no ability to acclimatize. Frost can severely damage or kill young trees,

with older trees being able to endure −4°C for a few hours with limited damage

(Crane and Campbell, 1991).

Fig. 10.2. Relationship between xylem water potential in the 6 weeks prior to ‘Nam

Dok Mai’ panicle growth and the percentage of terminals ﬂ owering: y = −121.83 –

286.7x, r

= 0.52 (Pongsonboon, 1991, cited by Schaffer et al., 1994).

256 Chapter 10

Temperature plays a key role in mango ﬂ owering, and the response varies

with cultivar. For ﬂ ower induction, the ideal seems to be around 10–15°C. The

cooler temperatures in the subtropics are normally followed by ﬂ owering, with

temperatures ~5°C inducing more male ﬂ owers on the inﬂ orescence. Panicle

growth does occur at 12.5°C, when no vegetative shoots are produced (Scha er

et al., 1994). However, low temperatures (<16°C) lead to ﬂ ower deformation,

loss of pollen germination (Fig. 10.3) and slow pollen-tube growth and induce

ovule abortion, with the production of seedless fruit (Young and Sauls, 1979).

For each 125 m increase in elevation and each degree of latitude north or

south of the equator, ﬂ owering is delayed by 4 days.

Light

Shading can prevent or delay ﬂ ower-bud formation, and a higher percentage

of perfect ﬂ owers occur on the side of the tree receiving direct sun. Mango

trees have a signiﬁ cant number of shaded leaves and pruning can increase

light penetration to these leaves, but how this inﬂ uences yield is unknown;

more light may result in larger fruit. Fruits also have a brighter red skin colour

under higher light (Scha er et al., 1994).

Photoperiod

Photoperiod seems to play no role in ﬂ ower induction (Nuñez Elisea and

Davenport, 1995). Flowering occurs at all photoperiods from 10 to 14 h at

an inductive temperature of 18°C day and 10°C night. The failure of biennial

cultivars to ﬂ ower in the ‘o season’ in the subtropics and ﬂ owering occurring

at the equator several times a year indicate a day-neutral habit.

Fig. 10.3. Effect of temperature during pollen development on mature pollen

viability (Issarakraisila et al., 1993).

Mango 257

WIND

Yield is reduced if strong winds occur during ﬂ owering and early fruiting;

however, the critical threshold for wind exposure is unknown. In windy areas,

windbreaks should be installed to improve yields and reduce fruit damage.

Dry winds during ﬂ owering in the subtropics can cause the loss of ﬂ owers,

and sometimes a second ﬂ owering will occur with better fruit set because

temperatures are more favourable (Galán Saúco, 2009)

GENERAL CHARACTERISTICS

Tree

The mango is an evergreen, symmetrical tree ranging in height from 8 to

30 m, bearing leathery, simple leaves in a compact canopy. The leaves are

alternate, elliptic or spear-shaped, spirally located and fairly leathery, and

10–40 cm long (Fig. 10.1). The leaves persist on the tree for up to 4–5 years

before being shed. Leaves of young ﬂ ushes are usually copper-red or purplish,

gradually turning to dark green.

Vegetative growth occurs in terminal ﬂ ushes of the same branch (Fig.

10.4); each ﬂ ush generates 10–12 new leaves with 1–3 ﬂ ushes a year. The

number, frequency and length of these ﬂ ushes per year depend upon cultivar,

temperature, tree age, current fruit load and previous cropping history. More

ﬂ ushes occur in the tropics than in the subtropics. The strong dominance of

the terminal bud prevents lateral buds from emerging. When shoot elongation

slows and stops, a state of dormancy occurs in the apex until the terminal

leaves have matured, and the shoot is then ready for the next vegetative

growth ﬂ ush or ﬂ owering. Reproductive ﬂ ushes will occur after extended

periods of shoot rest in the low-latitude tropics, aided by a dry period, or

during cool winter months in the higher-latitude tropics and subtropics (Fig.

10.4b) (Davenport, 2003). It is common to see di erent parts of a tree ﬂ ushing

at di erent times, especially in the hot tropics. Biennial or irregular ﬂ owering

has been observed in several cultivars in Hawaii; vegetative ﬂ ushes occurring

during the June–July period are more conducive to ﬂ owering the following

spring than ﬂ ushes that occur earlier or later (Nakasone et al., 1955).

The roots form a dense and strong system distributed in the ﬁ rst 2–2.5 m

and having a main tap root that can penetrate 6–8 m. If the water table rises,

a second root system will form above the main system.

Flowers

The induced reproductive terminal buds of the stem produce a large, branched

panicle (Fig. 10.1) with 300–3000 ﬂ owers, depending upon the cultivar. The

258 Chapter 10

ﬂ owers reach full bloom in as little as 25–30 days after initiation. The panicles

can be 6–40 cm long and 3–25 cm wide, with a pink or purple, sometimes

greenish-yellow, rachis. Surrounding the terminal bud are smaller buds (sub-

apical buds), which are morphologically lateral buds compressed into the

apical position, subtending the terminal bud. Apical dominance disappears

with the destruction of the apical inﬂ orescence (Nakasone et al., 1955).

The panicle consists of male (Fig 10.1a) and perfect hermaphrodite

ﬂ owers (Fig. 10.1b). Perfect ﬂ owers consist of four or ﬁ ve calyx lobes and as

many free petals (Fig. 10.1b). The centre of the ﬂ ower is occupied by a circular

disc (nectary) divided into four or ﬁ ve segments. The one-celled ovary with one

obliquely protruding stigma is attached to this disc. There is usually only one

functional stamen; the other four are reduced to abortive structures, called

staminodes. The male ﬂ ower (Fig 10.1a) is essentially the same, except for the

Flower

buds

(a)

(b)

Flower

buds

Flowering and

fruit set

Flowering and

fruit set

Fruit

growth

Fruit

growth

Vegetative

flush

Vegetative

flush

Root

flush

Root

flush

1234567

Month of cycle

Development Development

8 9 10 11 12 13

Fig. 10.4. Mango phenological cycle, having synchronous growth and ﬂ owering in

(a) the subtropics (after Cull, 1991), and (b) the tropics, with asynchronous growth

and ﬂ owering and a long juvenile phase (after Galán Saúco, 1996).

Mango 259

absence of an ovary. Petals are pinkish-white, with several yellow ridges on the

inner surface. The percentage of perfect ﬂ owers on a panicle ranges from 1.25

to 81%, with a strong varietal di erence in ﬂ ower-sex expression (Table 10.1).

The percentage of perfect ﬂ owers is higher in the apical zone of the panicle

than in the basal and central portions; climate can also a ect the percentage,

as can the position of the panicle in the canopy. Late-season panicles and

those formed in the interior of the tree usually have a larger number of perfect

ﬂ owers (Adlan, 1965). Flower and inﬂ orescence colour and ﬂ ower scent vary

among cultivars.

A good crop of fruit is obtained when only a small percentage of the

ﬂ owers are pollinated. Lack of fruit set is attributed to: (i) lack of fertile pollen;

(ii) poor pollen-tube growth; (iii) failure of ovule fertilization; (iv) failure of

pistil or ovules to develop; (v) abortions of embryo sac, embryo or endosperm;

(vi) anthracnose disease of the ﬂ owers; and (vii) other physical factors

(Scha er et al., 1994). Anthracnose disease is a major problem and is more

prevalent if rainfall occurs during ﬂ owering. The disease will eventually a ect

the whole panicle, leading to ﬂ ower and young fruit shed.

Pollination and fruit set

Natural pollination

About 65% of the ﬂ owers open before 6 a.m. and the rest open during the day.

Anther dehiscence occurs within an hour after anthesis, with a maximum

between 9 a.m. and noon. Eighty per cent of the pollen is viable (Fig. 10.3).

Stigmas are receptive from 1 day before anthesis until 2 days after, with the

day of anthesis being the optimum. Mango cultivars are considered to be self-

fertile, but self-incompatibility has been reported. Self-pollination produces

0–1.68% set, while cross-pollination produces 6.2–23.4%, but there are clear

cultivar di erences. The pollen grains fall on the base of the ovary and the

nectary discs rather than the stigma; hence pollination agents are required.

Insects, including bees, wasps and ﬂ ies, are the principal pollinating agents, as

indicated by the sticky pollen, secretion of nectar, colourful corolla and ﬂ ower

Table 10.1. Percentage of hermaphroditic and male ﬂ owers on three cultivars

grown in Hawaii (Adlan, 1965).

Sex Cultivar

Fairchild Zill No. 9 Total

Hermaphrodite 396 787 556 1739

Male 1660 1153 104 2917

Total 2056 1940 660 4656

% hermaphrodite 19.20 40.50 84.24

260 Chapter 10

scent. Flies seem to be the main pollination agents, with bees and other insects

contributing. Wind may play a small role. Pesticide use during ﬂ owering

a ects insect pollination, pollen germination and ovule fertilization.

Polyembryony

Subtropical Indian cultivars and their derivatives, characterized by roundish,

colourful fruit and susceptibility to anthracnose, are largely monoembryonic

(Fig. 10.5a). Cultivars classiﬁ ed in the Indochina–Philippine group from South-

east Asia are largely polyembryonic, relatively resistant to anthracnose and

often lack bright colour (Campbell, 1961). Polyembryony is the condition in

which several genetically identical embryos develop from the nucellar tissue of

the ovary and often suppress zygotic embryo development (Fig. 10.5b). These

polyembryous fruits are typically more elongated than round (Fig. 10.6).

(a) (b)

Fig. 10.5. Monoembryony (a) and polyembryony (b) in mango seedlings. In

polyembryony, several genetically identical embryos can be formed from the

nucellar tissue and often suppress the zygotic embryo.

Mango 261

Polyembryonic cultivars are generally believed to achieve higher fruit set,

since apomictic embryos take over the functions of the aborted zygotic embryos

and allow normal fruit development. Zygote abortion in monoembryonic

cultivars stops further fruit development and usually leads to fruit drop. A

small number of embryo-aborted fruit do develop into commercial-sized fruit.

Seedless fruit are reported in ‘Harders’, ‘Tommy Atkins’ and ‘Momi-K’ (Galán

Saúco, 1979), possibly due to embryo abortion taking place after growth-

promoting substances required for fruit development have been produced in

the endosperm.

Floral induction and fruit set

Biennial bearing and young fruit drop are major problems in commercial

mango production. Shoot biochemical constituents thought to be related to

ﬂ owering of regular- and irregular-bearing cultivars under di erent climatic

conditions are not consistent. This has led to much research on overcoming

the dependence upon environmental signals for ﬂ ower initiation using

di erent cultivars, using di erent management strategies and chemical sprays

(Table 10.2). This will be discussed in more detail under cultural practices.

Both the number of hermaphroditic ﬂ owers per panicle and the fruit-

bearing potential can be increased following application of 100 ppm of

Ventral

shoulder

(a) (b)

Ventral

shoulder

Dorsal

shoulder

Dorsal

shoulder

Dorsal

side

Axis

Length

stem to apex

Nak

Nak or

stigmatic point

Major

diameter

Major

diameter

Apex

Depression

about stem

Fig. 10.6. Morphological characteristics of the mango fruit (Pope, 1929).

Indochina–Philippine fruit are more elongated (a) and the Indian cultivars are more

rounded (b).

262 Chapter 10

Table 10.2. Chemicals for manipulating ﬂ owering or increasing fruit set and retention in mango (Galán Saúco, 1996).

Area Chemical Application time Dosage (foliar sprays) Action

Subtropics GA

Prior to ﬂ ower differentiation

(beginning of winter)

100 mg/l Delays ﬂ owering (repeated use

during winter will eliminate

ﬂ owering)

Cyclohexamide Flowering 0.25 g/l Destroys apical panicles

Dinoseb Flowering 0.5 ml/l Destroys apical panicles

Pentachlorophenol Flowering 5.0 g/l Destroys apical panicles

Ethephon Full-ﬂ ower stage 800 mg/l Destroys apical panicles

Hydrogen cyanide Beginning of ﬂ owering season 0.4% (cv. Haden)

0.6% (cv. Keitt)

Destroys apical panicles

Tropics NH

KNO

End of autumn 20 g/l

40 g/l

Interrupts ﬂ ower dormancy

Paclobutrazol Any time during fruit bud stage or

even at the end of autumn

2.5–5.0 g a.i./tree

(soil drench)

Reduction of vegetative growth and

ﬂ ower induction; increases fruit set

General Polyamines:

spermine

putrescine

KNO

Prior to anthesis or at full bloom

Full bloom

−1

−4

2–4%

Increase fruit set and fruit retention

Mango 263

naphthalene acetic acid (NAA) or deblossoming of terminal panicles either

manually or with chemicals. Both methods delay ﬂ owering and can increase

yield (Table 10.2). The stimulation of auxiliary panicles also occurs if

early panicles are damaged by low temperature or winds in the subtropics.

Sprays of GA can also delay ﬂ owering and fruit maturation by 2 weeks, but

concentration and timing of application are critical if yield is not to be reduced

(Turnball et al., 1996).

Fruit

Fruit morphology

The fruit of the mango is a drupe of variable size and shape, ranging in

weight from a few grams to more than 1 kg. It is ﬂ eshy, ﬂ attened, rounded

or elongated in shape. A number of basic forms of the major morphological

characteristics (Fig. 10.6) are used in describing the fruit (Pope, 1929).

Growth and development

Fruit growth showed a simple sigmoidal growth curve in terms of length,

thickness, mass and volume against days from anthesis (Fig. 10.7). The skin

200

160

120

Fruit mass (g) and starch (mg/g DM)

Acidity (%) and sugars (%)

Mass

Sugars

Starch

Acidity

20 40 60 80

Days from fruit set

100 120

Fig. 10.7. Changes in developing ‘Dashehari’ fruit weight, starch and total sugars

(after Tandon and Kalra, 1983) and ‘Nam Dok Mai’ titratable acidity (Kasantikul,

1983, cited by Mendoza and Wills, 1984).

264 Chapter 10

of the young fruit is green, sometimes purplish, and, when ripe, green, yellow,

orange, yellowish-red, purplish or purplish-red. The Indian group tends to

mature with a yellow-and-red colour combination, while the Indochina–

Philippine mangos have yellow- or orange-coloured fruit. Some fruits, such as

‘Nam Dok Mai’, have a slight pink hue on a yellow peel when ripe.

The peel (exocarp) is thick and the ﬂ esh (mesocarp) of ripe fruit is yellow

or orange-yellow and juicy. The pericarp can be separated into exocarp,

mesocarp and endocarp at about 14 days after anthesis. There is a period

9–14 weeks after fruit set when growth rate decreases, and this is associated

with hardening of the endocarp and accumulation of starch and sugars (Fig.

10.7). The endocarp is hard, with ﬁ bres that may extend into the ﬂ esh. The

period from fruit set to maturity depends upon cultivar and climate and can

range from 10 to 28 weeks. The cv. ‘Saigon’ grown in a hot climate is ready for

harvest in 12–13 weeks. In cool areas, where mean temperatures fall below

20°C, maturation is delayed by up to 4 weeks.

A network of latiferous canals and secretory ducts anastomoses in all

directions in the exocarp and mesocarp (Joel, 1978). Cultivars with a poorly

developed duct system are more susceptible to the Mediterranean fruit ﬂ y

(C. capitata Wied.). The latiferous canals in mango begin to disintegrate during

ripening and the fruit becomes susceptible to fruit ﬂ ies. The sap from the skin

contains urushiol, a toxin also found in other members of the Anacardiaceae,

which causes an allergic skin rash on contact. Urushiol is catechol substituted

with an alkyl chain with 15–17 carbon atoms. Some individuals are more

sensitive than others.

CULTIVAR DEVELOPMENT

Genetics, cytogenetics and breeding

Cytological studies of seven species, M. indica, M. sylvatica, Mangifera calo-

neura, M. zeylanica, M. caesia, M. foetida and M. odorata, showed all to have

a chromosome number of 2n = 40 (Mukherjee, 1950). M. zeylanica and

M. odorata have been successfully crossed, indicating the possibility of

interspeciﬁ c crosses without the problem of interspeciﬁ c sterility. This is

supported by the uniformity of chromosome morphology. Although mango

hybridization has been carried out, very few cultivars have been developed by

controlled pollination. Hence, little genetic information is available.

Problems in breeding

Breeding is di cult because of the small number of seeds obtained, the

complex nature of the panicle and ﬂ ower (Fig. 10.1a, b), excessive fruit drop,

Mango 265

long life cycle and heterozygosity of the crop (Knight and Schnell, 1993). The

objectives of mango breeding are to develop regular-bearing dwarf trees that

have an extended cropping season, good cropping in the wet tropics, attractive

fruit of good size (300–500 g), free from internal breakdown and good keeping

and eating quality without ﬁ bre. Active breeding programmes are carried out

in many countries in the world, including India, the USA, Israel and Australia

(Galán Saúco, 1996). Rating scales for important characteristics, such as size,

shape, colour, ﬁ rmness, ﬁ bre content, ﬂ avour, disease resistance and yield,

have been developed. Characteristics are rated on 1 to 5 or 1 to 10 scales (least

desirable to most desirable) in merely descriptive terms (Knight, 1985).

More recent objectives of mango improvement include resistance to

diseases, such as anthracnose and powdery mildew, both devastating to fruit

yields, and tolerance to environmental conditions such as soil salinity and

cold temperatures. There is some variation in the degree of fruit susceptibility

to anthracnose disease. Genetic transformation of mango is possible, using

Agrobacterium as the transformant.

Cultivars

There are hundreds of named mango cultivars throughout the tropics and

subtropics (Table 10.3). Each country or region also has their own selected

cultivars (Table 10.4). Preferences for cultivars vary in di erent regions of the

world. The most important commercial cultivars are derived from selections

among open-pollinated seedling populations. Many excellent cultivars have

been developed through introduction and selection by cooperation between

researchers, growers, nurserymen and hobbyists. Seedlings can be produced

by mass cross-pollination of a collection of mixed cultivars selected for known

desirable characteristics among mono- and polyembryonic races (Whiley et al.,

1993). Only seeds from the monoembryonic cultivars are used as the female

parent and planted for later evaluation. Polyembryonic lines are di cult to

use as the female parent, as there is no assurance that a sexual seedling will be

produced.

It is without doubt that India, with more than 1000 named cultivars and

with di erent regions growing speciﬁ c cultivars, has provided most of the

germplasm for cultivar development. Florida has developed a large number of

cultivars, using mainly Indian cultivars, which have shown wide geographic

adaptability. ‘Haden’ was a major cultivar in the early mango industry in

Florida. It may be a parent of other cultivars, including ‘Irwin’ and ‘Lippens’.

Other well-known Florida cultivars include ‘Keitt’, ‘Sensation’ and ‘Tommy

Atkins’ (Campbell and Campbell, 1992). Most mango varieties planted in the

Americas, the Canary Islands and many African countries were developed

in Florida. The Florida varieties are also dominant in international trade and

include ‘Tommy Atkins’, ‘Haden’, ‘Kent’, ‘Keitt’ and ‘Van Dyke’.

266 Chapter 10

Table 10.3. Some common mango cultivars grown commercially in different parts of the world.

Cultivar Origin

Poly/

Mono Fruit shape Skin colour

Fruit

maturation Fibre

Eating

quality Storage

Anthracnose

susceptibility

Alphonso India Mono Oblique Yellow Mid Low Excellent Low

Baptiste Haiti Poly Oval Bright yellow Mid None Fair to good

Carabao Philippines Poly Long and

slender

Greenish to bright

yellow

Early None Good to

excellent

Poor Low

Haden Mulgoba,

India

Mono Oval Red blush or

yellow

Mid Abundant Good to

excellent

Susceptible

Irwin Lippens,

Haden

Mono Ovate Red Mid None Good Poor Low

Keitt Mulgoba Mono Oval Red blush on

green

Late Little Good to

excellent

Good Moderate

Kensington Australia Poly Oblong ovate Yellow with pink

blush

Mid Low Excellent Low

Langna India Mono Oblong Pink blush or

greenish-yellow

Mid Abundant Fair to good

Manila Philippines Poly Long and

slender

Bright yellow Mid Fibrous Good to very

good

Mulgoba India Mono Oval to ovate Yellow with pink

blush

Mid to late Little Good to

excellent

Very

susceptible

Nam Dok

Mai

Thailand Poly Long slender Bright yellow Mid None Excellent Susceptible

Neelum India Mono Ovate Bright yellow Late None Good to

excellent

Mango 267

Pairi India Mono Round to

oblong

Orange-red Mid Little Good Moderate

Saigon Vietnam Poly Oval to ovate Yellow None Good to

excellent

Low

Tommy

Atkins

Haden Mono Oval to

oblong

Dark red or orange-

yellow

Mid Moderate Fair Good Resistant

Tong Dam Thailand Poly Oblong to

long

Greenish-yellow Early None Good to

excellent

Susceptible

Zill Haden Mono Oval to

ovate

Dark red to crimson

or yellow

Mid None Good to

excellent

Poor Susceptible

268 Chapter 10

In Mexico, the ‘Manila’ and ‘Ataulfo’ varieties of Philippine origin are

grown, while in Brazil, in addition to the main export varieties (Table 10.4),

local varieties from material introduced by the Portuguese are also produced.

In most of Latin America, di erent ‘criollo’ mango varieties are grown, which

belong to the Indochina–Philippine group. These criollo types have survived

as such since they are polyembryonic and almost exclusively propagated

by seeds.

In the last few years some new varieties have been demanded by the US

market, the largest import market, and also by the EU; these include ‘Edward’,

a Florida variety, ‘Ataulfo’, a polyembryonic variety from Mexico, and others,

such as ‘Madame Francis’ from Haiti and ‘Julie’ from Jamaica and the

Caribbean. The EU is also starting to import other varieties such as ‘Amelie’

from Africa and ‘Nam Dok Mai’ from Thailand.

Hawaiian cultivars, such as ‘Pope’, ‘Gouveia’, ‘Momi-K’, ‘Ah Ping’,

‘Harders’ and ‘Joe Welch’, are all derived from monoembryonic parents. The

recently released improved cultivars are ‘Rapoza’ and ‘Exel’, the former being

a seedling of ‘Irwin’ and having large fruit with excellent eating quality;

Table 10.4. Producing countries, selected cultivars and main marketing season.

Country Selected cultivar Marketing season

Australia Kensington Pride, Keitt, Kent, Palmer,

Irwin

October to March

Brazil Haden, Tommy Atkins, Kent, Keitt, Palmer,

Bourbon, Espada, Itamarco, Maco, Rosa,

Carlota

October to February

India Alphonso, Banganpalli, Dashehari,

Bangalora, Langra, Mulgoa, Neelum,

Pairi

April to July

Indonesia Arumanis, Dodol, Gedong, Golek,

Cengkir

September to January

Israel Keitt, Tommy Atkins, Kent, Maya, Haden July to August

Malaysia Harumanis, Golek, Maha 65, MA 200

(Malgoa)

June to August

Mexico Haden, Manila, Esmeralda, Kent, Keitt,

Tommy Atkins, Jan Dyke, Palmer

April to October

Peru Kent, Tommy Atkins, Haden November to February

Philippines Carabao, Pico, Julie June to September

South Africa Peach, Zill, Fascell, Sensation, Tommy

Atkins, Keitt

November to January

Spain Tommy Atkins, Keitt, Lippens, Osteen July to August

Taiwan Irwin, Yellow #1, Haden July to October

Thailand Nam Dok Mai, Rad, Tongdum, Okrong March to May

USA – Florida Keitt, Irwin, Tommy Atkins, Kent, Van

Dyke, Palmer

July to August

Mango 269

it is a late bearer, with fruit maturing from August through October, greatly

extending the season (Hamilton et al., 1992). ‘Exel’ was also selected from a

population of ‘Irwin’ seedlings for its high quality, attractive fruit and regular-

bearing habits, with fruit weight ranging from 400 to 500 g and with 18%

total soluble solids. Another desirable feature of the fruit is the thin, ﬂ at seed,

which results in more than 90% edible ﬂ esh (Ito et al., 1992).

Isozyme analysis has been used to verify or refute parentage of mango

cultivars (Degani et al., 1990). Isozymic banding has shown that ‘Haden’

appears to be a seedling of ‘Mulgoba’, and ‘Zill’ a seedling of ‘Haden’.

‘Mulgoba’ has the ab phenotype and ‘Keitt’ the cc phenotype, while ‘Haden’

shows an aa phenotype, ‘Carabao’ bb and ‘Edward’ ac. Newer molecular-

biology techniques are being used to unscramble the parentage of mangoes

and to determine the extent of genetic diversity (Krishna and Singh, 2007).

Rootstocks

Most mango plants are grafted on to polyembryonic rootstocks in order

to obtain plants that have a uniform root system, since they come from

an asexual process and so are clones. There are several rootstocks in each

country. In Latin America, some of the ‘criollo’ types of the Indochina–

Philippine group are used; however, not all are good rootstock. In Mexico,

the cultivar ‘Manila’ (‘Carabao’), which is exported and consumed locally,

is used. Israel has developed ‘13-1’ for saline and alkaline conditions. South

Africa uses ‘Sabre’ for sandy soils and ‘4/9’ for heavy soils. In the Canary

Islands ‘Gomera-1’ and in mainland Spain ‘Gomera-3’ are used (Galán Saúco,

2009). Australia uses the polyembryonic ‘Kensington Pride’, which is also a

commercial fruit cultivar. Very little has been reported about the inﬂ uence of

rootstock on the cultivar growth.

The Indian cultivars ‘Olour’, ‘Vellai Colamban’ and ‘Saber’ are used as

rootstocks to reduce tree vigour. Researchers have sought rootstocks with

special attributes, such as dwarﬁ ng habit and tolerance to high pH and saline

conditions. Two Indian hybrid cultivars, ‘Mallika’ (‘Neelum’ × ‘Dashehari’)

and ‘Amrapali’ (‘Dashehari’ × ‘Neelum’), have been reported to exhibit distinctly

dwarﬁ sh characteristics in terms of trunk circumference, tree height and canopy

diameter in Brazil (Pinto and Sharma, 1984). Tolerance to saline soils has been

identiﬁ ed, and cultivar ‘13-1’ is being used commercially as a rootstock in Israel,

where calcareous soil and saline irrigation water pose serious problems (Gazit

and Kadman, 1980).

270 Chapter 10

CULTURAL PRACTICES

Propagation

Sexual

Mango seeds should be planted while still fresh, as they lose their viability

within a few weeks. The usual procedure is to eliminate the pulp from around

the seed by fermentation and washing, and superﬁ cially dry the seed in the

shade for a couple of days. Uniform germination can be achieved if the kernel

is removed from the hard endocarp or seed coat; this can be achieved by

using pruning shears to cut the edges and remove the seed. During sowing,

the concave part of the seed should face down and be buried about 4–5 cm

into sand or a sandy mix. This sandy medium allows easy extraction of the

seedlings with little damage to the roots when repotted. The germinated

seedlings are separated and transplanted singly into polyethylene bags (18 cm

(w) × 13 cm (d) × 30 cm (h)), and bags up to 45 cm in height help to avoid

early root deformation. The seedlings are grown under ~30% shade. The seeds

of polyembryonic cultivar produce several seedlings, some of which become

twisted together and have curved stems and roots, and should be discarded

and not transplanted into nursery bags. Monoembryonic seeds from breeding

programmes can be planted directly into the polyethylene bags. Polyembryonic

cultivars, though they can be propagated by seed as they retain the parental

characteristics, are grafted to take advantage of the earlier production and

shorter, stockier trees, avoiding the juvenile characteristics of seedling trees.

Asexual

Cultivars are propagated vegetatively by such methods as cuttings, grafting,

budding or air-layering. Cutting propagation has been successfully achieved

using hardwood or semi-hardwood cuttings, or subterminal cuttings with

adult leaves being put under mist and bottom heat, and the cut surface treated

with auxin (Reuveni et al., 1991). This method is justiﬁ ed in cases of a scarcity

of monoembryonic rootstock material.

Seedlings can be grafted in 6–8 months if fertilized and irrigated regularly.

Grafting is usually some form of side or cleft graft, with the side-wedge method

also being frequently used. Splice grafting is occasionally used. Only a well-

matured terminal and the section below it should be used as scion wood,

immature wood often fails to graft. Terminal scions are preferred because

they will have no wound at the apex end of the scion piece. Budding methods

permit the use of much younger rootstocks. Buds may be prepared in advance

by removing the leaves of mature terminal wood. Removal of the leaves and

the apical bud destroys apical dominance and allows axillary buds to begin

to swell in 1–2 weeks. Air-layering and inarching are used in some areas to

generate experimental plants rapidly. However, these time-consuming methods

are appropriate when only a few plants are needed. Cultivars propagated by

Mango 271

grafting and inarching grow faster than those propagated by stooling and air-

layering. Grafting at a low height produces a spreading tree, while grafting

high up on the stock produces a non-spreading type.

Field preparation

Land preparation is similar to that with other tree crops. Deep ripping may be

necessary to break up any hard subsoil layer. In some cases sulfur has to be

added if the soil is too alkaline. This is also the time when organic matter can

be added without interference from the tree canopy.

Transplanting and spacing

Transplanting should be done just before or early in the wet season if no

irrigation is available. Often, organic matter and P fertilizer are added to the

planting hole (0.5 m × 0.5 m × 0.5 m) before planting. No shade is required

after transplanting. Spacing is largely dependent upon environment, soil

characteristics, vigour of the cultivar and the planned orchard management.

Various patterns, with spacing from 6 m × 3 m to 7 m × 15 m, are recom-

mended. High-density planting (3 m × 2.5 m) has been tested with grafted

trees, and, while individual tree yields are low, total yield is higher, although

extensive pruning is essential (Ram and Sirohi, 1991). In the subtropics, closer

spacing (6 m × 4 m or 6 m × 3 m) is being used, with more detailed formation

pruning and annual maintenance pruning to prevent the trees from becoming

too large.

Irrigation

Young transplants require about 20–30 l of water every 4–5 days for about

2–3 months during establishment. For the remainder of the ﬁ rst year, rates

may be increased to 40–50 l at 7–10-day intervals. During the second year,

rates are increased to about 100–150 l per 10 days. More may be necessary

during particularly dry periods. In the third year, rates of 200–300 l/tree at

15-day intervals may be adequate. Rates may be decreased or increased and

the intervals shortened or lengthened, in accordance with soil type and the

amounts and periods of rainfall.

Four- to 5-year-old grafted trees can begin to bear fruit, and cultural

practices should be adjusted to reﬂ ect this change. For bearing trees,

especially in the tropics, it is desirable to have a 3–4-month dry period prior

to ﬂ owering, to reduce vegetative ﬂ ush growth. This is easily accomplished in

areas where this period coincides with the natural dry period. In dry areas,

272 Chapter 10

irrigation is desirable after the inﬂ orescence appears and as ﬂ owers begin to

set fruit. During the ﬁ rst 4–6 weeks of fruit development, cell division is most

rapid and moisture stress should be avoided. Four-year-old trees may require

around 400–500 l water/tree at 2-week intervals. Irrigation is completely cut

o as the fruits approach maturity, since dry conditions favour higher sugar

content. Heavy irrigation is resumed immediately after harvest to encourage

new vegetative growth (Fig. 10.4). In the monsoon tropics, termination of

harvest coincides with the rainy season, so irrigation is usually unnecessary.

As soon as a major vegetative ﬂ ush occurs, reduction in soil moisture content

is desirable to mature the new ﬂ ush. The choice of irrigation equipment and its

management is based on capacity and e ciency of water delivery, and cost of

the system plus installation. Irrigation should be programmed in accordance

with the phenological growth cycle (Fig. 10.4) to achieve maximum yield.

Pruning

In most subtropical areas, the tendency is to use narrower plant spacings

and keep the trees small by pruning. In the hot tropics, the trees are also kept

smaller than before by pruning, but they are normally larger than in the

subtropics.

Formation pruning can start in the nursery, at transplanting time or

shortly after transplanting. All lateral shoots from the main stem are removed

until the plants reach a height of 70–100 cm, to train the tree to a single

trunk. For varieties with long hanging branches, at this height the top 10–20

cm is cut o below a node. In the subtropics this should not be done in autumn

or winter, otherwise ﬂ oral shoots might develop (Galán Saúco, 2009). Later

lateral buds will sprout and three well-oriented and well-distanced shoots are

left to become the primary tree branches. These shoots should be oriented in

di erent directions, hopefully separated by a 120° angle; at the same time

there should be a distance of 20–30 cm between them along the main stem, so

that the weight of the adult tree is not concentrated at one point. For varieties

that tend to produce very long shoots at a narrow angle, the selected primary

branches can be forced to grow at a 45° angle. This forcing will slow their

growth and induce more laterals to arise and reduce excessive tree height.

To obtain compact trees for narrow plant spacing, once the main lateral

branches have stopped growing and mature, the terminal buds are pinched

o , with as few leaves as possible being removed. From these pinched main

lateral branches, three shoots are left to grow, and they will be pinched the

same way, so that nine secondary branches are formed, and ﬁ nally these can

also be pinched, leaving three equally spaced new shoots on them, completing

a total of 27 tertiary branches. This process is repeated during the ﬁ rst 2–3

years until a well-balanced plant is obtained.

Mango 273

When less-compact canopies are desired, pinching can be done every

second or third ﬂ ush, and later the canopies are opened at the centre by

removing interior branches, so that the plant and fruit receive more light.

In some tropical areas topping of the vegetative shoots at the second or

ﬁ rst internode is done to obtain more-compact trees (Galán Saúco, 2009).

Pruning can also be done to accommodate the trees for espaliers and trellises,

where pinching is done at the height of the ﬁ rst wire so that two new shoots

are directed along the wire and the third shoot grows up to the second wire,

and repeated.

After the trees have been adequately trained, annual pruning is not

usually practised. Mango trees normally make very dense growth, and

occasionally light thinning of branches will become necessary to facilitate

light penetration, air movement, pesticide penetration, removal of dead and

diseased branches and some control over tree height. The tallest branches

are cut back at the fork (point of origin) of the branch. ‘Water sprouts’ and

overlapping branches may be removed annually. In Florida, pruning is done

with machines called ‘ledgers’ and ‘toppers’ by cutting back the height and

width of the trees to about 4 m. This is done annually immediately after

harvest (Campbell, 1988). These trees have two or three vegetative ﬂ ushes

before becoming dormant at the onset of winter and then produce ﬂ owers in

the following spring.

Pruning becomes a major endeavour when trees are allowed to outgrow

the space provided. Yields are reduced and harvesting becomes di cult

and uneconomical. Removal of alternate trees appears only to aggravate

management problems later, as remaining trees will grow even larger. Drastic

pruning of large trees to about 2 m to develop new tops on old trunks may

cause approximately 3 years’ loss of income. Yearly pruning to less than ~3 m

to control tree height is practised in Taiwan, without signiﬁ cant impact on

year-to-year production. The fruits are bagged to reduce disease and insect

damage, and fruits thinned to match fruit load to tree size (Fig. 10.8).

In cultivars with biennial (irregular) ﬂ owering, shoots that have ﬂ owered

are removed after harvest, leaving only shoots that may ﬂ ower next time.

Flowering shoots that do not set fruit should also be removed soon after

ﬂ owering. Removal of apical buds after each ﬂ ushing cycle to increase the

number of terminal shoots that could ﬂ ower can lead to better fruiting and

limits tree size (Oosthuyse and Jacobs, 1995). The number of terminal shoots,

however, is not always related to the number of fruit set (Fig. 10.9). There is

a strong correlation between number of terminal shoots and fruit number

for the cv. ‘Sensation’, which retains a higher number of fruit per shoot than

‘Kent’, indicating that other factors are involved. Deblossoming of the terminal

inﬂ orescences can lead to inﬂ orescence development from axillary buds, a

20–30-day-later harvest and higher yields (Chang and Lion, 1987).

In the lower tropics, where ﬂ owering time is modiﬁ ed, synchronization

pruning is done every year to force the trees to produce new shoots at the

274 Chapter 10

same time. For this, peripheral pruning is done all over the canopy, removing

the tips of the last growth, including leftover ﬂ oral peduncles, which have

an inhibitory e ect on future ﬂ owering. This pruning will force the tree to

produce new growth, simultaneously resulting in more uniform ﬂ owering,

since all new shoots are of the same age and in a similar physiological stage.

This pruning should be rather light to avoid a strong tendency to get a second

vegetative ﬂ ush too soon, since this would not allow enough time for the shoot

to rest and become reproductive. It is done soon after harvest, and it is the ﬁ rst

step in the process of ﬂ ower induction.

Fertilization

One of the basic considerations for fertilization amount and time of

application is the growth and ﬂ owering cycle of the tree (Fig. 10.4). During the

ﬁ rst 3 years, approximately 113–227 g per tree of a complete (NPK) fertilizer

is applied three times a year. From the fourth year, trees are considered to

be mature, as they will begin to produce commercial yields, and fertilizer is

applied twice a year. One application is made when the ﬁ rst inﬂ orescence

begins to appear and the second immediately after harvest, to promote a new

vegetative ﬂ ush. Proper placement is important in ground application, as the

highest feeder-root density is approximately 90–175 cm away from the trunk

to a depth of 20 cm. Irrigation is necessary whenever fertilizer is applied.

The major mango-growing countries have usually developed their own

fertilizer ratios and amount to be applied. Complete fertilizers, with an oxide

ratio of approximately 15:15:15, are usually recommended in Hawaii (Yee,

1958). In Florida, a good crop can be obtained by providing 1.4–1.8 kg of N

and K/tree/year to mature trees (Malo, 1976). Using the triple-15 fertilizer,

(a) (b)

Fig. 10.8. Mango tree showing profuse and uniform ﬂ owering (a). Trees are

managed to less than 2 m. When the fruits are about 7 cm across, the tree is sprayed

with fungicide to control fruit diseases, the fruits are thinned and the selected fruits

are bagged (b). One fruit has 6–8 leaves subtending it on the branch.

Mango 275

an application of 4 kg/tree in February–March provides 0.6 kg each of N

and K. A second application immediately after harvest of 6 kg/tree provides

0.9 kg each of N and K, for a total of 1.5 kg each of N and K for the year. N

and K at these levels are reported to enhance total yields, external colour and

sugar content, while N in excess of 1.8 kg can produce unfavourable e ects

on external colour and ﬂ esh ﬁ rmness (Young and Koo, 1974). When leaf N

levels are greater than 1.5%, reduced fruit size is expected, with an increased

incidence of ‘soft nose’ and soft brown rot and an increase in the number of

days to ripen. Critical levels for various nutrients in mango leaves have been

developed (see Table 4.3).

Flowering synchronization and induction

Ethephon, an ethylene-releasing compound, increases ﬂ owering and fruiting

in ‘o ’ years in biennial-bearing trees. In the past, to produce ﬂ oral induction,

Philippine farmers used smudging by burning rice straw close to the trees, with

the smoke having a stimulating e ect on mango ﬂ owering. This was possibly

due to the ethylene gas in the smoke. In the last two decades more sophisticated

approaches have been developed and are being used commercially.

In the subtropics, ﬂ owering depends on the cool winter temperatures (Fig.

10.4a) and ﬂ owering is enhanced by water stress. In cool winters, the plants

will ﬂ ower profusely (Fig. 10.8a). For young plants, this profuse ﬂ owering

can limit plant growth and the ability to achieve the desired tree size, so the

Fig. 10.9. Relationship between the number of terminal shoots on 2-year-old

‘Sensation’ and ‘Kent’ trees and number of fruit retained. ‘Sensation’ y = 0.98x +

12.8, r

= 0.86***, ‘Kent’ y = 0.18x + 11.8, r

= 0.31* (after Oosthuyse and Jacobs,

1995).

276 Chapter 10

ﬂ owers and small fruit are removed during the ﬁ rst few years to allow the

plants to become larger. In the tropics, ﬂ ower induction is not dependent on

a cool winter and is regulated by the time since the last ﬂ ush matured after

the sprouting induced by the synchronized peripheral pruning. If this shoot

sprouts too soon, then the new ﬂ ush will be vegetative; if the apex has rested

for a longer period, a reproductive apex will form. The length of the rest period

varies with variety.

The main aim of mango producers in the northern hemisphere is to

harvest in March to April when prices are highest. In Central America, normal

ﬂ owering occurs in January/February and the harvest then coincides with

that of Mexico. Mexico, as the largest world exporter and main supplier to

the USA, makes it di cult for other supplies to compete, and prices are low

because of oversupply. Other northern-hemisphere suppliers use orchard

management practices to induce earlier ﬂ owering and harvest 1–3 months

earlier to coincide with the better market prices. This is possible as a major

portion of Mexican mango production occurs under subtropical conditions

in northern Mexico and they are unable to signiﬁ cantly modify the ﬂ owering

time. Similar procedures are followed in other parts of the world in order to

achieve better economic returns by harvesting before the bulk of production

arrives to the market. During ‘El Niño’ years, when winter temperatures are

higher, Peruvian and Ecuadorean mango production is a ected, though little

can be done to overcome the poor ﬂ ower induction.

For these orchard management practices to work e ectively to advance the

ﬂ owering date, the following factors should be taken into account: (i) the plant

leaf N concentration should be between 1.1 and 1.3% at the time of induction;

higher concentrations result in vegetative shoots; (ii) the soil moisture

content should not be low, in order to achieve a better reproductive response;

this is di cult to control in the tropics if the induction time occurs during

the rainy season; (iii) the age and maturity of shoots, with older shoots that

have been inactive after vegetative growth and maturation being more likely

to di erentiate into a reproductive shoot. To limit vegetative growth an anti-

gibberellin compound such as paclobutrazol is used. Low soil nitrogen and

moisture also play a role in reducing the occurrence of early vegetative ﬂ ush;

and (iv) the e ectiveness of the application of ﬂ owering stimulants, where the

dosage, the tree coverage, age and state of the leaves and the time the product

stays on the leaves inﬂ uence the outcome (Huete and Arias, 2007).

Steps to induce ﬂ owering

Stimulation of new shoots

The primary goal is to stimulate abundant vegetative shoot production. This

is achieved by: (i) synchronizing peripheral pruning after harvest, which will

result in a uniform synchronous production of new vegetative shoots at the

Mango 277

same physiological age. This pruning should also remove all of the last season’s

panicles, which inhibit future ﬂ owering. This pruning should not be extensive;

(ii) a balanced fertilization programme that ensures good vegetative growth

but does not provide excessive amounts of nitrogen, or lead to a deﬁ ciency;

and (iii) soil moisture management that involves limiting irrigation as the

leaves approach maturity to prevent the potential for premature shooting.

CHECKING VEGETATIVE GROWTH

Limiting vegetative growth can be achieved with paclobutrazol and

uniconazole, the latter being ten times more potent. These products are

expensive, sometimes di cult to ﬁ nd in most countries and if used improperly

can cause permanent tree damage. These anti-gibberellin compounds inhibit

sprouting and reduce the time needed between synchronization pruning

and ﬂ oral stimulation by about 1 month. These inhibitors are applied 1–2

months after harvest, when the shoots from the synchronization pruning

have completed their growth phase. Paclobutrazol can be applied at a rate of

5–8 g/plant

or 1 g/m of canopy diameter, while uniconazole is applied at a

rate of 0.1 g/m

of the canopy shade. The application is made in 10–20 l of

water put in a shallow trench at the canopy drip line; the soil should be moist

before application and irrigated after, to carry the chemicals to the root zone.

Another anti-gibberellin product, ‘Pix’ (mepiquat chloride), is sprayed at 1%

active ingredient on to the canopy until run o . A 2–3 cm girdle can induce

ﬂ owering but often leads to the death of ~5% of branches per year and is not

recommended. Controlled scoring is now used on subterminal branches with

little danger of tree damage. Controlling water stress is di cult in the tropics

with frequent rain, except in tropical deserts.

Spraying ﬂ owering stimulants

Flowering can also be inﬂ uenced by nitrates, such as potassium nitrate at

2–4%, calcium nitrate at 1–3% and ammonium nitrate at 1–2% sprayed

on trees in the tropics, but apparently not in the subtropics. One to three

additional sprays of the same chemicals can be done at weekly intervals if

the e ect is not satisfactory. Thiourea can be used instead of nitrates. Young

shoots (1.25 months from bud emergence) of the Philippine cvs ‘Carabao’

and ‘Pahutan’ can be induced to ﬂ ower uniformly by spraying 10 and 40 g/l

of KNO

, respectively. ‘Carabao’ ﬂ owered in 11 days, while ‘Pahutan’ required

20 days. Spraying older ‘Carabao’ shoots (8.5 months from bud emergence)

with 10–160 g/l KNO

induced 100% ﬂ owering, with unsprayed controls

remaining vegetative (Bondad and Apostol, 1979). Genetic di erences among

seedling trees and between cultivars means that variations in response to the

chemical used occur, with the nitrate ion being the e ective ion (Nagao and

Nishina, 1993).

Eight factors will determine the success of these nitrate sprays: (i) the

leaves have to be mature, dark green and brittle when squeezed; (ii) the

278 Chapter 10

nitrogen concentration of the leaves should be less than 1.3%; (iii) soil

moisture should be low; (iv) application at night when cool and days are warm

or after a cold front; (v) rain should not occur for at least 6 h after spraying

to avoid the product being washed o ; (vi) the whole tree should be sprayed to

runo ; this can take 8–20 l/tree. A spreader sticker improves the e ectiveness

of the sprays; (vii) the best time to apply is after 4 p.m.; and (viii) the variety

should be responsive. The Indochina–Philippine varieties respond readily to

stimulation, while Indian variety ‘Haden’ responds better than ‘Kent’ or ‘Keitt’,

and ‘Tommy Atkins’ is the least responsive. Advancing ﬂ owering date should

be done in several small steps (Duarte, 2002) to avoid losing production. In

the ﬁ rst year, ﬂ owering is brought forward 20 or 30 days, with a similar step

in the following year, until the desired ﬂ owering date is achieved. Following

application, ﬂ owering will occur in about 3 weeks.

Nitrates or other products do not induce or change apex di erentiation:

if it is a vegetative apex, a vegetative shoot will sprout; if it is a reproductive

structure, a ﬂ ower panicle will emerge; nitrates induce the bud to start

growing. The factor that determines whether a shoot apex produces a ﬂ ower

panicle or a vegetative shoot is the age of the shoot from the time it started

to grow after the synchronizing pruning. The older the shoot, the greater the

possibility that a ﬂ ower panicle will emerge. Normally ‘Haden’ shoots can be

sprayed 4 months after synchronization pruning, while ‘Tommy Atkins’ needs

5 months for similar results. Davenport (1993) proposed the following model

for mango ﬂ owering induction in the hot tropics:

With paclobutrazol application:

Harvest − pruning + 1 month, paclobutrazol + 3 months = 4 months to

induce ‘Haden’

Harvest − pruning + 2 months, paclobutrazol + 3 months = 5 months to

induce ‘Tommy Atkins’

Without paclobutrazol application:

Harvest − pruning + 5 months to induce ‘Haden’

Harvest − pruning + 6 months to induce ‘Tommy Atkins’

The paclobutrazol treatment reduces by 1 month the time that the shoot

needs to be in a non-active stage to ﬂ ower after nitrate application in the

tropics. The result is explained by postulating that gibberellins are ﬂ ower-

formation inhibitors. Paclobutrazol and uniconazole have not been labelled for

use on fruit crops in the USA, though they are not translocated into the fruit.

Fruit yields

Fruit yields vary with cultivar, climatic and edaphic conditions of the

production site, cultural practices and other factors, such as diseases and

Mango 279

insect pests. Yields over many years exhibit a sigmoidal curve, initially with

low yields, increasing more rapidly and then dropping o as trees become

crowded. The period of maximum production depends upon tree growth rate;

a rapidly growing cultivar is more likely to show decreasing yields earlier, due

to crowding. Mango yield studies over a su cient number of years involving

replicated plantings are relatively rare, due to time and cost.

In Puerto Rico, researchers determined yield potential, year-to-year

consistency of production, estimates of incremental increase in yields over age

of trees, fruit size and tree growth of 16 cultivars in their ﬁ rst 6 crop years.

The adjusted cultivar mean yield can be separated into three yield groups,

with no signiﬁ cant di erences between cultivars within each group (Pennock

et al., 1972). The high-yielding group order was ‘Ruby’, ‘Sensation’, ‘Eldon’.

‘Lippens’ and ‘Irwin’; an intermediate group ‘Earlygold’, ‘Keitt’, ‘Parvin’,

‘Zill’, ‘Haden’ and ‘Palmer’; and a low-yield group of ‘Pillsbury’, ‘Kent’,

‘Edward’, ‘Santaella’ and ‘Jacquelin’. Cultivar consistency of bearing also

gave three di erent groupings, having di erent cultivar make-up: ‘Edward’,

‘Zill’, ‘Pillsbury’, ‘Ruby’, ‘Lippens’ and ‘Irwin’ as regular bearers; ‘Sensation’,

‘Santaella’, ‘Parvin’, ‘Earlygold’ and ‘Jacquelin’ with intermediate consistency;

and ‘Kent’, ‘Eldon’, ‘Palmer’, ‘Haden’ and ‘Keitt’ being highly inconsistent

in yield (Fig. 10.10). The consistent-bearing cultivars with high yields were

‘Ruby’, ‘Lippens’ and ‘Irwin’. ‘Edward’, ‘Zill’ and ‘Pillsbury’ show regular-

bearing habit but consistently produce low yields.

A mango orchard on the south coast of Puerto Rico under similar

conditions to those of the above experimental site began production about 5

Fig. 10.10. Year-to-year variation in yield of three cultivars having different bearing

habits (Pennock et al., 1972).

280 Chapter 10

years after ﬁ eld planting. The ﬁ rst crop had around 2.3 kg/tree, increasing to

about 12.7 kg/tree/year during the next 5 years. On a per-hectare basis, with

173 trees/ha (57.8 m

spacing), the initial yield of 5-year-old trees would be

393 kg/ha, with a yearly increase of 2.2 t/ha

(Pennock et al., 1972). Yields

obtained in Florida, Mexico, and Central and South America have shown

that in the ﬁ fth year after planting, 0.9 t/ha can be expected, increasing to

1.7 t/ha in year 6, 3.5 t/ha in year 7, 5.2 t/ha in year 8 and 8.7 t/ha in year

9. Mature trees can yield 10–30 t/ha, with an average of 22–25 t/ha in the

subtropics. In the tropics, commercial yields of 10 t/ha are expected from

high-quality cultivars.

PEST MANAGEMENT

Diseases

Anthracnose (C. gloeosporioides) is perhaps the most important disease

of the mango in almost all production areas (Table 10.5), as it attacks

leaves, ﬂ owering panicles and fruit. Yields are drastically reduced when

the inﬂ orescence is attacked. This disease is especially serious in areas with

high humidity and frequent light showers during the ﬂ owering period. In

Hawaii, where rainfall coincides with the ﬂ owering season, almost the entire

production of inﬂ orescences can be destroyed. In the Ryukyu Islands of Japan

(26°N), a crop of mango can be produced only by constructing polyethylene

shelters over the trees to protect the inﬂ orescence from the frequent light

showers falling during the ﬂ owering season. For this reason, trees are kept

at 1.8–2.4 m in height. In Australia, the cultivars ‘Carabao’, ‘Keitt’, ‘Tommy

Atkins’ and ‘Zill’ have been identiﬁ ed as possessing tolerance to anthracnose

(Whiley and Saranah, 1981). Control measures include weekly sprayings of

the plants during ﬂ owering, alternating a systemic fungicide with a protectant;

spraying during the coolest hours of the day and applying a protectant as soon

as a noticeable weather change occurs are also recommended. Cleaning the

orchard ﬂ oor by picking old leaves and fallen fruit, as well as weed control, will

also help to reduce the inoculum levels.

Powdery mildew (Oidium mangiferae) attacks leaves, stems and

inﬂ orescences and is a common disease of the dry subtropics, and it can also

become serious, especially under drier conditions (Johnson and Coates, 1993).

Normally, the treatments to control anthracnose also control both fungi, and

treatment is necessary until the fruit reaches the size of a cherry.

A disease that has been reported from a number of areas and is very

serious in India, Pakistan and Egypt is mango inﬂ orescence malformation.

Malformation occurs on vegetative shoots and ﬂ owering panicles. Panicles

become short, branchy and compacted and produce solely male ﬂ owers

(Shawky et al., 1980). Lower temperatures during panicle development are

Mango 281

Table 10.5. Some important diseases, disorders and conditions of mango.

Common name Organism Parts affected, symptoms Region or country

Anthracnose

Colletotrichum

gloeosporioides

Inﬂ orescence; leaf black spots, lesions on

fruit

Universal

Powdery mildew

Oidium mangiferae

Leaves, inﬂ orescence; whitish-grey

powdery spores

Universal

Mango scab

Elsinoe mangiferae

Blossoms, leaves, twigs, fruit; greyish-

brown spore masses, cracked tissues

Widespread

Bacterial black spot

Xanthomonas campestris

Leaves, stem and fruit; small watery lesions

that coalesce, causing necrotic spots 2–3

mm diameter with irregular borders

Subtropical cold areas

Inﬂ orescence malformation

Fusarium moniliforme

Inﬂ orescence compact, sex shift to

maleness; no fruit set; vegetative shoot

compact with small leaves

Egypt, India, Pakistan, Africa,

Americas

Stem-end rot

Diplodia natalensis,

Fusarium, Alternaria,

Cladosporium

Fruit; blackening of stem-end of fruit, skin

and pulp, over-mature fruit; rotting

Widespread

Sooty mould (not pathogenic)

Capnodium sp.,

Meliola sp.

Leaves, stem, fruit; sooty black appearance;

symptom of scale insects, mites and

mango hopper damage

Universal

Internal breakdown (jellyseed;

soft-nose)

Unknown Fruit; pulp breakdown Florida

Some similarity in symptoms; further studies required for clariﬁ cation.

282 Chapter 10

associated with a higher incidence. It is caused by Fusarium moniliforme, with

mites playing a minor role. A highly signiﬁ cant reduction in malformation is

achieved, with an increase in yield, by spraying with GA

and NAA, singly and

in mixtures, with a second application 2 weeks later. Pruning all malformed

vegetative and ﬂ oral ﬂ ushes, followed by spraying with copper oxychloride

(4 g/l), is more e ective than pruning alone to reduce the percentage

of malformed panicles and increases the yield in the following season

(Azzouz et al., 1989).

Two other diseases with unidentiﬁ ed causes can sometimes cause

serious loss, although little is reported in the literature. The ﬁ rst a ects the

bark at the base of the trunk, with increased gummosis on the upper trunk

and large limbs. Wilting of branches occurs, followed by death, particularly

to trees around 8 years old. It is especially serious in Nayarit and Sinaloa

States in Mexico and has been reported from Colima State in Mexico and

from Guatemala. Both Fusarium and Phytophthora are suspected but have

not been conﬁ rmed. The other condition is a disease of the fruit, with no

puncture wounds or insects being observed. The external symptom is a

black spot 0.5–1.5 cm in diameter, usually located at the nak of the fruit.

When the blackened area is cut, there is a hollow ‘tunnel’ leading to the seed

cavity. The seed and seed cavity are blackened. When the fruit is cut open,

many show the peduncular vascular system leading to the endocarp to be

disintegrated (Nakasone, 1979). It was observed to be extremely serious in

orchards of ‘Tommy Atkins’ in Nayarit and on ‘Kent’ in Campeche, Mexico,

and subsequently reported to occur in the Canary Islands and in Guatemala,

where it is called ‘pepita negra’. Lakshminarayana et al. (1985) reported a

similar preharvest stem-end disease of ‘Tommy Atkins’ in Mexico, except that

no mention was made of the black spot on the nak of the fruit. Preliminary

studies isolated a mixture of six species of Fusarium and produced more

diseased fruit with typical symptoms than any other single isolate. Bacterial

black spot (Xanthomonas campestris) of the mango appears to be a relatively

serious disease in South Africa and Australia. It has also been seen in

Hainan, China.

Insect pests

Mediterranean and Oriental fruit ﬂ ies are spread widely throughout the world.

Other ﬂ ies are conﬁ ned to speciﬁ c regions, but together they constitute a

major problem, particularly to the export trade (Table 10.6). Irradiation, hot

water and vapour heat treatment have been developed to meet disinfestation

requirements in importing countries. This is probably the most important

pest of mango, since the presence of a larval form in the fruit renders it non-

exportable to many countries. Exports are generally allowed to countries

where the winters are very cold and the ﬂ ies do not survive. The female ﬂ ies lay

Mango 283

their eggs in the developing fruit as it starts to ripen. Larvae produced by these

eggs feed on the pulp and move through the fruit, causing premature ripening,

rotting and fruit drop. The larvae eventually leave the fruit and bury into the

ground to become pupae; this phase lasts until the adults emerge, and the cycle

is repeated. Control measures include early harvest to shorten exposure time,

eliminating other host plants, collecting and burying fallen fruit, and the use

of traps to monitor adult populations. The release of sterile males can be very

useful in isolated areas or valleys or islands where in-migration of new ﬂ ies is

di cult. Chemical control based on Malathion and hydrolysed protein bait is

also used. Bagging is used in some countries (Fig. 10.8b); though expensive

it results in fruit without ﬂ y injury, very little or no anthracnose, better colour

and about 95% of the harvested fruit is saleable.

The mango seed weevil has been a major deterrent to mango export

to some countries. The weevil is an Old World pest, but is found now in

some parts of the New World: St Lucia, Guadeloupe and Martinique in the

Caribbean region (Pollard and Alleyne, 1986). Field sanitation, chemical

sprays, host-plant resistance, pest-free zones, fruit culling, using X-ray

technology and irradiation are possible solutions to this problem, unless

markets are found in temperate countries that do not require disinfestation. All

cultivars are susceptible, with some cultivars showing lower seed infestations

of 17% to a high of 86%. The weevil deposits its eggs on the surface in the

sinus region of small green fruit in the lower 2 m of the tree. Upon hatching,

the larva burrows through the soft pulp into the seed, goes through the pupal

stages feeding on the developing seed and then ﬁ nally develops into an adult

weevil. When the fruit ripens and pulp decomposes, the adult beetles bore their

way out of the endocarp and enter diapause in cracks and crevices on the tree

until the next season. Since there is no external evidence of infestation and

the fruit normally remains edible, the consumer is unaware of their presence.

The weevil can a ect the appearance of the ﬂ esh if the mature weevil burrows

out, causing decay, which hastens ripening and may even cause premature

fruit drop.

The mango hopper is a serious pest in India, the Philippines and some

other areas. The hopper sucks the sap from ﬂ owering stems, causing them

to wilt. In serious cases, most of the panicles are damaged. Mango ﬂ owers

are destroyed by four mango blossom midge species and others attack the

leaves (Table 10.6). One of these midges is a serious pest of mango ﬂ owers

throughout the state of Hawaii, with several cultivars having 91% of the buds

infested, leading to perfect-ﬂ ower abortion. Eradication by chemical sprays is

not feasible, due to the wide distribution and the large size of the trees, and

biological control is not an alternative as no predators have been reported in

the native habitats.

In Central America, cutting ants (Atta) can be a serious problem,

especially for young plants because they can completely defoliate the tree.

Control can include surrounding plants with an old tyre split in half and

284 Chapter 10

Table 10.6. Some important insect pests of mango.

Common name Organism Parts affected, symptoms Region or country

Mexican fruit ﬂ y

Anastrepha ludens

Larval damage to fruit Caribbean

South American fruit ﬂ y

Anastrepha fraterculus

Larval damage to fruit Americas

Caribbean fruit ﬂ y

Anastrepha suspensa

Larval damage to fruit Caribbean, Florida

Queensland fruit ﬂ y

Batrocera tryoni

Larval damage to fruit Australia

Mediterranean fruit ﬂ y

Ceratitis capitata

Larval damage to fruit Widespread

Marula fruit ﬂ y

Ceratitis cosyra

Larval damage to fruit Africa

Natal fruit ﬂ y

Ceratitis rosa

Larval damage to fruit Africa

Oriental fruit ﬂ y

Dacus dorsalis

Larval damage to fruit Asia, Hawaii, Philippines

Mango seed weevil

Sternochetus mangiferae

Seed India, Hawaii, Philippines,

S. Africa, South-east Asia,

Oceania, Caribbean

Mango blossom midge

Erosomyia indica

Dasineura mangifera

Sucking sap from ﬂ oral parts India, Hawaii

Mango hopper

Idioscopus sp.

Sucking sap from ﬂ owering shoots Philippines, India, Africa,

Oceania, Americas

Red-banded thrips

Selenothrips rubrocinctus

Sucking on underside of young leaves Widespread

Coconut bug

Pseudotheraptus wayi

Sucking sap from young fruit, watery spot

on fruit, fruit drop

Africa

Mango 285

half-ﬁ lling this with water. Baits of chlorpyrifos insecticide used as pellets put

on the ant trails or at the entrance of their nest are used. The ants take the

pellets down the nest and as they come in contact with the fungus they feed

on they die. Another way is to pump chlorpyrifos powder into the nest with

a special blower; this will kill all ants if the product reaches all corners of the

nest.

Other insect pests, such as scale insects, thrips and the red spider mites are

found almost universally but they are relatively easily controlled by natural

enemies and by chemical sprays and do not usually pose any problems.

Weed management

Weed control is essential during orchard establishment. Young trees can be

grown under clean cultivation or sod. Frequently intercropping is practised

during mango establishment with papaya, pineapple or vegetables. Canopy

closure of maturing trees prevents weed growth.

HARVESTING AND POSTHARVEST HANDLING

Harvesting

Harvest maturity is determined by using criteria such as changes in colour,

fullness of cheeks and hardened endocarp. The most reliable indicator of

maturity is when the endocarp has hardened and there is a yellowing of the

ﬂ esh near the seed; however, this is a destructive test. Immature fruit do not

ripen to full ﬂ avour and should not be harvested, hence the importance of

maturity determination. Fruit-set dates can be established as an index for

harvesting. The fruit-set date for each tree is determined when the panicle

shows a high percentage of initial fruit set. An old recommendation to judge

the date of harvest was when the ﬁ rst fruit dropped, the fruits on the tree were

ready to pick. The mango is harvested by hand from the ground, wherever

reachable, or from ladders and by the use of a long pole with a metal basket

or a cloth bag to hold two or three large fruit. Harvesting is also done using

two people, one on a ladder to cut the fruit and let it drop into the hands of the

other on the ground.

Postharvest treatments

Any form of bruising should be avoided during harvesting and transporting to

the packing house. Normally the fruit will be harvested with a 3–4 cm length

of peduncle; the fruit are put under the shade of the trees either on the ground

in small furrows or on a layer of sawdust or in specially designed boxes with

286 Chapter 10

the cut part of the peduncle pointing down for about 30 min until the sap

ﬂ ow stops. In Australia, ‘Kensington Pride’ fruits are washed in the ﬁ eld. The

use of shallow lug boxes minimizes bruising. At the packing house, fruits are

usually placed in a water bath or hand-washed to remove the stem sap from

the surface, and the peduncle is cut according to speciﬁ cations. Sap removal

is essential to prevent sap burn and should be done within 24 h (Lovey et al.,

1992). Fruit anthracnose can be controlled by dipping into hot water (52°C,

5 min). A combination of hot water and a fungicide or chlorine may also be

used. When the fungicide is added to the hot water, the temperature can be

reduced slightly (Akamine, 1976).

Grade standards are usually based upon size, colour and freedom from

injury and defects. Other requirements include full development, freedom from

stains and ﬁ rmness. Since the fruit is easily bruised, fruits are packed in single-

or double-layer cartons with adequate protective material or use of trays.

The US box contains about 4.5 kg and the EU box 5 kg. In the local markets,

mangoes are frequently packed in bamboo baskets or in wooden crates.

At ambient temperatures, shelf-life of this climacteric fruit is short: 7–14

days to fully ripe. Precooling to 10–13°C is beneﬁ cial during hot weather or

when shipping is delayed. Fully ripe fruit can be stored at 8–10°C. The length

of shelf-life varies markedly with cultivar, maturity at harvest, injury, calcium

(Ca) sprays and exposure to ethylene. A dip in 4–6% calcium chloride can

signiﬁ cantly increase shelf-life of some cultivars, with the response varying

with season, ﬁ eld management practices and soil type. Fruit of ‘Keitt’, ‘Tommy

Atkins’ and ‘Muska’ from successive harvests show an increasing rate of

ripening changes during the 21 days’ storage period at 12°C, suggesting a

decrease in storage potential as the season progressed.

Mango is a climacteric fruit and ethylene can be used to reduce the time till

ripening commences. A treatment of 100 ppm for 24–48 h at 25°C and 90%

relative humidity (RH) is adequate. Acetylene generated from calcium carbide

and ethephon can also be used. Skin colour is also enhanced by ethylene

treatment by increasing degreening. The best ripening temperature range is

from 21 to 24°C. At high temperatures of 32°C, ripening can be retarded.

Controlled atmospheres have been tested on mangoes and indicate some

possibilities; storage in atmospheres of 5% oxygen (O

) and 5% carbon dioxide

(CO

) is possible for 20 days, while o -ﬂ avours and skin discoloration occur at

1% O

or high CO

(15%). Cultivar di erences in response have been reported

and the extension in shelf-life may not be commercially viable. Controlled

atmosphere for ripe fruit is ine ective. Containers with controlled atmospheres

are available for transport. Modiﬁ ed atmosphere storage using plastic bags

or wraps and waxing shows some delay in ripening. O -ﬂ avours have been

reported with some wraps and waxes that delay ripening. Waxes are widely

and successfully used commercially on mango to reduce water loss.

Postharvest disorders include chilling injury, sap burn, internal

breakdown and bumpy tissue (Wainwright and Burbage, 1989). Chilling

Mango 287

injury is a storage disorder that occurs at temperatures below 12.5°C, the

extent of the injury being dependent upon the storage temperature and

duration: at 0°C injury occurs in 4 days, at 5°C in 8 days and at 10°C in 12

days. The symptoms include skin scald, failure to ripen and increased disease

susceptibility.

Sap burn caused by fruit skin contact with sap exuded from the cut or

broken pedicel reduces consumer acceptance because of the browning and

blackening of the skin after lenticel penetration. The Australian cultivar

‘Kensington’ is very susceptible (Lovey et al., 1992), while ‘Irwin’ is less

susceptible. The sap component in ‘Kensington’ thought to cause the burn

is the major non-aqueous terpene component, terpinolene; it can also burn

‘Irwin’, but in ‘Irwin’ the predominant terpene (6.8%) is car-3-ene. This sap

is present in the latiferous ducts of the fruit and is not interconnected with the

stem ducts. The latex is under some pressure and when the pedicel is broken

can shoot 300 mm or more. Harvesting with the stem attached, draining with

the pedicel down and washing are e ective.

One fruit disorder, occurring especially in ‘Alphonso’ in India, is referred

to as ‘internal breakdown’, ‘spongy tissue’ or ‘soft tissue’. The lower half of the

fruit is most a ected and it may be related to preharvest heat stress. ‘Soft nose’

in Florida is serious, with high Ca inhibiting the disorder and high N increasing

the disorder (Malo and Campbell, 1978). The ‘jelly-seed’ disorder is more

widespread. The disease usually appears during the initial stages of maturity,

with a loss of ﬁ rmness of the pulp near the endocarp, which becomes jelly-like

and translucent with advancing ripeness. The disorder does not develop after

harvest. An open cavity may develop in the pulp at the stem end prior to pulp

breakdown. ‘Tommy Atkins’ has been reported to be especially susceptible to

this disorder, although ‘Kent’, ‘Irwin’, ‘Sensation’, ‘Carabao’, ‘Alohouron’ and

a few other commercial cultivars of importance are also susceptible (Campbell,

1988). No pathogenic organism has been detected. The only recourse for this

disorder is to harvest the fruit at the mature-green stage, before any colour

break occurs on the skin.

Certain cultivars are particularly susceptible to lumpy tissue, which is not

evident in green fruit but develops during ripening. The mesocarp contains

white starchy lumps and the fruit surface develops indentations. Aetiology is

unknown. It has been reported from Thailand and the Philippines. Internal

fruit necrosis ﬁ rst appears as a brown area in the mesocarp and endocarp

of rapidly growing fruit. This later extends to the skin and a brown-black

gummy exudation occurs. These areas then collapse and are surrounded

by corky tissue. This non-pathological disorder has been associated with

boron deﬁ ciency.

288 Chapter 10

Marketing

Consumer preferences vary, with the US market apparently preferring large-

sized and highly coloured mango without the turpentine taste, colour being

the more important. Mango marketing has taken on international dimensions,

with major marketing centres around the world. Canada and the USA are

the major markets in North America, while the major European Union (EU)

markets are located in the UK, France, Germany and the Netherlands. In the

Far East, Japan, Hong Kong and Singapore are lucrative markets for producing

countries such as the Philippines, Malaysia, Thailand and Pakistan. The

Philippine and Mexican mangoes dominate the Japanese market. The major

supplier for Hong Kong is the Philippines.

Countries supplying the North American and European markets are

Mexico, Ecuador, Brazil, Peru, Venezuela, Haiti, Jamaica and other Caribbean-

island countries in the Americas, and Ivory Coast, South Africa and Mali in

Africa. Egypt and Israel are small producers but are looking at the EU market

windows. Increases in demand will largely depend upon increasing consumer

familiarity with the fruit, quality and price structure. By virtue of geographical

location in the southern hemisphere, South Africa, Brazil, Peru and Australia

are able to supply mangoes to the North American, European and Asian

markets during their winter months, thus making mango a fruit that is

available year-round (Table 10.4).

UTILIZATION

The mango is rapidly becoming one of the leading trade crops in the tropics

and subtropics. As postharvest handling techniques and shipping technology

have improved, consumer demand has increased. The fruit is 60–75% ﬂ esh,

11–18% skin and 14–22% seed, depending upon cultivar, with the ﬂ esh

being ca. 20% dry matter. Most of the mangoes produced are marketed in the

fresh state for consumption as a dessert fruit. Fruit can be eaten green, and

this practice is very popular in Thailand, the Philippines and Central America,

with some starchy and crispy cultivars being preferred, such as ‘Khieo

Sawoey’ in Thailand. Fruit may simply be peeled and sliced. Diced pieces

may be added to salads and fruit cocktails. People consume mango simply

because of its pleasant taste and ﬂ avour without much thought about the

content of minerals, vitamins, lipids and amino acids. However, the mango is

a good to excellent source of provitamin A and is considered a fair source of

vitamin C (Table 10.7), although this varies greatly among cultivars, with a

range between a low of 5 mg and as high as 142 mg/100 g of fresh material

(Wenkam, 1990).

Mango 289

A considerable amount of fruit is processed into various products, such

as jellies, jams, marmalades, pulp, juice and canned slices, throughout the

world. Green mangoes make excellent chutney and are being exported for

raw consumption by Latin American and other ethnic groups in the USA and

Canada. Canned mango slices have been processed in India since before 1925

(Hayes, 1966). Canned mango and dehydrated slices are important export

products in the Philippines and some other countries.

Table 10.7. Nutritive values of mango in a 100g edible portion (Wenkam, 1990).

Nutrient Units Haden Pirie

Proximate

Water g 84.12 79.97

Energy kcal

234

301

Protein g 0.39 0.55

Lipids (fat) g 0.02 0.20

Carbohydrate g 15.05 18.91

Fibre g 0.54 0.70

Ash g 0.42 0.37

Minerals

Calcium mg 8 6

Iron mg 0.16 0.16

Magnesium mg 12 12

Phosphorus mg 10 15

Potassium mg 159 126

Sodium mg 0 3

Zinc mg – –

Copper mg – –

Manganese mg – –

Vitamins

Ascorbic acid mg 15.10 15.00

Thiamin mg 0.041 0.081

Riboﬂ avin mg 0.057 0.061

Niacin mg 0.300 0.460

Pantothenic acid mg – –

Vitamin A RE

381

3813

474

4735

Vitamin B6 mg – –

Vitamin B12 mcg – –

290 Chapter 10

FURTHER READING

Cull, B.W. (1991) Mangos crop management. Acta Horticulturae 291, 154–173.

Johnson, G.I. and Coates, L.M. (1993) Postharvest diseases of mango. Postharvest News

and Information 4, 27N–34N.

Litz, R.E. (ed.) (1997) The Mango: Botany, Production and Uses. CAB International,

Wallingford, UK.

Mendoza, D.B. and Wills, R.B.H. (eds) (1984) Mango: Fruit Development. Postharvest

Physiology and Marketing in ASEAN. ASEAN Food Handling Bureau, Kuala Lumpur,

Malaysia.

Ridgeway, E. (ed.) (1989) Mango Pests and Disorders: Information Series QI890O7.

Queensland Department of Primary Industries, Brisbane, Australia.

Scha er, B., Whiley, A.W. and Crane, J.H. (1994) Mango. In: Scha er, B. and Andersen,

E.C. (eds) Handbook of Environmental Physiology of Fruit Crops. Vol. II. Subtropical and

Tropical Crops. CRC Press, Boca Raton, Florida, pp. 165–197.

Wainwright, H. and Burbage, M.B. (1989) Physiological disorders in mango (Mangifera

indica L.) fruit. Journal of Horticultural Science 64, 125–135.

(R.E. Paull and O. Duarte)

PAPAYA

Papaya (Carica papaya L.) is a popular fruit native to tropical America. It

is usually grown for its small to large melon-like fruit. It is a herbaceous

perennial, bearing fruit continuously at the leaf axils spirally arranged along

the single erect trunk. The papaya is also called papaw, pawpaw, papayer

(French), melonenbaum (German), lechosa (Spanish), mamao, mamoeiro

(Portuguese), mugua (Chinese) and betik (Malaysian, Indonesian).

BOTANY

Taxonomy and nomenclature

The cultivated papaya belongs to the family Caricaceae and is the only member

of the genus Carica. Caricaceae is a small family of dicotyledonous plants

with six genera; four of tropical American origin (Carica, Jarilla, Jacaratia,

Vasconcella) and one, Cylicomorpha, from equatorial Africa. Caricaceae species

have been variously classiﬁ ed in families such as Cucurbitaceae, Passiﬂ oraceae,

Bixaceae and Papayaceae. Approximately 71 species have been described,

though Badillo (1993, 2000) reduced the number to 32 species, with the

following distribution: Carica, 1 species, Cylicomorpha, 2 species, Jacaratia,

5 species, Jarilla, 3 species, Vasconcella, 20 species, and Horovitzia, 1 species.

Papaya (C. papaya L.) is the most important economic species in Caricaceae.

Carica and Vasconcella species are dioecious, except for the monoecious

Vasconcella monoica (Desf.) and some Vasconcella pubescens and the polygamous

C. papaya. Most species are herbaceous, single-stemmed and erect. Other than

C. papaya L., the other edible species are Vasconcella candamarcensis Hook. f.,

V. monoica Desf., Vasconcella erythrocarpa Heilborn, Vasconcella goudotiana Solms-

Laubach and Vasconcella quercifolia Benth. and Hook (Storey, 1969). These fruit

are mostly eaten cooked, being normally dry and lacking the juicy ﬂ esh of C.

papaya. Another edible species, Vasconcella pentagona, is called ‘babaco’.

292 Chapter 11

Origin and distribution

C. papaya has not been found wild in nature and is only distantly related to

the Vasconcella species, based upon isozyme and AFLP analysis. The greatest

diversity in C. papaya exists in the Yucatan–San Ignacio–Peter–Rio Motagua

area of Central America. The volunteer population in this area has greater

diversity than domesticated populations (Morshidi, 1996; Van Droogenbroeck

et al., 2002). Papaya origins are rather uncertain, but there is some agreement

among botanists that it originated in the lowlands of Central America, between

southern Mexico and Nicaragua. Early distribution over a wide geographical

region in Central and South America was aided by the abundance of seeds in

the fruit and the seeds long viability. The accounts of 18th-century travellers

and botanists indicated that seeds of papaya had been taken from the

Caribbean to Malacca and on to India (Storey, 1941a). From Malacca or the

Philippines, distribution continued throughout Asia and to the South Paciﬁ c

region. Don Francisco Marín, a Spanish explorer and horticulturist, is credited

with the introduction of papaya into Hawaii from the Marquesas Islands

during the early 1800s. Papaya is now grown in all tropical countries and in

many subtropical regions of the world (Anonymous, 2003).

ECOLOGICAL REQUIREMENTS

Major commercial production of papaya is found primarily between 23° N and

S latitudes. Man has extended cultivation into regions as far as 32° N and S.

At these latitudes, papayas may be best grown in well-protected areas at sea

level. In Hawaii, at l9–22° N, papaya is grown at sea level and up to 300 m

elevation.

Soil

Papaya can be grown on a variety of soil types, with the most essential

requirement being drainage. A porous loam or sandy loam soil is preferred.

In Hawaii, the crop is frequently grown on rocky, volcanic soil called a’a,

composed of porous lava with some organic matter and excellent drainage;

the planting holes are ﬁ lled with soil prior to planting.

Soil pH should be between 5.0 and 7.0, with the range between 5.5 and

6.5 being more desirable (Awada et al., 1975). At pH levels below 5.0, seedling

growth is poor and mortality high. In soils with a pH range of 5.0–5.5, lime

applications can increase growth and yield. Papaya can be grown successfully

on problem soils. For peat soils, high rates of lime application (6–8 t/ha) are

essential for cultivation. Micronutrients (boron, zinc and copper) are also

applied to ensure production of high-quality fruit on these soils. Since the

Papaya 293

water table is usually high in peat soils and other alluvial soils along streams

and canals, drainage is required. A major constraint is the tendency for trees

to lodge in these soils, especially for heavy bearers, because of poor anchorage

and limited root growth once fruiting commences. Cultivation of papaya on

sandy soils requires the incorporation of large amounts of organic matter

and heavy fertilization (8 kg/plant/year) coupled with irrigation. Boron

deﬁ ciency and nematode infestations are two major problems encountered

on sandy soils. On acid-sulfate soils, which are compact, acidic, contain toxic

concentrations of certain micronutrients and prone to ﬂ ooding, papayas have

a relatively short economic life. This short lifespan is due to a poorly developed

root system and extreme susceptibility to root and collar rot diseases under

poor drainage conditions. Similarly, heavy clay soils should be avoided due to

the poor drainage.

Climate

Rainfall

Papayas grow well and produce substantial yields without supplementary

irrigation if there is a minimum monthly precipitation of approximately

100 mm. Since most tropical areas have monsoon-type climates with

well-deﬁ ned wet and dry seasons, successful production depends upon the

availability of supplemental irrigation during the dry period.

A minimum relative humidity of 66% has been reported for papaya’s

optimum growth. Stomatal opening is controlled by humidity and, as relative

leaf water content is not a ected by drought stress, stomatal closure maintains

leaf water status, allowing rapid return of gas exchange ﬂ ux and growth upon

rewatering (Marler, 1994; Clemente and Marler, 1996). Drought frequently

leads to the rapid shedding of new ﬂ owers and older leaves, and poor fruit

set. Five days of ﬂ ooding leads to abscission of fully developed leaves which

is preceded by chlorosis. Flooding frequently leads to plant death, due to root

rots, while recovery from non-lethal ﬂ ooding is slow, due possibly to the low

root growth rate of fruiting trees.

Papaya has been ranked from extremely sensitive to moderately tolerant to

salt stress. Germination and early seedling growth are the most sensitive stages

to salt stress. It is probably moderately salt sensitive at other growth stages.

Temperature

Optimum temperature for growth is between 21 and 33°C; if the temperature

falls below 12–14°C for several hours at night, growth and production are

severely a ected (Lange, 1961). Dioecious cultivars are better suited to low

temperatures (<20°C), as female trees do not exhibit stamen carpellody shown

by the more temperature-sensitive bisexual (hermaphroditic) cultivars (Fig.

11.1). Hermaphroditic cultivars (Solo type) grown at minimum temperature

294 Chapter 11

<17°C can have 100% carpellodic ﬂ owers. At higher temperatures (>35°C),

bisexual cultivars often become functionally male, with poorly developed and

non-functional female parts. This tendency varies with cultivars and within a

cultivar. Net photosynthetic rate also rapidly declines above 30°C.

Temperature during the growing season signiﬁ cantly inﬂ uences fruit

growth and development from the normal 120–150 days (Fig. 11.2). The

e ect is most pronounced in subtropical areas. In these areas, fruit set does not

normally occur in winter, and fruit set before the winter can take up to 90 days

longer to reach maturity. Final fruit size is determined in the ﬁ rst 4–6 weeks

of fruit development, and temperature plays a dominant role in the process,

especially in subtropical areas. Fruits that develop in the cooler season have

lower total soluble solids and ﬁ nal fruit size.

Radiation

Papaya in its wild state is found developing as a rapid volunteer in areas

where the tree vegetation has been disturbed. The high saturation point above

1000 μmoles/m

/s (photosynthetic photon ﬂ ux) (ca. 800 W m

-2

) supports its

rapid development in areas having direct sunlight in newly disturbed areas.

No photoperiodic e ects on tree growth, production or sex expression have

been reported (Lange, 1961). When exposed to shade, the plant is shorter,

Fig. 11.1. The percentage of true hermaphrodite, hermaphrodite with functional

stamens (male), and non-functional pistil and carpellodic ﬂ owers at different times

of the year, on ‘Solo’-type papaya tree growing in Honolulu with a mean minimum

temperature of 21°C and maximum temperature of 27°C (Awada, 1958).

Papaya 295

having smaller leaf area, lower stomatal density, increased internode and

petiole length and increased chlorophyll content, and hence is regarded as a

shade-avoiding species. Partial stomatal closure and opening occur rapidly

with cloud-related changes in irradiance, maximizing water-use e ciency.

Windbreaks

Papaya trees are delicate and require protection from strong winds. When

the root system is well developed, though relatively shallow, the tree can be

uprooted by winds of 64 km/h, especially if the soil is softened by rain. Even

though trees can withstand uprooting, loss of leaf area leads to ﬂ ower and

young fruit abscission, and low total soluble solids in the more mature fruit

on the column. Full recovery from wind damage to the leaves can take from

4 to 8 weeks.

GENERAL CHARACTERISTICS

Stem

The papaya is a large, monoaxial herbaceous plant with an erect stem

terminating with a crown of large leaves and can attain heights of 7–9 m

Fig. 11.2. The effect of date of fruit set on ﬁ nal fruit size and days from anthesis to

the half-ripe stage of plants grown under subtropical conditions (Kuhne and Allan,

1970).

296 Chapter 11

(Fig. 11.3). Although there are occasional lines or cultivars that produce an

abundance of lateral branches, especially during the juvenile period, the main

stem normally grows without branching, unless the growing point is injured.

Natural growth of the axillary branches does occur when the trees become

3–5 years old. The stem is semi-woody and hollow and a major site of starch

storage. The bark is smooth, greyish in colour, with large, prominent leaf

scars. When the stem is wounded, a thin milky sap oozes from the wound.

After transplanting, shoot growth is initially slow, though considerable

root growth is taking place, extending out well beyond the canopy drip line.

Stem growth is then rapid up to ﬂ owering, increasing in circumference up

to 2 mm per day. Growth rate peaks at ﬂ owering then declines as the tree

starts bearing (Fig. 11.4). The rate of growth is inﬂ uenced by nitrogen and

phosphorus supply, irrigation and temperature.

Leaves

A cluster of leaves occurs at the apex of the plant and along the upper part

of the stem and makes up the foliage of the tree. New leaves are constantly

formed at the apex and old leaves senesce and fall. Leaves are palmately lobed

with prominent veination and can measure 40–50 cm or more in diameter

and have an individual leaf area of 1625 cm

, with ca 15 mature leaves per

plant (Fig. 11.5). In the tropics, new leaves appear at a rate of two to three

a week (Chan and Toh, 1984); in Hawaii the rate is 2.4 per week during the

cool season and up to 3.0 in the warm season. Petioles are cylindrical, hollow

and 60–90 cm long, depending upon the cultivar. The most recently matured

leaf’s fresh weight (~10th leaf from 2.4 cm juvenile leaf) can vary from ca 50

to 170 g. The leaf petiole dry mass increases at a rapid rate until ﬂ owering

then increases more slowly, peaking after fruit bearing starts (Fig. 11.5).

Inﬂ orescence and ﬂ owers

There are three primary groups of ﬂ owers, i.e. pistillate, staminate and

hermaphrodite, with many variants, especially in the hermaphrodite group

(Fig. 11.3). Flowers are borne on modiﬁ ed cymose inﬂ orescences that appear

in the axils of the leaves. The type of inﬂ orescence depends upon the sex of

the tree. The pistillate tree produces only pistillate ﬂ owers on short, 4–6 cm

peduncles, with a functional pistil devoid of stamens (Fig. 11.3a). The ﬁ ve

petals are separate but are inconspicuously fused together at the very base of

the ovary. In staminate trees, ﬂ owers are sessile and are produced in clusters

on long, pendulant racemes 60–90 cm long. The individual ﬂ ower is tubular

with ten stamens in two series of ﬁ ve, attached to the throat of the corolla

tube, and lacks an ovary. The hermaphroditic form (Fig. 11.3b) is between the

Papaya 297

Fig. 11.3. Papaya leaf, female (a), hermaphrodite (b) and male ﬂ ower (c) types, and

fruit.

298 Chapter 11

two unisexual ﬂ ower types and exhibits numerous deviations. The basic ﬂ ower

on a short peduncle is characterized by an elongated pistil with ﬁ ve stigmatic

rays and ﬁ ve petals that are fused to about two-thirds of their length, forming

a corolla tube. There are ten stamens in two series of ﬁ ve attached to the

throat of the corolla tube. The pistil is normally ﬁ ve-carpellate and elongated,

oval or pyriform.

Taking into account the numerous deviations, Storey (1941b) classiﬁ ed

papaya ﬂ owers into ﬁ ve basic types (Table 11.1). Type I: pistillate or female

ﬂ ower devoid of stamens, with a distinct ovoid ovary terminating in a ﬁ ve-

lobed stigma (Fig. 11.3a). Type II: hermaphrodite (pentandria) ﬂ ower having

ﬁ ve functional stamens and a globose ﬁ ve-furrowed ovary (Fig. 11.3b).

Type III: hermaphrodite (carpelloid) ﬂ ower having six to nine functional

stamens and an irregularly ridged ovary. Type IV: hermaphrodite (elongata)

ﬂ ower having ten functional stamens and an elongate, smooth ovary. Type

IV+: hermaphrodite (barren) ﬂ ower having ten functional stamens but

the pistil aborts, becomes vestigial and lacks a stigma (Fig. 11.3c). Type V:

staminate ﬂ ower having ten functional stamens only. The ovary is completely

absent and ﬂ owers are bunched in an inﬂ orescence. Although ﬁ ve basic

ﬂ oral types are listed, certain male and hermaphrodite trees undergo sex

Fig. 11.4. The growth rate of papaya root and stem in the ﬁ eld, showing root growth

rate reduction at the start of ﬂ owering and shoot growth as fruits start to develop

(after Marler and Discekici, 1997).

Papaya 299

reversal and morphological changes in various degrees under the inﬂ uence

of environmental changes (Storey, 1958). Type V staminate ﬂ owers may

form functional ovaries and bear fruit during cool months. Type III ﬂ owers

can form carpelloid fruit when exposed to low temperatures about 40 days

before anthesis.

The appearance of a large number of modiﬁ ed ﬂ ower forms occurs in

progenies from appropriate hybridization when grown under a temperature

regime that may range from around 13 to 32°C. Therefore, recovery of

extreme sex modiﬁ cations may not be seen in a breeding programme unless

conducted in an area with wide ﬂ uctuations in seasonal temperatures in

highly heterozygous parental types. Stamen carpellody is expressed under cool

temperatures, with increasing severity as temperatures lower in the ca 40 days

before anthesis (Fig. 11.1). Instead of ten stamens in a double whorl, there are

only ﬁ ve stamens, with the other ﬁ ve ﬁ xed to the normal carpels. The fruits

that develop from this carpellody are severely misshaped and unmarketable

(Fig. 11.6). Female sterility occurs under warm temperatures, again with

increasing severity at higher temperatures in the ca. 40 days before anthesis.

Excessive nitrogen and moisture also favour stamen carpellody, while plant

stress such as N deﬁ ciency and moisture stress inﬂ uences female sterility

(Awada and Ikeda, 1957).

Fig. 11.5. Growth rate of papaya stem circumference, dry weight of the most

recently matured leaf petiole and the 17th leaf from the 2.4 cm juvenile leaf under

dry land conditions of Puna, Hawaii. The dry weight reduction in April is attributed

to low rainfall in the previous 2 months (Awada, 1977).

300 Chapter 11

Table 11.1. Types of papaya ﬂ owers (Storey, 1958).

Types Tree

Flower

Description

Staminate M M Typical unisexual ﬂ ower on long peduncles.

Teratological

staminate

M M Found in sex-reversing male tree, with some

degree of carpel initiation and development.

A number of hair-like processes – vestigial

carpels – at base.

Reduced

elongata

MF M Modiﬁ ed normal elongata ﬂ ower differs from

staminate ﬂ owers in having a thicker and

stiffer corolla tube, abortion of pistils, and

reduced ovary size and number of carpels.

Frequent warm periods and late summer; last

1–2 weeks up to 6 months, depending upon

cultivar and temperature.

Elongata

(normal type)

MF MF Elongata refers to the shape of the pistil,

terminating in ﬁ ne stigmata; lobes develop

into pyriform or cylindrical fruit, ﬁ ve laterally

fused carpels. Petals fused two-thirds of

length.

Carpelloid

elongata

MF F Transformation of the inner series of stamens

into carpel life structure. Numerous types,

different number of stamens, becoming

carpelloid and degree of carpellody from

slight to developing locules with functional

stigma. Fruit to varying degrees misshapen.

Pentandria MF F Normal hermaphrodite-type, modiﬁ ed,

unisexual, pistillate ﬂ ower through stepwise

stamen transformation to carpels, with loss

of the original carpels. Short corolla tube,

only ﬁ ve stamens of the outer whorl on

long ﬁ laments, globose and furrowed pistil.

Carpels from ﬁ ve to ten.

Carpelloid

pentandria

MF F The stamens of the outer whorl become

carpelloid. Carpellodic forms in carious

stage, especially under cool conditions.

All ﬁ ve stamens fully carpelloid and fuse

laterally, with abortion of original carpels;

ﬂ owers resemble pistillate ﬂ owers – pseudo-

pistillate.

Pistillate F F Unisexual ﬂ owers larger than MF ﬂ ower, lack

stamens. Form stable and unchanged by

environment.

M – male; F – female.

Papaya 301

The ﬂ oral primordia of ‘Solo’ is laid down 50–70 days prior to anthesis,

at a rate of about one new ﬂ ower in each leaf every 2–3 days along with

new leaves. Ovaries di erentiation begins 42–50 days prior to anthesis and

is completed within 28 days before anthesis. Stamen di erentiation begins

50–56 days before anthesis and is completed by 35 days prior to anthesis.

Female ﬂ ower bud emergence to anthesis ranges from ~46 days in Hawaii to

80 days in India, with the wide discrepancy being due to temperature.

Pollination and fruit set

In hermaphrodite populations, wind pollination is minimal as the stamens

are packed inside the corolla tube and seldom protrude prominently out of

the ﬂ ower (Fig. 11.3b). The hermaphrodite ﬂ owers are cleistogamous, i.e. the

anthers dehisce and release the pollen prior to anthesis of the ﬂ ower, leading

to self-pollination. Varieties such as ‘Sunrise’, ‘Kapoho’ and ‘Eksotika’ are

enforced self-pollinators, and seeds gathered from hermaphrodite fruit will

usually breed true to type. Self-incompatibility in cultivars is relatively rare,

though there are isolated cases when controlled self-pollinations are made.

Self-pollination in papaya also does not appear to result in any loss of vigour.

In mixed planting of pistillate and hermaphroditic trees or in purely

hermaphroditic stands, no pollination problems are experienced. Problem

occurs when dioecious cultivars are planted with an inadequate number

of male trees. In Australia, the recommended ratio of female to male is

Fig. 11.6. Stamen carpellody induced by environmental conditions (temperature,

water stress, fertilization) on young hermaphrodite trees signiﬁ cantly alters fruit

shape. The mild forms are sometimes referred to as ‘cat face’.

302 Chapter 11

8:1. However, one male tree per 15–20 female trees provides adequate

wind pollination if male trees are located with respect to prevailing winds.

Parthenocarpy in papaya is rare. Seedless fruit or fruit with very low seeds can

be produced on female trees. These fruits are generally smaller in size. Auxins

have also been reported to induce parthenocarpic fruit.

Fruit set is no problem under open pollination in an orchard. On

hermaphrodite trees, it is most common for the terminal ﬂ ower to set while the

laterals abscise. Under favourable conditions one or two laterals may be set and

only persist for 2–3 weeks or remain to produce undersized fruit that crowd

the fruit column. This crowding leads to fruit compaction and misshaped

fruit. Fruit thinning may be practised. The degree of compaction is due to the

peduncle length. Fruit set is variable; if lateral ﬂ owers are not desired and only

one fruit per leaf axil is desired, set is usually 100%; if three ﬂ owers are formed

and only one fruit is desired then the set is 33%. Annual fruit set depends upon

the length of the female sterility period in hot weather, and with one fruit per

peduncle the range is 85–95%.

Fruit

The papaya fruit is a ﬂ eshy berry, from 50 g to well over 10 kg, and superﬁ cially

resembles a melon, being spherical, pyriform, oval or elongated in shape

(Fig. 11.3). Fruit shape is a sex-linked character and ranges from spherical

to ovoid in female ﬂ owers to long, cylindrical or pyriform (pear-shaped) in

hermaphrodite ﬂ owers. The skin of the fruit is thin and usually green when

immature, turning to yellow or orange when ripe. The fruit is normally

composed of ﬁ ve carpels united to form a central ovarian cavity, which is lined

with the placenta, carrying numerous black seeds. Placentation is parietal,

with the seeds attached by 0.5–1 mm stalks. The seeds are dark grey to black

when mature and enclosed in a sacrotesta. The ovarian cavity is larger in

female fruit than hermaphrodite. The shape of the cavity at the transverse cut

ranges from star-shape with 5–7 furrows, to smooth and circular in shape.

In fruit development, all tissues in gynecia less than 1 mm are meristem-

atic. Later the outer layer of the epidermis increases in size while the

subepidermal layer continues to divide both anticlinally and periclinally. The

central parenchyma of the pericarp increases in size and divides, with the

placenta forming opposite the marginal vascular bundles. This meristematic

lasts 28–42 days and determines ﬁ nal fruit size (Fig. 11.7). Fruit growth shows

two major phases. The ﬁ rst lasts about 80 days post-anthesis, with a large

increase in dry weight occurring just before fruit maturity. Fruit development

takes 150–164 days, which is extended another 14–21 days in Hawaii in the

colder months. In subtropical areas, such as South Africa, development can

vary from 190 to 270 days (Fig. 11.2). The growth of the ﬂ eshy mesocarp

parallels seed development and total fruit growth (Fig. 11.7).

Papaya 303

Flesh colour is white in immature fruit to a pale orange-yellow, salmon

pink or red, depending upon cultivar, when ripe. Total fruit starch declines

from 0.4% to less than 0.1% during the ﬁ rst 80 days of fruit development

(Fig. 11.8). Sugars, however, do not begin to accumulate until 110 days from

anthesis, during the last 28–42 days of fruit development. Flesh total soluble

solids can be as low as 5% up to 19%.

Green fruit contains an abundance of milky latex that contains the

protease papain. The pericarp consists of a network of lacticifers that develop

close to the vascular bundles and anastomose profusely throughout the fruit.

This latex is under pressure and spurts out when the skin is pricked. Laticifers

collapse as the fruit ripens and there is little or no latex at the fully ripe stage.

Commercially, the skin is scariﬁ ed to induce latex ﬂ ow, which is allowed to dry

then collected to be later processed into papain.

CULTIVAR DEVELOPMENT

Cytogenetics and genetics

The species in the genus Carica possess nine pairs of chromosomes and a small

genome (375 Mb). Meiosis is normal in the three sex types and there are no

Fig. 11.7. The increase in papaya fruit total fresh weight and for skin, seeds and ﬂ esh

(after Qiu et al., 1995).

304 Chapter 11

known polyploid cultivars. Seeds of self-pollinated ‘Solo’ and ‘Eksotika’ and

the cross-pollinated varieties ‘Sekaki’ and ‘Khaek Dum’ can be reproduced

readily with good genetic purity, if care is taken in seed production. For the F

hybrids, such as ‘Rainbow’ and ‘Eksotika II’, seed is di cult to produce as two

inbred parents have to be crossed for production of the hybrid seeds.

Some Vasconcella species have resistance to diseases to which C. papaya

L. is susceptible, e.g. Vasconcella cauliﬂ ora’s resistance to distortion ringspot

virus. This resistance has lead to attempts to cross these species. Successful

interspeciﬁ c hybrids have been reported between other Vasconcella species but

not with C. papaya L. However, hybrids of C. papaya L. with V. cauliﬂ ora and

with V. pubescens, V. quercifolia and Vasconcella stipulata were obtained using

embryo rescue techniques to overcome post-zygotic barriers to hybridization.

In vitro propagation coupled to rapid disease resistance screening, anther

culture to generate haploid papaya lines and Agrobacterium-mediated gene

transfer has been used to develop disease-resistant papaya lines.

Sex of papaya is determined by monogenic inheritance involving three

alleles (Hofmeyr, 1938). The alleles are M for male, M

for hermaphrodite and

m for female. All homozygous dominants, i.e. MM, MM

and M

, are lethal

to the zygotes. Therefore male genotypes (Mm) and hermaphrodite (M

m) are

Fig. 11.8. Changes in fruit starch and total sugar of developing ‘Solo’ papaya fruit.

Note the dramatic increase in sugars during the last phase of fruit development

(Chan et al., 1979; Chittiraichelvan and Shanmugavelu, 1979).

Papaya 305

enforced heterozygotes, while the female genotype (mm) is a double recessive.

Seeds derived from these cross-combinations will have twice the number of

hermaphrodites compared with females (Storey, 1938, 1941a). It is possible to

self and cross male trees when there is reversal of sex from a staminate ﬂ ower

to a form that has a functional ovary, and these are used to develop inbred lines

of dioecious papayas. Sex is determined at ﬂ owering time, usually 4–6 months

after planting. Molecular probes can be used to predict the sex of papaya at

seedling stage.

Fruit size shows wide variation, ranging from about 5 cm in diameter

and 50 g in weight to over 50 cm in length and 10 kg or more in weight.

Fruit weight is a quantitative character determined by multiple alleles (Chan,

2001). Fruit shape in papaya is a sex-linked character. The female ﬂ ower

has a globose ovary, which develops into round or ovoid fruits. In contrast,

the elongata or hermaphrodite ﬂ ower has a slender, tapering ovary and this

subsequently develops into a fruit that is elongated and cylindrical or pyriform

in shape, depending on the variety of papaya.

Precocity or earliness to fruiting is a factor of the number of nodes

produced to ﬁ rst ﬂ owering node, while the number of nodes to ﬂ owering

and the internode length determine height to ﬁ rst fruit. These characters are

governed by additive gene e ects, with the hybrid having the arithmetric mean

between the two parents (Nakasone and Storey, 1955). Subhadrabandhu and

Nontaswatsri (1997) reported that height of ﬁ rst ﬂ ower and number of nodes

to fruiting were controlled by both additive and non-additive genes.

Carpellody of the stamen is the development of misshapen or ‘cat-faced’

fruits due to fusion of the stamens to the ovary tissues in hermaphrodite

ﬂ owers (Fig. 11.6). Carpellody and female sterility may involve a number of

gene pairs involving three loci, two for carpellody (c/c, c/c) and one for sterility

(s/s). Their normal alleles (+) are partially or completely dominant. The s/+

combination is normal. In c/+, the + is partially dominant over ‘c’, so there

will be some carpellody. The ‘s’ factor, whether homozygous or not (s/-), is

epistatic over the ‘c’ allele when the carpellody factors are heterozygous. The

phenotype would be normal but unstable, depending upon environmental

conditions. If either of the ‘c’ factors is homozygous (c/c), the combined

strength of the two alleles at one locus can overcome epistasis, thus exhibiting

carpellody. High heritability (h

= 82%) is obtained for carpellody, but e ective

phenotypic selection may be interfered with by the ‘change-in-rate’ type

of interaction between genotype and plant age (Chan, 1984). Increased

expression of carpellody may also be brought about by cool temperature, high

soil moisture and high nitrogen (Awada, 1961).

Flavour and odour can range from pleasantly aromatic, as in the ‘Solo’

and ‘Eksotika’ varieties, to musky, as in the ‘Maradol’ variety. Muskiness is

due to the homozygous recessive allele of a single gene (Storey, 1969). Total

soluble solids content is usually associated with sweetness and may range from

5% to about 19% total soluble solids (

Brix) in the ‘Solo’ varieties. This trait is

306 Chapter 11

governed by quantitative genes with additive e ects, and hybrids are expected

to have intermediate values between the parents.

Papaya ﬂ esh colour ranges from intense gold to deep red, with varying

intermediate shades (Table 11.2). In Malaysia and many South-east Asian

countries, the preference is the red-ﬂ eshed varieties, while Hawaii and

Australia prefer the yellow-ﬂ eshed types. Flesh colour is governed by a single

gene, with yellow (R) being dominant over red (r). Varying intermediate

shades of pink may be attributed to modiﬁ er gene e ects. All red-ﬂ eshed (rr)

varieties, such as ‘Sunrise Solo’ and ‘Eksotika’, will breed true for ﬂ esh colour,

but progenies of heterozygous (Rr) yellow F

hybrids, such as ‘Rainbow’, will

segregate in this trait.

The skin colour of papaya fruit is usually green when immature, changing

to yellow or reddish-orange when fully ripe. The ‘Morib’ is an interesting local

selection that has attractive yellow fruit skin even at an immature stage. The

tree is dwarfed and has yellowish-green foliage. Fruit skin colour is governed

by a single gene, with green (G) being dominant and yellow is expressed in a

double recessive (gg). It is di cult to identify the appropriate harvest index of

this fruit.

The old dioecious cultivars, such as ‘Hortus Gold’ (South Africa),

‘Sunnybank’ (Australia), ‘Betty’ and ‘Cariﬂ ora’ (Florida) are cross-pollinated,

yellow-ﬂ eshed and typically round fruit. ‘Cariﬂ ora’ fruits are smaller and

tolerant to the ringspot virus disease. There are also gynodioecious varieties

that are cross-pollinated, such as ‘Sekaki’, ‘Khaek Dum’, ‘Maradol’ and

‘Cibinong’. ‘Sekaki’, also known as ‘Hong Kong’, is the second most popularly

cultivated cultivar in Malaysia after ‘Eksotika’. ‘Khaek Dum’ is Thailand’s best-

known variety and is a vigorous plant that bears red-ﬂ eshed fruit weighing

about 1.2 kg with 10.6% total soluble solids content. ‘Maradol’ originates

from Cuba, is a short-stature variety that bears fruit very close to the ground.

The fruit weighs from 1 to 2 kg, attractive with ﬁ rm red ﬂ esh and 10–11%

Table 11.2. Preference of fruit characteristics in some countries.

Country Fruit size (g) Shape Flesh colour Race

Australia 800–1000 Cylindrical,

spherical

Yellow Dioecious

Cook Islands 500–1134 Pyriform Yellow Hermaphrodite

Fiji 397–510 Pyriform Red, yellow Hermaphrodite

Hawaii 397–510 Pyriform, oval Yellow, red Hermaphrodite

Mexico 1360–5443 Spherical,

elongate

Yellow, red Dioecious,

hermaphrodite

South Africa 1000–1500 Oval Yellow Dioecious

Caribbean

Islands

500–4000 Round, oval,

pyriform,

elongate

Red, yellow Dioecious,

hermaphrodite

Papaya 307

total soluble solids content. It has a characteristic musky ﬂ avour and the fruit

is quite susceptible to anthracnose. ‘Cibinong’ is an Indonesian variety with

large red-ﬂ eshed fruit (2–3 kg) and grown mainly for its high papain yield.

Commercial F

hybrids of papaya are rare, although there have been

reports of heterosis and improved yields in cross-combinations between

di erent cultivars of papaya. Agnew (1968) described a vigorous F

hybrid

derived from ‘Bettina 100A’ and ‘Petersen 170’ that was, at one time,

important in Queensland. An important hybrid developed in Taiwan that has

resistance to papaya ringspot virus disease is ‘Tainung No. 5’. This was derived

from a cross between ‘Florida’ (FL-77-5) and the ‘Costa Rica Red’. In Malaysia,

an F

hybrid called ‘Eksotika II’ was developed from the hybridization of ‘Line

19’ with its sib, ‘Eksotika’ (formerly ‘Line 20’) (Chan, 1993). The new hybrid

has similar features to ‘Eksotika’, but the yield is 14–33% higher due to the

larger fruit, weighing between 600 and 800 g. The appearance of the fruit is

more attractive, with smooth skin and high tolerance to freckles. The ﬂ esh is

ﬁ rmer and the fruit stores longer, making ‘Eksotika II’ more preferred than its

predecessor for export.

The world’s ﬁ rst transgenic papaya was ‘SunUp’, which was transformed

with coat-protein-mediated resistance to papaya ringspot virus disease.

‘Rainbow’ is the ﬁ rst transgenic commercial variety, developed from a cross

between ‘SunUp’ and the conventional cultivar ‘Kapoho’. Transgenic varieties

of ‘Kapoho’ and ‘Kamiya’ have also been developed by introduction of the

coat-protein transgene from ‘Rainbow’ through conventional hybridization

and backcrossing.

Breeding

Some papaya breeding objectives are common to all regions, with objectives

speciﬁ c to di erent localities due to climatic di erences, consumer preferences,

desired sex types and export markets (Table 11.3). These objectives have

changed little in the last 100 years. Desirable tree characteristics are tree

vigour, low and precocious fruiting, minimum expression of stamen carpellody

and female sterility if hermaphrodites are preferred, resistance to diseases

and insect pests, and yielding ability. Universally desired fruit characteristics

are smooth skin, free from blemishes, ﬁ rm fruit with thick ﬂ esh, round seed

cavity, absence of internal lumps and long shelf-life. The desired fruit size,

shape and ﬂ esh colour may di er in di erent regions (Table 11.2). An extreme

example would be a preference for papaya with the heavy musky aroma in

South-east Asia, which would not be suitable in western markets. Preference

for the small (450–650 g) ‘Solo’ fruit is increasing in tropical countries, where

export is considered. Requirements for processing cultivars are the same,

though larger fruit may be more desirable, with size and shape being uniform

if mechanization is to be considered. Flesh colour preference is usually based

308 Chapter 11

upon traditional experience and familiarity with cultivars. Total tree height

is not a good criterion to assess tree vigour, while stem diameter or girth is a

more reliable measure (Fig. 11.5). Stamen carpellody and female sterility do

not occur in dioecious cultivars.

In breeding for hermaphrodite types, selections should be evaluated

during the cool period for occurrence of stamen carpellody and again during

the warm period for female sterility. Trees that show no carpellody in winter

may show a high degree of female sterility in summer, or the opposite. Within

a speciﬁ c locality, if temperature ﬂ uctuations are not too wide, continual

selection and inbreeding can produce lines with minimum carpellody and

female sterility (Chan, 1984). In subtropical climates, where the range of

temperatures between summer and winter is large, dioecious cultivars are

more suitable.

Increased yields may be accomplished by increasing yields per tree, by

increasing density per unit area, or both (Hamilton, 1954). Usually only the

terminal ﬂ ower sets fruit and others abscise or produce small, unmarketable fruit

when they set. However, lines have been observed to produce two, three or even

four normal-sized fruit on each peduncle. Multiple fruiting is strongly inﬂ uenced

by soil fertility. Peduncles must be long enough to prevent overcrowding, which

can produce misshapen, ‘pancake-like’, ﬂ at fruit. Another method to increase

production is by increasing trees per unit area. Petioles of papaya trees are

approximately 75–100 cm, or even longer, and are more or less horizontal. This

requires at least 2 m between plants in a row. A mutant ‘Solo’ line with very poor

yields and short petioles (45–60 cm) that are positioned obliquely upright is

available, and trees can be planted at 0.9–1.2 m apart in the row. Short, upright

Table 11.3. Ideals in papaya breeding have not changed much since the following

were proposed. Additional factors have related to disease resistance (Higgins and

Holt, 1914).

Character

Tree Vigour

Early and low fruiting – wide variation exists

Freedom from branching habits

Fruit Productive but not compact fruiting

Small size for table use

Large size for animal feed and papain production

Uniformity in shape, symmetry and smoothness

Uniformity in ripening

Colouring before softening

Colour of ﬂ esh – yellow, pink or red

Easily separable without scraping ﬂ esh

Flavour – not easily described but easily recognizable

Keeping quality

Other Papain yield

Papaya 309

petiole hybrids have been produced but the yield of the commercial cultivars has

not been achieved.

A common papaya disease is the root, stem and fruit rot caused by

Phytophthora palmivora Butl., which is especially severe during wet seasons.

Early studies in Hawaii involved repeated selection for seedling mortality and

vigour, and replanting each advance generation in the same ﬁ eld resulted in a

few highly tolerant lines (Mosqueda-Vazquez et al., 1981). Cultivars showing

high tolerance to the Phytophthora root rot have also exhibited tolerance

to stem canker and fruit rot caused by the same organism. Other fruit

diseases that appear to be important enough to warrant breeding e orts are

anthracnose and chocolate spot, both caused by strains of C. gloeosporioides,

and stem-end rot caused by Phoma caricae-papayae.

The aphid-transmitted papaya ringspot virus (PRV) (papaya mosaic

virus or distortion ringspot virus) of di erent strains often limits commercial

production in most papaya-growing areas. Tolerant lines have been created,

and a dioecious cultivar named ‘Cariﬂ ora’ with strong tolerance to PRV

has been released (Conover et al., 1986). Using this material, several highly

tolerant hermaphroditic ‘Solo’ selections have been made in Hawaii. More

rapid tolerance is achieved using molecular biology and the transformation of

papaya with the virus coat protein that confers resistance (Fitch et al., 1992).

Two resistant ‘Solo’ lines, one with yellow ﬂ esh (‘Rainbow’) and the other with

red ﬂ esh (‘SunUp’), have been released in Hawaii.

The hermaphroditic papaya is naturally self-pollinating, and continuous

inbreeding has not shown inbreeding depression. Also, F

hybrids between

‘Solo’ lines have not shown hybrid vigour, probably due to a close genetic

relationship, with many genes in common, or to the fact that the vigour is

only expressed under poor growing conditions. This narrowness in germplasm

has been conﬁ rmed for ten Hawaii cultivars and three non-Hawaii cultivars

by DNA analysis at 80% similarity. Heterosis has been observed in F

s of

crosses between ‘Solo’ and widely di erent papaya accessions and between

interspeciﬁ c crosses involving V. cauliﬂ ora × V. monoica and V. goudotiana × V.

monoica (Mekako and Nakasone, 1975; Manshardt and Wensla , 1989a,b).

Cultivars

Wide variability is shown by the papayas grown in various countries; with

few exceptions, most cannot be classiﬁ ed as horticultural ‘cultivars’ (Table

11.4). Plantings are usually heterogeneous and seeds are obtained from open-

pollinated fruit. A number of horticultural cultivars have been reported to

produce relatively uniform progenies (Table 11.5). Stabilizing characteristics

in dioecious cultivars is more di cult than in hermaphroditic ones, as the

genotype of the male with respect to the fruit characteristics is unknown. In

hermaphroditic cultivars, proper selection and self-pollination can stabilize

310 Chapter 11

characteristics at a more rapid rate. The Hawaiian ‘Solo’ type is perhaps one

of the few cultivars that has been continuously inbred since its introduction to

Hawaii in 1911 from Barbados (Yee, 1970). Solo cultivars such as ‘Kapoho’,

‘Sunrise’, ‘Sunset’ and ‘Waimanalo’ have been inbred for many generations.

Table 11.4. Papaya ‘cultivars’ reported in the literature; many are variable and not

true cultivars.

Country Cultivar Sex type Flesh colour

Australia Improved Petersen Dioecious Yellow

Guinea Gold Hermaphrodite Yellow

Sunnybank/S7 Dioecious Yellow

Richter/Arline Dioecious Yellow

Americas

Mexico Verde

Gialla

Cera

Chincona

USA – Florida Cariﬂ ora Dioecious Yellow

Betty Dioecious Yellow

Homestead Dioecious Yellow

USA – Hawaii Kapoho Solo Hermaphrodite Yellow

Sunrise Hermaphrodite Red

Waimanalo Hermaphrodite Yellow

Rainbow Hermaphrodite Yellow

Venezuela Paraguanera

Roja Red

Caribbean

Barbados Wakeﬁ eld

Graeme 5, and 7

Cuba Maradol Hermaphrodite Red

Trinidad Santa Cruz Giant

Cedro

Dominican Republic Cartagena Hermaphrodite Yellow

Asia Yellow

India Coorg Honey Dew Hermaphrodite

Coimbitor 2 Dioecious Yellow

Indonesia Semangka Hermaphrodite Red

Dampit Hermaphrodite Red

Malaysia Eksotika Hermaphrodite Red

Sekaki Hermaphrodite Red

Philippines Sinta Hermaphrodite Red

Taiwan Tainung No. 5 Hermaphrodite Red

Thailand Sai-nampueng Hermaphrodite Red

Khaek Dam Hermaphrodite Red

South Africa Hortus Gold Dioecious Yellow

Kaapmuiden – Yellow

Honey Gold Dioecious Yellow

Papaya 311

CULTURAL PRACTICES

Propagation

Papaya is almost entirely propagated from seeds in commercial cultivation.

Sound seeds usually germinate after 2 weeks in the polybags and are ready

to transplant at the 8–12-leaf stage, after about 6 weeks. The seeding rate for

papaya is very low as dry papaya seeds are light, weighing about 14.5 g per

1000 seeds. To establish a hectare of papaya, about 100 g of seed is required.

Approximately 100–150 g of seeds with 80% germination are needed to

produce the 2000 plants needed for one hectare.

Papaya seed can be harvested when the fruits reach ‘colour break’ stage.

Growers select trees with desirable characteristics, from which seeds, generally

from open-pollinated fruit, are saved. This seed produces uniform progenies

if from a single cultivar. The seeds are non-recalcitrant and can be dried to

moisture levels of 9–12% for long-term storage. Seeds harvested fresh from

fruit have very low and variable germination. Removal of the sarcotesta and

soaking in gibberellic acid promotes germination; uniformity of germination

is further enhanced by seed drying and cool-temperature storage at 15°C

for 30–50 days. Papaya seeds without the sarcotesta that are well-dried and

stored at 5°C retain 60–70% germination for 5 years (Chan and Tan, 1990).

Seeds may be sown in trays ﬁ lled with a suitable medium, peat pots,

polyethylene bags or directly in the ﬁ eld. Germination occurs in 12–20 days.

Seedlings are transplanted into 7.6 cm peat pots or into 10 cm plastic bags

Table 11.5. Fruit and tree characteristics of ﬁ ve Hawaiian cultivars. Data are

averages from tests conducted at three locations (winter harvest only).

Characteristics Cultivar

Kapoho Higgins Line 8 Waimanalo Sunrise

Height to ﬁ rst ﬂ ower

(cm)

147 97 169 76 91

Fruit weight (g) 343 367 516 695 425

Soluble solids (%) 15.7 15.9 15.0 15.2 14.5

Flesh colour Yellow Yellow Yellow Yellow Red

Carpellodic fruit (%) 0 1.0 1.0 0.8 –

Other culls (%) 16 12 5 10 –

Marketable (kg/tree) 17 31 26 39 –

Phytophthora

resistance

ISRRI

Virus resistance

IT HT S S S

R = resistant; I = intermediate; S = susceptible.

HT = high tolerance; IT = intermediate tolerance; S = susceptible.

312 Chapter 11

at the two-leaf (cotyledonary leaves) stage. Seedlings grown in containers

should be hardened gradually in sunlight and ﬁ eld-transplanted around 1.5–2

months after germination, at about 20 cm high. In ﬁ eld planting up to 15–20

seeds are sown in each hole. Upon germination seedlings are thinned out to

leave ﬁ ve or six seedlings to grow to ﬂ owering. So many seeds are planted in

each hole to allow for birds and ﬁ eld mice loss. At ﬁ rst ﬂ owering, a vigorous

plant of the desired sex is kept and the others removed.

Allan (1964) was the ﬁ rst to report the success of propagating papaya by

cuttings. Large, leafy, lateral shoots that developed after winter were initially

used as cuttings for rooting under intermittent mist. In subtropical countries,

the cool winter checks growth and temporarily overcomes apical dominance,

resulting in the proliferation of lateral shoots. Availability of cuttings became

less season-dependent when they were induced from vigorous 1–2-year-

old trees by topping o the shoot terminus to remove the apical dominance.

The methods for induction and proliferation of suitable-sized lateral shoots

for cuttings were improved further with the application of cytokinin and

gibberellic acid mixtures. Vegetatively propagated papaya ﬂ ower 1–3 months

earlier and are 30 cm lower bearing.

Scion shoots from cultivars ‘Co-1’ and ‘Honey Dew’ can be successfully

cleft-grafted on to uniformly established seedlings (Airi et al., 1986). Patch and

T-budding can also be used, but the success rate is poorer than cleft grafting.

Field grafting can be used to replace female trees. The union is established

in about 2–3 weeks and the female tree is cut back to about 60 cm from the

ground.

The early success of in vitro propagation of papaya was limited because

the sex of the seedling plants used could not be ascertained. Later, Litz and

Conover (1978) reported successful regeneration of papaya plantlets by

culturing apices of mature, ﬁ eld-grown papaya plants in modiﬁ ed Murashige

and Skoog media. A ﬁ eld trial of in vitro plantlets indicated that they

propagated true to sex without somaclonal reversion (Drew, 1988). Besides

greater uniformity, the other beneﬁ ts were earlier bearing, lower bearing

height and improved yield.

Field preparation

Field preparation in many areas is poorly done due to lack of appropriate

equipment or rough terrain. Subsoiling or ripping down to 50 cm or more

is desirable on heavy or compacted soils so roots can penetrate deeply (see

Fig. 3.2). Subsoiling provides better drainage if done parallel to the contour

lines. Discing, levelling and furrowing follow standard practice. Planting holes

30–45 cm in diameter are best dug with a soil auger attached to tractors.

Raised beds are used if there is a chance of ﬂ ooding (see Fig. 3.3).

Papaya 313

Transplanting and plant spacing

After about 6–8 weeks in the nursery, the seedlings should reach the eighth

to twelfth-leaf stage and are most suitable for ﬁ eld planting. In rainfed areas,

ﬁ eld planting is done at the beginning of the rainy season. Seedlings grown

in pots and bags are planted directly, with the removal of the pot or bags.

Transplanted plants must be watered soon after planting to settle the soil

around the root system.

Spacing between plants and between rows varies widely. Universally

practised is the single-row system, with between plant spacing ranging from

1.8 to 3 m and between row spacing varying from 1.8 m to as much as 3.6 m

(see Fig. 3.7b). The between-row spacing largely depends upon degree of

mechanization; a standard tractor requires ca 3 m. The most frequently used

spacing is 2.0–2.5 m within row × 2.5 m, giving a density of 1600–2000

plants/ha. The double-row system, with 2 m between a set of rows and 3.5 m

between double rows, is used. Normally, two or three seedlings are planted

in each hole, spaced about 30 cm apart. When the plants start ﬂ owering,

the female plants are removed, leaving only one hermaphrodite plant per

point. Polyethylene mulch over the beds prevents moisture losses and greatly

minimizes weed growth within the beds (Fig. 3.7b). Organic mulches of

grasses, wood shavings, rice hulls or other kinds of material are also beneﬁ cial.

Irrigation

Non-irrigated ﬁ elds in Hawaii are located in a region with 2500–3125 mm

of rain, fairly well-distributed throughout the year. However, occasional

droughts of 2 or 3 months occur. Low soil moisture tends to shift the sex type

to male and results in lower fruit yields, while high moisture levels can lead to

excessive production of misshaped carpellodic fruit, with rapid tree growth.

Dioecious cultivars fare better unless moisture stress is severe. A monthly

minimum rainfall of 100 mm is needed without supplementary irrigation

for some production. Irrigation should replace at least the moisture lost by

pan evaporation, and 1.25 pan evaporation is required for maximum yield of

mature trees (Fig. 11.9). Young trees only need about 0.3–0.5 pan evaporation.

Good production occurs with 60–90 l/tree/week immediately after planting or

during the wet season and 120–240 l/tree/week during the dry period.

Irrigation may be by ﬂ ooding between the row space by furrows running

along both sides of the rows of trees or via microsprinklers or jets or drip.

Irrigation intervals of around 10–15 days may be necessary to sustain

production, unless this interval is broken by rainfall. Papayas are wind-

pollinated, and overhead sprinkling reduces pollen dissemination and

therefore is not recommended. A drip system must be capable of providing

the maximum amount rather than average demand. If a tree requires

314 Chapter 11

56 l water/day but 114 l maximum during the dry season, the delivery system

must have the capacity to deliver the maximum requirement. One emitter per

tree has been su cient for the ﬁ rst 3–4 months, but thereafter two emitters,

one on each side of the tree, have been found necessary. A single micro-

sprinkler (30 l/h) can also meet requirements.

Pruning

Normal tree pruning is not practised. Side shoots produced by some cultivars

during the juvenile stages or enforced when the plant apex is damaged are

removed as early as possible to maintain a single-stemmed tree. If the apex

is damaged or destroyed, one shoot nearest the terminal is maintained to re-

establish the tree. Some lower leaves are removed to facilitate harvesting,

improve penetration of spray materials and generally to increase marketable

yields (Ito, 1976). No statistical di erences are found in total soluble solids,

fruit size, number of fruits and marketable yield after a year of leaf pruning

when only 15 fully expanded leaves are retained. One fully expanded

mature leaf can provide photosynthetates for about 1500 g of fruit on the

column on ‘Solo’ varieties. Trees that have very large fruits (4–5 kg each)

Fig. 11.9. Relation between yield of marketable fruit and the water application as a

fraction of pan evaporation (Awada et al., 1979).

Papaya 315

may have fewer than ten fruits developing at a time on the fruit column, with

new ﬂ owers abscising.

Fertilization

Papaya is a fast and continuously growing tree that provides fruits all the

year round. An abundant supply of nutrients at regular intervals is needed

to sustain good growth and production. In general, an adequate supply of

nitrogen and phosphorus should be provided during the early stages to ensure

optimum foliage, trunk and root development. However, at the fruiting stage,

the level of potassium should be raised, while the level of phosphorus should

be reduced, as high levels reduce fruit size. The level of nitrogen remains

somewhat unchanged through the juvenile and fruiting stages because foliage

is continuously produced. Tentative ranges of critical levels for bearing plants

of ‘Kapoho’ Solo are: N = 1.10–1.40%, P = 0.15–0.18% and K = 2.5–3.5%

(Awada and Long, 1980).

Papaya is sensitive to boron deﬁ ciency, especially when cultivated

on sandy soil. Plants su ering from this deﬁ ciency exhibit characteristic

symptoms: slight yellowing and downward curling of the leaf tips, with very

slight necrosis of the leaf tips and margins. The leaves are brittle in texture

and claw-like. During fruiting, secretion of milky latex often occurs on the

fruit surface, which subsequently turns brown in colour. At the later stage, the

fruit surface becomes rough or ‘bumpy’, giving the fruit an overall distorted

or malformed appearance. Treatment of boron deﬁ ciency is by soil or foliar

application of borate.

Diversity of soil types, climatic conditions and practices make it necessary

to develop recommendations for speciﬁ c areas based upon soil analysis and

preferably foliar analysis. In the sandy loam soils of North Moreton, Australia,

a pre-plant application of 0.5 kg of 5:7:4 complete fertilizer, 0.25 kg of single

superphosphate and 1.0 kg of lime per individual plant (over 1 m

area) is

recommended. For post-plant application, 100 g/plant of 10:2:16 complete

fertilizer is given at about 2-month intervals, with monthly application of

150–200 g per plant site during summer and autumn. In the second year,

250 g per plant is given at 2–3-month intervals. Because of boron deﬁ ciency

problems in this area, 20 g of borax is applied at 3–4-month intervals and

30g/plant is given the second year at about 7–8-month intervals.

Pest management

Diseases

The importance of frequently reported papaya diseases (Table 11.6) varies,

and they may be widespread or localized. Phytophthora commonly causes

316 Chapter 11

collar and root-rot and sometimes stem canker and fruit rot in papaya. Papaya

is predisposed to the disease in areas with a high water table, poor aeration

and persistent high rainfall. Phytophthora with Pythium also cause seedling

‘damping-o ’, a serious disease during the nursery stage. Phytophthora root

rot is a major concern in all areas where the same land is used repeatedly

for production. Depending upon soil type and rainfall, the replant problem

may become very serious within two or three successive plantings, with

seedling mortality up to 45% (Nakasone and Aragaki, 1973). Alternatively,

virgin soil (soil never planted to papaya) is placed into each planting hole in

a replant ﬁ eld; this allows the seedling to become established before the roots

penetrate beyond the virgin soil and they are then less a ected by root rot

fungus. Development of cultivars with strong tolerance through breeding

is slow, with the cv. ‘Waimanalo’ being such a product. Seedling damping o

immediately after germination is caused by a complex of organisms. The use

of sterilized germination medium with good aeration and control of moisture

are preventative measures.

Fruit diseases generally occur postharvest. Incidence of some fruit diseases

can be minimized by ﬁ eld sanitation and ﬁ eld application of appropriate

fungicides, while others can be reduced by careful handling of fruit, as these

organisms infect through wounds. Anthracnose, a preharvest infection fruit

surface rot, and stem-end rot, a harvest wound rot, are the two most common

postharvest rots of papaya. At the early stage of the infection, anthracnose,

C. gloeosporioides, is manifested as tiny dark spots on the skin of fruit, and if

left untreated, they form larger, depressed lesions when the fruits start to ripen.

In more severe cases, especially when the fruits turn full colour, the lesions

may coalesce with each other and the pinkish spores of the fungi are evident

in the depressed lesions. The infected fruit becomes soft, dark coloured and

unattractive.

Bunchy or malformed top is a relatively new disease of papaya. The

disease is a complex involving both thrips and a normally saprophytic fungus

Cladosporium oxysporum. Severely infected plants remain stunted and are

slow to recover. Symptoms are typiﬁ ed by the appearance of new ﬂ ushes

of leaves that are malformed, with leaf spots and ‘shot-holes’ (ranging from

1 to 3 mm wide). Short, light-yellow streaks (due to feeding by thrips) are

usually interspersed with the spots. The ‘Eksotika’ and ‘Solo’ varieties are very

susceptible at the juvenile stage.

The papaya virus disease, papaya ringspot virus (PRSV) has become the

limiting factor for commercial production in many areas. This disease has

been referred to as papaya mosaic virus (PMV) and distortion ringspot virus

(DRV). The fact that PRSV is suspected to be a number of a di erent viruses

is due to the variations in the expressed symptoms associated with di erent

races. Papaya ringspot virus (PRSV) has severely restricted papaya production

in Thailand, the Philippines and Taiwan and has also been recorded as the

major papaya disease in India, Hawaii, the Caribbean, Malaysia and Vietnam

Papaya 317

Table 11.6. Some important diseases and disorders of papaya.

Common name Organism Parts affected Distribution

Phytophthora blight

Phytophthora palmivora

Root, stem, fruit Widespread

Pythium root rot

Pythium aphnidermatum

Root Widespread

Damping off

Pythium aphanidermatum,

P. ultimum, Phytophthora

palmivora, Rhizoctonia sp.

Seedling stem at soil line Widespread

Collar rot

Calonectria crotalariae

Base of trunk, crown roots Hawaii, Thailand

Powdery mildew

Oidium caricae

Underside of leaves, petioles Widespread

Alternaria fruit rot

Alternaria alternata

Fruit body Widespread

Blackspot

Cercospora papayae

Fruit body Widespread

Anthracnose,

chocolate spot

Colletotrichum gloeosporioides

Ripe fruit body Widespread

Soft rot

Rhizopus stoloifer

Injured mature fruit at stem end Widespread

Stem-end rot

Fusarium solani

Wounded mature fruit at stem end Widespread

Phoma rot

Phoma caricae-papayae

Stem end, wounded area Widespread

Phomopsis rot

Phomopsis sp.

Stem end, wounded area Widespread

Stemphylium rot

Stephylium lycopersici

Stem end, wounded area Widespread

Fruit rots

Botryodiplodia sp.

Stem end, wounded area Widespread

Cladosporum sp.

Fruit body

Stem-end rot

Mycosphaerella sp.

Stem end

Continued

318 Chapter 11

Common name Organism Parts affected Distribution

Yellow crinkle Tomato big bud organism Leaves, ﬂ owers Australia

Papaya ringspot

virus

Aphids: Myzus persicae, Aphis

gossypii

Leaves, stems and petioles, fruit ring-spots or

distorted

Widespread

Bunchy top

(mycoplasma-like

bodies)

Empoasca papayae (leafhopper)

Death of growing point Caribbean, tropical

America

Die back Unknown Yellowing and death of crown leaves Australia, Israel

Yellow crinkle Leaf hopper Yellowing of old leaves; crown leaves show

translucent areas

Australia

Table 11.6. Continued.

Papaya 319

(Table 11.6). In Taiwan, papaya is restricted to annual rather than perennial

production and cultivation and is often carried out in large net-houses to keep

out the disease-carrying, non-persistent aphid vectors.

The symptom on the fruit is dark green, concentric rings, hence the name

for the disease. On the younger stem and on the petioles, elongated, green,

water-soaked streaks appear. Infected plants also show chlorosis in the young

leaves, and the upper portion of the crown appears prominently yellowed.

Fruits are also low in sugar content with poor ﬂ avour.

There are no control methods once the plant is infected. Eradication,

sanitation methods and isolating the papaya-growing area by a papaya-free

bu er zone allow papaya to continue to be grown. An orchard or growing

area isolated far enough from disease sources remains uninfected because by

the time aphids can move from the virus source to the healthy orchard, they

are non-infective due to the non-persistent characteristic of the virus in the

aphid. Also, curcurbit plants should not be interplanted in papaya orchards as

they are alternate hosts to the virus. A cross-protection method using a mild

strain confers some immunization, enabling plants to be 82% more productive

than unprotected trees in ﬁ eld trials. Breeding and selection has resulted

in development of tolerant varieties such as ‘Cariﬂ ora’, ‘Tainung No. 5’,

‘Sinta’ and ‘Eksotika’-derived breeding lines. The genetically modiﬁ ed variety

‘Rainbow’ transformed with the virus coat protein gene has shown excellent

resistance to the disease in Hawaii. Transforming of papaya with the viral

coat protein has been successful; however, each virus race has a speciﬁ c coat

protein, so di erent coat protein genes are needed in di erent areas.

INSECTS AND MITES

Many insects have been reported on papaya, but most are unimportant and

the damage is negligible or easily controlled. A few may cause severe problems

in localized areas (Table 11.7). Aphids, such as Aphis gossypii and Myzus

persicae, are important only as vectors of PRSV. Fruit ﬂ ies are troublesome in

the export trade as papayas may need to receive a disinfestation treatment for

fruit ﬂ y eggs and larvae before export. Rarely are fruit at the mature-green to

colour-turning stage infected; egg lay becomes a problem when fruits have

25% or more skin colour (Seo et al., 1982).

Several species of mites are known to infest papaya (Table 11.7), the

commonest being the red spider mite (Tetranychus cinnabarinus) and the broad

mite (Hemitarsonemus latus). The mite population increases dramatically

during the dry and cool spells, and they can be located on the undersurface

of emerging leaves and petioles. In severe infestations, the leaves are shed

prematurely and the shoot terminals su er die back. They also cause extensive

scarring (netted corky appearance) on the surface of the fruits when they feed

on the epidermal tissues.

Thrips (Thrips parvispinus) are common on papaya ﬂ owers during the

blooming season. However, during the early stages of plant growth, they feed

320 Chapter 11

on the supple young leaves and shoot and provide the infection site for the

invasion by the saprophytic fungus C. oxysporum.

There are three species of scale insects known to infest papaya in Malaysia

but only two, i.e. the palm scale, Aspidiotus orientalis, and the oriental scale,

Aonidiella orientalis, are economically important. A. orientalis is considered the

most destructive. Both the nymph and adult feed on the leaf, stem and fruit.

A. orientalis is only found on the fruit and seldom on other parts of the plant.

Table 11.7. Some important insects and pests of papaya.

Common name Scientiﬁ c name Parts affected Distribution

Melon ﬂ y

Dacus cucurbitae

Fruit Widespread

Oriental fruit ﬂ y

Dacus dorsalis

Fruit South-east Asia,

Philippines, Western

Paciﬁ c, Hawaii

Dacus melanotus

Fruit Cook Islands, South

Paciﬁ c

Mediterranean fruit

ﬂ y

Ceratitis capitata

Fruit Hawaii, Mexico,

Central, South

America, Middle

East, Africa

Fruit ﬂ y

Toxotrypana

curvicauda

Fruit American tropics,

Florida

American fruit ﬂ y

Anastrepha

fraterculus

Fruit Subtropical, tropical

America

Caribbean fruit ﬂ y

Anastrepha

suspensa

Fruit Florida, Caribbean

Green peach aphid

Myzus persicae

Virus vector Widespread

Red and black ﬂ at

mite

Brevipalus

phoenicis

Fruit Widespread

Broad mite

Hemitarsonemus

latus

Emerging leaves,

leaves of young

seedlings

Widespread

Carmine mite

Tetranychus

cinnabarinus

Lower surface of

mature leaves

Widespread

Texas citrus mite

Eutetranychus

banksi

Mature leaves Widespread

Eutetranychus

orientalis

Mature leaves Thailand

Citrus red mite

Panonychus citri

Mature leaves Widespread

Monkeys Kenya, Barbados

Birds Four species Caribbean, Hawaii

Bats Vanuatu, South Paciﬁ c

Papaya 321

Nematodes

This pest, common only on sandy soils, damages the root systems and causes

stunting of the plants. Two nematodes, the root-knot nematode (Meloidogyne

incognita) and reniform nematode (Rotylenchulus reniformis), are the major

problems.

Weed management

Hand weeding, especially around young seedlings, mowing and mulching

are often used for weed control. Plastic mulch is very e ective against annual

broadleaved weeds but ine ective against perennial grasses or sedges. Post-

emergence herbicides such as glyphosate are currently widely used. Glyphosate

is e ective for a wide spectrum of weed species, and as a systemic herbicide its

e ects are not visible for a number of days. A common practice in some areas

is to interplant papaya orchards with tree crops that later become the principal

crop. Herbicides selected for the principal crop must also be compatible with

papaya and registered for use for both crops.

Orchard protection

Papayas develop extensive root systems but are vulnerable to strong winds,

especially when accompanied by rain. Windbreaks of appropriate shrubs or

small trees planted close together across prevailing wind directions can protect

the trees from severe damage. Selection of windbreak plants is best left to those

with local experience of the region.

HARVESTING AND POSTHARVEST HANDLING

Harvesting

Harvesting is easy when fruits can be reached by hand; as trees become

taller some form of harvesting aid, such as poles and ladders, must be used.

In Hawaii, most growers use a rubber cup or chisel-shaped metal tool with a

‘V’ attached to a long pole, which is placed against the bottom of the fruit or

against the peduncle and pushed upwards, snapping the fruit at the peduncle.

The falling fruit is caught by the picker with the other hand or removed from

the cup. The harvested fruits are accumulated in a bucket, tray or cloth

picking bag. These methods are possible only with the small ‘Solo’ fruit. When

the container is full, it is emptied into padded or lined bins left on ﬁ eld roads.

An experienced harvester can harvest from 360 to 450 kg per 8-h day. Various

hydraulically operated mechanical harvesting aids, such as mobile platforms,

322 Chapter 11

are sometimes used. The harvesters stand on the platform, which is adjusted

to be at fruit height, as an operator slowly drives it down the rows.

The degree of ripeness for harvesting depends upon distance to markets.

Fruits may be one-quarter to one-half ripe for local markets. Fruits to be

transported long distances or exported are harvested at colour break to one-

quarter ripe, depending upon the cultivar’s ripening characteristics and

season. Colour assessment is based upon the judgement of pickers. The Hawaii

grade standard requires fruits to have 11.5% total soluble solids with the

colour-break stage normally meeting this standard. Green immature fruit do

not ripen well and have a total soluble solids value that is frequently less than

10%, giving a bland taste.

Postharvest treatment

The need for postharvest treatments depends upon the importing countries.

Overseas markets require disinfestation treatments to eradicate fruit ﬂ y larvae

and eggs from the fruit before shipment. The vapour heat method was the

ﬁ rst disinfestation treatment used in the 1950s, and after the banning of the

fumigant ethylene dibromide in 1984, vapour heat and forced heat treatment

again became the industry standard. The fruit core temperature in these

heat treatments reaches at least 47.2°C and the total treatment time is about

7 h (Paull and Chen, 1990). The alternative method is irradiation at a dose

of about 250 Gy. This low irradiation dose sterilized the fruit ﬂ y larvae and

eggs, preventing them from completing their life cycle. Irradiation at 250 Gy

does not provide postharvest disease control and needs to be coupled with a

postharvest disease control programme.

A fungicide–wax combination is recommended prior to packing (Paull and

Chen, 1990). Incidence of storage diseases can be reduced by ﬁ eld spraying

and proper care in harvesting and handling to avoid wounding and bruising.

Skin injury is a major problem and is caused mostly by impact and abrasion

during harvesting (Quintana and Paull, 1993). The latter is mainly caused

when harvested fruits are being dropped into ﬁ eld bins with rough side walls

and bottom. Careful handling is essential to avoid these unsightly blemishes,

which provide an invasion site for postharvest rots.

Following the disinfestation treatment, papayas are packed into cartons in

a screened area to prevent re-infestation by fruit ﬂ ies. Defective fruits are culled

before and/or after disinfestation and fruits are graded for size and colour

and hand-packed into cardboard cartons with a capacity of about 4.5–10

kg. Cartons from areas requiring insect disinfestation are fully sealed to meet

regulatory requirements, while fruits from other areas can be in open-topped

cartons. Count size ranges from 6 to 18, depending upon fruit and carton size.

Fruits are marketed as colour break, one-quarter ripe, half-ripe and three-

quarter ripe and are normally ready to eat when there is three-quarters or

Papaya 323

more colour on the skin. Foam mesh sleeves, foam padding on the bottom

of the carton or paper wrapping prevent abrasion injury, which is a major

problem in fruits still having green areas of skin.

Room cooling and forced air cooling are most commonly used to pre-cool.

Hydro-cooling is possible; however, rapid cooling after insect disinfestation

treatments can lead to skin scalding. Storage recommendations are in the

range of from 7 to 13°C and from 90 to 95% RH. At 7–10°C, storage life is

limited by chilling injury, while at 10–13°C ripening slowly occurs (Chen and

Paull, 1986). Papaya fruit at colour-turning (break) stage can be stored at 7°C

for 14 days and will ripen normally when transferred to room temperature

(Fig. 5.3). Chilling injury symptoms include skin scald, hard lumps in the

pulp around the vascular bundles and water-soaking of ﬂ esh. Fruits become

progressively less susceptible to chilling stress as they ripen, and the symptoms

occur after 14 days at 5°C for mature green fruit and 21 days for 60%

yellow fruit. Skin scald can be induced in colour-break fruit after chilling at

1°C for 24 h.

Shelf-life extension of 1–1.5 days was obtained when papaya were

stored at 12°C in 1–1.5% oxygen for 6 days. Low oxygen (1.0–5%), with or

without high CO

(2–10%), reduces decay and delays ripening. High CO

(30%) adversely a ected internal colour, aroma and ﬂ avour, while there is

no residual e ect of 10% CO

on decay control, though skin degreening is

delayed. At 10°C, fruit could be stored for 36 days in 8% CO

, 3% O

and still

have 5 days at 25°C for retail. Ethylene removal prior to storage has shown

variable results. Controlled atmosphere has not shown dramatic improvement

in storage life and the economic cost of the treatment needs to be balanced

against the improvement in fruit storage life and quality.

The optimum temperature for fruit ripening is between 22.5 and 27.5°C,

with fruit taking 10–16 days to reach full skin yellowing from the colour-break

stage (An and Paull, 1990). Severe weight loss and external abnormalities

become signiﬁ cant at temperatures higher than 27.5°C. Fully ripe fruit at the

edible stage can be held at 1–3°C. Loss of ca. 8% of initial weight from colour-

break papaya produces ‘rubbery’, low-gloss, unsaleable fruit.

Marketing

Most papayas produced in the tropics are consumed locally, due to long

distances to markets and the di culty in handling the large fruit size.

Marketing standards for trade are normally set by agreement between the

shipper and the wholesale or retail buyer. In Hawaii, standards for Hawaiian-

grown papaya have been developed. Fruit must conform to the ‘Solo’ type,

with similar cultivar characteristics as to size and shape, must be mature

with a deﬁ nite tinge of yellow at the blossom end, must be clean, well-formed

and meet the total soluble solids standards, averaging not less than 11.5%

324 Chapter 11

for any lot of papayas, provided not more than 5% by count of fruit in the

lot have soluble solids less than 10.5%. Fruit is sized into the following size

classiﬁ cations: small 284–369 g; medium 369–454 g; large 454–907 g; and

extra large over 907 g. A major problem with the standard is the di culty in

achieving same size and skin colour that will ripen together in the carton.

Other typical requirements include that the fruit must be free from decay,

breakdown, internal lumps and other undesirable characteristics and free

from various categories of injury, including insect and mechanical injury.

WORLD PRODUCTION AND UTILIZATION

Production

Thirty-eight countries are reported to produce papaya. Six countries produce

a minimum of 100,000 MT/year. Brazil is the largest producer, followed by

Mexico, Indonesia, India, Zaire, Taiwan and the Philippines (Anonymous,

2003). World production is in excess of reported ﬁ gures, as considerable

production occurs in small island countries in the tropics; backyard and

subsistence-farm production and that consumed locally may not enter into

the world production statistics.

Utilization

The fruit is the major product from this species, though young leaves and

male ﬂ owers are used as vegetables and in soap. Nutritionally, the papaya is a

good source (Table 11.8) of calcium (30 mg/100 g), and an excellent source

of provitamin A and ascorbic acid (Wenkam, 1990). Papayas are consumed

fresh as breakfast fruit, dessert or in salads. In Asia, green fruits are cooked

as a vegetable or made into preserves. Papayas are also processed into various

forms, such as dehydrated slices, chunks and slices for tropical fruit salads and

cocktails, or processed into puree for juices and nectar base, usually frozen,

and as canned nectar, mixed drinks and jams. Papaya puree is the basis for

remanufacturing of many products. Papaya puree is processed aseptically

or frozen, with yield of ca. 50%. The ﬂ avour of aseptically processed puree is

stable during processing and after 6 months in ambient storage, with some

colour changes noted.

Papain is a proteolytic enzyme that digests proteins and is used as a

meat tenderizer, as a digestive medicine in the pharmaceutical industry, in

beer brewing, tanning industries and in the manufacture of chewing gum.

Papain production is primarily centred in Tanzania and India, where labour is

abundant and inexpensive. The latex is obtained from green papaya by making

about four surface lancings on the fruit and catching the drippings in cups,

Papaya 325

with yields of 88.5–227 g/tree of dried latex per year. Approximately 2.27 kg

of fresh latex will produce 0.45 kg of dried latex.

In processing papayas 22% of the waste is seed. The seed oil content

of 33% on a dry weight basis is considered high when compared to seeds of

other fruit. Protein content of 29% on a dry weight basis is comparable to that

of soybean, with 35%. Papaya seed meal, with 40% crude protein and 50%

crude ﬁ bre, appears to be a potentially rich animal feed. A salad dressing is

also made from ground papaya seeds.

FURTHER READING

Alvarez, A.M. and Nishijima, W.T. (1987) Postharvest disease of papaya. Plant Disease

71, 681–686.

Gonsalves, D., Vegas, A., Prasartsee, V., Drew, R., Suzuki, J.Y. and Tripathi, S. (2006)

Developing papaya to control papaya ringspot virus by transgenic resistance,

intergeneric hybridization, and tolerance breeding. Plant Breeding Reviews 26,

35–78.

Table 11.8. Nutritive value of hermaphrodite ‘Solo’-type papaya (Wenkam, 1990).

Amount per 100 g

edible portion

Proximate

Water (g) 87

Energy (kJ) 192

Protein (g) 0.39

Lipid (g) 0.06

Carbohydrate (g) 12.2

Fibre (g) 0.58

Ash (g) 0.57

Minerals

Calcium (mg) 30

Iron (mg) 0.2

Magnesium (mg) 21

Phosphorus (mg) 12

Potassium (mg) 183

Sodium (mg) 4

Vitamins

Ascorbic acid (mg) 84

Thiamine (mg) 0.03

Riboﬂ avin (mg) 0.04

Niacin (mg) 0.33

Vitamin A (IU) 1093

326 Chapter 11

Kim, M.S., Moore, P.H., Zee, F., Fitch, M.M.M., Steiger, D.L., Manshardt, R.M., Paull, R.E.,

Drew, R.A., Sekioka, T. and Ming, R. (2002) Genetic diversity of Carica papaya L. as

revealed by AFLP markers. Genome 45, 503–512.

Marler, T.E. (1994) Papaya. In. Scha er, B. and Andersen, P.C. (eds) Handbook of

Environmental Physiology of Fruit Crops Vol. 2. Subtropical and Tropical Crops. CRC

Press, Boca Raton, Florida, pp. 216–224.

Nakasone, H.Y. (1986) Papaya. In. Morselise, S.P. (ed.) CRC Handbook of Fruit Set and

Development. CRC Press, Boca Raton, Florida, pp. 277–301.

Paull, R.E., Nishijima, W., Reyes, M. and Cavaletto, C. (1997) A review of postharvest

handling and losses during marketing of papaya (Carica papaya L). Postharvest

Biology and Technology 11, 165–179.

Zhou, L., Christopher, D.A. and Paull. R.E. (2000) Defoliation and fruit removal e ects

on papaya fruit production, sugar accumulation, and sucrose metabolism. Journal

of the American Society for Horticultural Science 125, 644–652.

(R.E. Paull and O. Duarte)

PINEAPPLE

Pineapple (Ananas comosus (L) Merr.) is also called piña (Spanish), abacaxi

(Portuguese), annachi pazham (Tamil) or nanas (Malaysian), with many

languages using the South American Tupian language name ananas. This

is the only species in the bromeliad family grown commercially for its fruit.

The fruit was called ‘piña’ by 15th-century Spanish explorers because of its

resemblance to a pine cone. The fruit develops by fusion of ﬂ oral parts (Fig.

12.1). Pineapple is eaten fresh and canned, and the juice is sold singly and in

combination with other fruit juices. Cut pieces are used as a dessert, in salads

and cooked meat dishes, and in fruit cocktail mixes. Today, the pineapple is

found in almost all the tropical and subtropical areas of the world, and it ranks

third in production of tropical fruits, behind bananas and citrus.

BOTANY

Introduction

Pineapple is in the bromeliad family, which has about 45 genera and 2000

species. The Bromeliaceae originated in tropical America except for one species,

Pitcairnia felicana (Aug. Chev.) Harms & Mildbr., a native of tropical West Africa

(Collins, 1960). Plants are herbaceous or shrubby and classiﬁ ed as epiphytic

or terrestrial. Pineapple (A. comosus (L.) Merr.) is by far the most economically

important bromeliad. Other species of Ananas and Bromelia yield edible fruits:

Ananas bracteata (Swartz) Grisebach, Ananas kuntzeana Mez., Ananas longifolia

(Rudge) L.B. Smith & M.A. Spencer, Ananas nudicaulis (L.) Grisebach, Bromelia

antiacantha Bertoloni, Bromelia balansae Mel., Bromelia chrysantha Jacquin,

Bromelia karatas L., Bromelia hemisphaerica Lamarck, Bromelia nidus-puellae

(André) André ex Mez., Bromelia pinguin L., Bromelia plumieri (E. Morren) L.B.

Smith, and Bromelia trianae Mez. The more common are consumed locally,

under names such as cardo or banana-do-mato (bush banana), piñuelas

(small pineapple), or karatas, gravatá and caroata (derived from Amerindian

328 Chapter 12

names given to terrestrial bromeliads). For example, B. balansae Mel. is called

gravata in Brazil and it has 80–120 fruit per plant, each weighing 6–14 g;

the skin is brown and the ﬂ esh is white when ripe. Many other bromeliads

are cultivated as ornamentals, gathered for ﬁ bre extraction or used in

traditional medicine.

Open

Flowers

Floral

Bract

Fig. 12.1. Pineapple inﬂ orescence and ﬂ ower, and fruit. The small purplish ﬂ owers

open from the base of the inﬂ orescence. The fruit is composed of fused fruitlets and

the skin of sepals partially covered by a bract.

Pineapple 329

Origin and distribution

The pineapple was ﬁ rst seen by Europeans when Columbus and his men

landed on the island of Guadaloupe during the second voyage in 1493. Early

exploration by botanists in South America indicated the area of origin to be

south-eastern Brazil, Paraguay and northern Argentina, because of the

abundance of wild species. Based on materials collected in South America,

Leal and Antoni (1980) proposed an area further north, between 10° N and

S latitudes and 55–75° W longitude. This general area includes north-western

and eastern Brazil, all of Colombia and Guyana, and most of Venezuela.

At the time of Columbus’s arrival, the pineapple was already widely

distributed throughout most of tropical America. The antiquity of this fruit

even at that time is evidenced by the presence of distinct types, all of which

were nearly or completely seedless. Its wide uses as food, wine and medicine

at the time of Columbus’s arrival in the Americas and the absence of

recognizable wild progenitors of the cultivated pineapple are further evidence

of pineapple’s antiquity (Collins, 1948). Distribution of pineapple from the

Americas is attributed to Spanish and Portuguese explorers and was aided by

the resistance of crowns and slips to dessication. Pineapple was introduced

into Africa at an early date and reached southern India by l550. Before the

end of the l6th century, it had become established in China, Java and the

Philippines (Collins, 1949).

At least 79 countries in the tropics and subtropics produce measurable

quantities of pineapple (http://www.fao.org, 2008). Yields (kg/ha) are highly

variable and, for those countries producing more than 5000 MT, range

from 8 t/ha in Nigeria to 47 t/ha in Australia. This great variation in yields

results from a number of factors. Small farms in countries that use the best

technology tend to have higher yields than do large plantations utilizing the

same technology, because in-ﬁ eld losses are easier to control on the small farm.

Yields, on average, are much lower in developing countries, where access to

inputs is limited by lack of capital. The exception occurs when a multinational

corporation establishes a plantation in a developing country where labour

costs are low. Cultivar di erences also contribute to variations in yields. Where

the predominant cultivars are ‘Smooth Cayenne’ and the Pineapple Research

Institute of Hawaii hybrid clones 73-50 and 73-114 (also known as MD-2,

‘Gold Extra Sweet’, MG-3 and ‘Mayan Gold’), yields are higher, probably more

than twice as high even with the best technology, than are the spiny-leaved

‘Queen’ and ‘Spanish’ cultivars (Table 12.1). Prevailing climate also has a

moderating e ect on yields, with yields at the same level of technology being,

on average, lower in the warm tropics than at higher latitudes.

330 Chapter 12

ECOLOGY

Major areas of commercial cultivation are found between 30° N and

S latitudes, with some areas considered marginal for various reasons

(Bartholomew and Malézieux, 1994). Minor plantings extend pineapple

Table 12.1. Characteristics of pineapple groups and clones (after Leal and Soule,

1977).

Characteristic

Group

Spanish Queen Abacaxi Cayenne Maipure

Leaves Spiny Spiny Spiny Smooth Smooth

Fruit

Weight (kg) 0.9–1.8 0.5–1.1 1.4 2.3 0.8–2.5

Shape Globose Conical Conical Cylindrical Cylindrical

Colour skin Large, deep

eyes

O, R

Deep eyes

Y Flat eyes

Y to OR

Colour ﬂ esh Pale Y to W Deep Y Pale Y to W Pale Y to Y W to deep Y

Core Large Small Small Medium Small–

medium

Taste Spicy acid,

ﬁ brous

Sweeter, less

acid, low

ﬁ bre

Sweet,

tender,

juicy

Sweet,

mildly acid,

low ﬁ bre,

juicy

Sweeter than

‘C’, ﬁ brous,

tender,

very juicy

Market

Canning FFFVGF

Fresh

Local GGGG G

Export VG G F to P F F to P

Disease

problems

Gummosis,

wilt

resistance

resistant

than

‘Cayenne’

Resistant Mealy bug

wilt

Unknown

Clones Red Spanish Queen Abacaxi Smooth

Cayenne

Maipure

Singapore

Spanish

MacGregor Abakka Cayenne

Lisse

Perolera

Green

Selangor

Natal Sugar loaf Smooth

Guate-

malan

Lebrija

Castilla Ripley Papelon Typhone Monte Lirio

PRI-67 Alexandria Venezolana St. Michael Abacaxi

Cabezona Amarella Esmeralda Rondon

Abbreviations: C, cayenne; F, fair; G, good; O, orange; OR, orange-red; P, poor; R, red; VG, very

good; W, white; Y, yellow.

Pineapple 331

production to subtropical areas with mild climates beyond 30° N and S

latitudes and even under protective shelters. Pineapple cultivars show

considerable variation in their plant growth and fruit size when grown in

di erent environments (Chan and Lee, 1985). Greater variation in cultivar

yield response occurs in less favourable environment.

Soil

Pineapple can be grown in a wide variety of soil types, with good drainage

and aeration being crucial. It is grown in the peat soils of Malaysia, sandy and

sandy-loam soils of Ivory Coast, Queensland, Australia and Oaxaca, Mexico,

and in the highly weathered red volcanic soils of Hawaii. The ideal soil type for

pineapple is a sandy or well-aggregated clay soil with good drainage to prevent

waterlogging and root diseases (Hepton, 2003).

In Hawaii, pineapple is grown primarily on silt loams, silty clay loams and

silty clays, primarily oxisols and ultisols. These soils are well suited to pineapple

because they occur in areas having high insolation, have good water-holding

capacity but are well aggregated, so drainage is adequate to very good. Most

of these soils are red in colour, are derived from basaltic rocks and volcanic

ash alluvium, and are high in oxides of iron, aluminium and, in some cases,

manganese. Soils with high levels of manganese can result in manganese-

induced iron chlorosis because soil pH is maintained around 4.5, which results

in high levels of soluble manganese in the soil solution. Generally, a pH range

of 4.5–5 is considered best for pineapple (Hepton, 2003), primarily to reduce

the incidence of heart and root rot caused by Phytophthora spp.

Climate

Rainfall

The pineapple is an obligate Crassulacean acid metabolism (CAM) plant with a

xerophytic characteristic that enables it to withstand long periods of drought.

The leaves have a water-storage parenchyma that serves as a reservoir of

moisture during drought. The leaves are covered with trichomes and a highly

cutinized upper epidermis. The stomata are small and are located in furrows

on the underside of the leaf. At the early inﬂ orescence development stage, 38%

of water use occurs at night when the stomata are open. At midday, no water

loss is detected. Water-use e ciency is 3.3 times greater for pineapple than for

wheat (Bartholomew and Malézieux, 1994). Pineapples are produced under

a wide range of rainfall, from 600 mm to more than 3500 mm annually,

with the optimum for good commercial cultivation being from 1000 to 1500

mm. In Hawaii, pineapple is grown in areas where the rainfall ranges from

510 to 2540 mm, with an average of 1190 mm annually. Pan evaporation

332 Chapter 12

in the major growing area of Wahiawa, Hawaii is 1850 mm per year (5 mm

per day). Even if annual rainfall closely approximates the optimal range, poor

distribution can result in periods of serious drought. In Loma Bonita and

Acayucan (Mexico) 89% and 82% of the rainfall, respectively, occurs between

June and November.

Despite the xerophytic characteristics of pineapple, growth is adversely

a ected by prolonged dry periods. Plants may not attain the desirable size

by the scheduled time for chemical ﬂ ower induction. However, most areas of

the world where pineapple is cultivated have fairly high humidity, which can

reduce the impact of drought. At higher elevations, night air is cooled enough

to produce heavy dew, which condenses on the leaves and drains into the

heart of the plant and into the soil, providing supplemental moisture that can

be absorbed by roots in the leaf axils.

Temperature

In the absence of drought, temperature is the most important factor in

pineapple cultivation. The prevailing temperature determines the rate of plant

and fruit growth and, in conjunction with solar radiation, has a dramatic

inﬂ uence on fruit total soluble solids and acidity, which are the primary

determinants of fruit quality. Under controlled conditions, the rate of root

growth at 18°C was less than 15% of the maximum, while the optimum

temperature was 29°C (Fig. 12.2). Leaf growth responds to temperature

in a manner similar to that of the roots, but growth is closer to 20% of the

maximum at 18°C and the optimum temperature is 32°C (Sanford, 1962).

Photosynthesis and plant growth approach a maximum when the day

temperature is near 30°C and there is about a 10°C diurnal range between

day and night temperatures (Malézieux et al., 2003).

Warm days and cool nights provide the optimum environment for net

assimilation and growth. Growth is slow at an average temperature of 20°C

and at night temperatures below 15°C. In the cool season or in the cooler,

higher elevations, growth is delayed; leaves are upright, rigid and shorter;

the number of slips is higher; fruit may be smaller with prominent eyes; the

ﬂ esh is opaque, higher in acidity and sugars are lower (Bartholomew et al.,

2003). However, the e ects of seasonally cool temperature are confounded

with insolation, because irradiance decreases with the temperature during the

winter months.

Pineapple does not tolerate frost, and even night temperatures of 7–l0°C

for a few h for several weeks during winter can result in leaf-tip necrosis. Such

low temperatures can also cause fruit injury. A range of desirable minimum

night temperatures would be 15–20

C, while a comparable day temperature

range would be 25–32°C. The interaction of solar radiation and temperature

signiﬁ cantly a ects the days from forcing to harvest. Further away from the

equator the amplitude of the temperature di erence between seasons increases

and number of days from planting to harvest also increases.

Pineapple 333

Where topographic variation exists, changes in elevation provide a

means of achieving a desirable range of temperature conditions (Fig. 12.3).

Near the equator, the highest yields and fruit of the best quality are generally

obtained at higher elevations. In Kenya, an equatorial country, pineapple

is grown at more than 1400 m, while on Mindinao, the Philippines (8° N),

most pineapple is grown at an elevation of 250 m or higher. While elevation

provides an opportunity to provide an ideal environment for pineapple in

the tropics, economics, particularly labour costs, often determines where the

crop is grown. Thailand (~15° N) is the world’s largest producer of pineapple,

yet most of the crop is grown near sea level in this warm tropical country.

South Africa and southern Queensland, Australia represent the extremes of

the climatic range over which pineapple is grown, and winter temperatures

severely restrict growth rates. In southern Queensland, fruit initiated by forced

ﬂ owering during the 3 coldest months all mature within about 1 month, as

growth resumes as spring temperatures increase (Fig. 12.3). In South Africa

and southern Queensland, minimum temperatures occasionally approach

or reach freezing point for short durations, while in most other areas where

pineapple is grown winter temperatures rarely fall below 10°C.

Cool night temperatures coincident with shortened day length stimulate

ﬂ oral induction if the plant is of su cient size. Cool temperatures also increase

Fig. 12.2. Effect of temperature on leaf and root growth (redrawn from Sanford,

1962).

334 Chapter 12

the responsiveness to ﬂ ower-inducing compounds (Bartholomew et al., 2003)

and shorten the time to ﬂ oral induction under a short-day regime. High

temperatures (>28°C) make chemical ﬂ ower induction more di cult, with the

percentage of plants forced decreasing linearly with increasing temperature.

In Mexico between June and August, and in Thailand in most months of the

year, fruit produced for processing generally have low acidity and total soluble

solids (TSS). In Mexico, this lower quality is due to the combined e ect of high

temperature, excessive rain and an increased number of cloudy days, while in

Thailand the response is due primarily to overly warm temperatures.

The ‘Smooth Cayenne’ group is the more productive in tropical conditions,

while the ‘Queen’ group is grown mainly in subtropical areas. ‘Smooth

Cayenne’ is most sensitive to low-temperature-induced internal browning

(chilling injury, blackheart), while ‘Red Spanish’ is less sensitive.

Sunlight

Most pineapple is grown in regions with high insolation, at least in part

because the crop is well adapted to areas with low rainfall. While the light level

required to saturate photosynthesis of a pineapple leaf is believed to be less

than 25% of full sunlight, high irradiance is required to sustain the high levels

of productivity found in commercial plantations, where plant population

Fig. 12.3. Effect of latitude as an indicator of solar radiation and temperature on the

time from forcing to harvest, 26° S is for Nambour, Australia, 18° S is Madagascar

and 5° N is Ivory Coast.

Pineapple 335

densities can reach or exceed 75,000 plants/ha. In Hawaii, the maximum day-

length range between the shortest and longest days is about 2.5 h, but solar

irradiance in December is about 50% of that occurring during midsummer.

Sun injury of leaves is relatively uncommon in most regions where pineapple

is grown, as air temperatures do not exceed about 35°C. When greater than

35°C, the leaf ’s surface temperature on a horizontally displayed leaf is likely

to exceed 50°C. Because of close plant spacing on commercial plantations,

pineapple leaves are erect, as they are supported in an upright position by the

leaves of closely spaced adjacent plants. Erect leaves help to distribute high

midday irradiance uniformly over the leaf surface and help to reduce the heat

load borne by the leaf. Due to relatively erect leaf orientation, about 95% of

light interception occurs in a pineapple canopy at a leaf area index (LAI) of

about 5.0.

Fruit weight is signiﬁ cantly correlated with mean irradiance from planting

to harvest (Fig. 12.4). The lower fruit weight associated with lower irradiance

is due to a lower plant weight at forcing. Fruit acidity in the month before

harvest declines with solar radiation levels and there is no signiﬁ cant e ect on

total soluble solids. Cloudy days reduce pineapple growth and result in smaller

plants and smaller fruit, with higher acid and lower sugar contents. A rule of

thumb is that for each 20% decrease in solar radiation, the yield decreases

~10%. Mutual shading at higher planting densities leads to a linear decrease

in individual fruit weight and a curvilinear increase in total yields as density

increases.

Intense sunlight, particularly during fruit maturation, can cause sun-

scalding of fruit, with the ‘Queen’ group being more susceptible than ‘Smooth

Cayenne’. The damaging e ect can be prevented by shading the fruit or

spraying a reﬂ ective coating, for example lime and a spreader-sticker, as is

done in Queensland, Australia. Fruit covered with newspapers or grass, or the

gathering and tying of the longest leaves over the fruit is observed in Okinawa

and Taiwan and is also a common practice in Mexico and Brazil.

Photoperiod

The normal season for ﬂ owering of ‘Smooth Cayenne’ is during the winter,

in response to cool temperatures and shortened photoperiod. However,

the plant will ﬂ ower naturally at any time of the year, depending upon the

planting material and time of planting (Bartholomew et al., 2003). Because

of this response, Gowing (1961) classiﬁ ed ‘Smooth Cayenne’ as a quantitative

but not an obligate short-day plant. Under controlled conditions, ‘Smooth

Cayenne’ plants grown under 8-h days all ﬂ owered; 69% ﬂ owered under

10-h days, 53% under 12-h and 30% under 16-h days (Friend and Lydon,

1979). Interruption of the dark period by illumination suppresses ﬂ owering.

Before the advent of artiﬁ cial ﬂ oral initiation, plants that were not induced

to ﬂ ower during the winter months generally ﬂ owered in the late summer

and early autumn, producing winter and spring fruit. Some minimum

336 Chapter 12

plant size is necessary before natural ﬂ owering will occur, and cool night

temperatures apparently enhance the e ects of short days (Bartholomew et

al., 2003).

GENERAL CHARACTERISTICS

Stem

The stem of a mature ‘Smooth Cayenne’ plant is 30–35 cm long and club-

shaped, with the thickest diameter being 5–8 cm just below the apex.

Internodes are short, ranging from 1 to 10 mm, with the middle region of

the stem having the longer internodes. There is an axillary bud at each node

(Krauss, 1949). Adventitious roots grow through the epidermis and vary in

length from a few millimetres near the top of the stem to several centimetres

at its base. Axillary buds can produce shoots, typically called suckers in the

industry, which are the source of a second or ratoon crop. Suckers may be

retained on the mother plant or they may be harvested for use as planting

material. Such harvesting is a relatively costly operation because the shoots

must be cut from the mother-plant stem. Suckers harvested for use as

Fig. 12.4. Effect of mean irradiance from planting to harvest on average fruit weight,

and mean irradiation 2 weeks prior to harvest on fruit juice titratable acidity and

total soluble solids (TSS) of ‘Smooth Cayenne’ pineapple fruit grown in the Ivory

Coast.

Pineapple 337

planting material can range in weight from a few hundred grams to more

than a kilogram fresh weight (Fig. 12.5). Large suckers are unsuited for use

as planting material because the shock of removal tends to induce precocious

inﬂ orescence development. Shoots, commonly called slips, also are produced

from buds in the axils of the ﬂ oral bracts on the peduncle. The stem of slips is

comma-shaped, in contrast with the straight stem of suckers and crowns. If

slips are allowed to remain on the plant for a few months after fruit harvest,

they can grow to 250–450 g.

Roots

Adventitious roots are produced from preformed root primordia in the stem.

Krauss (1948) separated the roots into ‘soil’ roots, which develop at the base

of the stem and form the underground root system, and ‘axillary’ roots, which

form above the soil surface in the leaf axils. The underground root system is

relatively dense and typically extends to a depth of 15–30 cm. The roots of

pineapple plants grown in deep, loose, fertile soil free from parasitic organisms

and can grow downward more than 50 cm and extend 1.83 m beyond the

plant within a year’s time.

Fig. 12.5. Pineapple fruit showing multiple crowns, slips at the base of the fruit and

suckers at the base of the plants (from Coppens d’Eeckenbrugge and Leal, 2003).

338 Chapter 12

The axillary roots will absorb both water and nutrients, facilitating the

utilization of foliarly applied nutrients. The main absorptive area of the root is

in the unligniﬁ ed white tissue of the root tip. Roots without white tissues at the

root tips are not actively growing, are ine cient in absorbing water and may

have been lost because of root rot and nematode feeding.

Leaves

Leaves are produced in a spiral around the stem in a tight rosette (Fig. 12.1). A

dormant axillary bud is found at the midpoint of each leaf on the main stem.

By counting from a leaf or bud at a selected node on the stem upwards in a

spiral, the 13th leaf or bud will be directly above the initial leaf or bud and ﬁ ve

turns around the stem will have been made, resulting in a 5/13 phyllotaxy

(Bartholomew and Kadzimin, 1977).

The number of leaves increases regularly, with an average of ﬁ ve or

six leaves per month. Old leaves do not abscise, and a mature plant may

have 70–80 active leaves. The most frequently mentioned developmental

index for carbohydrate and nutrient status is the whorl of leaves designated

and described as the D-leaves by Sideris and Krauss (1936) and ﬁ rst used by

Nightingale (1942). Usually, the D-leaves are in the fourth whorl from the

base of the plant, and not more than three leaves would qualify as D-leaves

at any one time. These are the longest (80–100cm) and the youngest nearly

physiologically mature set of leaves. In non-fruiting plants, the leaf base of

these leaves is only slightly broader than the green blade. In ‘Smooth Cayenne’

a small group of marginal spines is found near the leaf base and near the

tip. Also, a short area of spines is formed on new growth of the leaves after

temporary cessation of leaf growth due to adverse conditions. There is always

a slight constriction at the point where leaf expansion was interrupted.

There are a number of structures in pineapple plants and other

bromeliads that contribute to their strong resistance to moisture stress.

The position and trough shape of the leaves, the presence of trichomes, and

stomata located in furrows beneath trichomes on the underside of the leaf

are features that enhance drought resistance. Long, multicellular trichomes

are found in abundance on the lower side (abaxial) of the leaf and less on the

upper (adaxial) side. It is generally believed that the trichomes absorb moisture

and nutrient solution and reduce water loss through the stomata by forming a

dense covering over the stomata.

A unique internal feature of bromeliads, including the pineapple leaf,

is a water-storage tissue that is colourless and translucent. This tissue can

be identiﬁ ed with the naked eye in the adaxial part of transverse sections of

the leaf and contrasts with the chlorophyllous mesophyll tissue beneath. The

width of both tissues in leaf cross section varies with age and environmental

factors. In the pineapple-growing district of Wahiawa, Hawaii, the water-

Pineapple 339

storage tissue of a turgid, fully developed leaf from a ﬁ eld-grown plant

occupies about half the leaf cross section at the middle of the blade. This tissue

becomes narrower as moisture stress increases. This tissue is absent towards

the tip and margins.

Carbon is assimilated in pineapple leaves by the Crassulacean acid

metabolism (CAM) pathway. The principal features of this pathway are large

diurnal ﬂ uctuations in organic acids, mainly malic, and an inverted pattern

of gas exchange due to the ﬁ xation of CO

into malate at night and its release

and reduction to carbohydrate during the day (Malezieux et al., 2003). The

inverted pattern of gas exchange is the result of changes in the intercellular

concentration. At night the CO

acceptor molecule phosphoenolpyruvic

acid (PEP) is produced using stored carbohydrate. The PEP is carboxylated

to form oxaloacetic acid, which is then reduced to form malate. The malate

is transported to the cell vacuole, where it is stored until the following day.

Shortly after sunrise, malic acid moves from the vacuole to the cytoplasm, is

decarboxylated to produce a molecule of CO

and a molecule of pyruvic acid;

the low intercellular CO

level begins to increase and the stomata soon close.

In the morning to early afternoon hours, the released CO

is ﬁ xed and reduced

to carbohydrate by normal Calvin cycle or C-3 photosynthesis. As the malic

acid level declines, the intercellular CO

level also decreases and the stomata

open. During the remainder of the afternoon hours, CO

is assimilated from

the atmosphere by conventional C-3 photosynthesis. Normal night opening of

pineapple stomata requires sunlight on the previous day.

Inﬂ orescence and ﬂ ower

The inﬂ orescence is terminal (Fig.12.1), developing from the apical meristem

of the plant. Peduncle elongation begins at the time reproductive development

is initiated and continues after ﬂ ower formation. The ﬁ rst sign of ﬂ oral

initiation, whether natural or induced, is a rapid increase in diameter of the

apical meristem, and 5–6 days after this change takes place, the peduncle

begins to elongate. It continues to elongate as the inﬂ orescence develops.

The inﬂ orescence can consist of up to 200 individual trimerous ﬂ owers with

a phyllotaxy of 21/55 for large fruits of ‘Smooth Cayenne’ and 13/34 for

smaller ratoon crop fruit (Ekern, 1968). Individual ﬂ owers are composed of

three sepals, three petals, six stamens and a tricarpellate ovary. One to several

ﬂ owers open each day over a period of 3–4 weeks, starting from the base of

the inﬂ orescence (Okimoto, 1948). The fruitlets develop from ﬂ owers that do

not abscise and each ﬂ ower is subtended by a ﬂ eshy bract (Fig. 12.1). The style,

stamens and petals wither and the remaining ﬂ oral parts develop into the

fruitlet (Okimoto, 1948). The ovules and pollen grains are functional but seeds

are not normally formed as ‘Smooth Cayenne’ is strongly self-incompatible.

340 Chapter 12

When ﬂ ower production ceases, the apical meristem again reverts to the 5/l3

phyllotaxy, with a transition area of short leafy bracts, followed by the growth

and development of the crown (Fig. 12.1).

Fruit

The fruit, more precisely deﬁ ned as a coenocarpium (a multiple fruit derived from

ovaries, ﬂ oral parts and receptacles of many coalesced ﬂ owers), also commonly

referred to as a sorosis (a syncarp of fused fruitlets from inferior ovaries), is

topped by a leafy stem referred to as the crown (Fig. 12.5). The fruit ‘shell’ is

composed mainly of sepal and bract tissues and the apices of the ovaries, while

the edible ﬂ esh is primarily composed of ovaries, the bases of sepals and bracts,

and the cortex of the axis, which is an extension of the peduncle.

Fruitlets develop from ﬂ owers that do not abscise (Fig. 12.1). The style,

stamens and petals wither, with remaining ﬂ oral parts developing into the

fruitlet (Okimoto, 1948). Yeast and bacteria can enter through the nectary

gland, and mature fruit is not sterile (Rohrbach and Apt, 1986). In the

normal fruit there are 8 gently sloping rows and 13 shorter, steeper rows of

ﬂ owers. The number of fruitlets can be estimated by counting the fruitlets on

the long, gently sloping spiral and multiplying by eight, the number of spirals

(Bartholomew and Paull, 1986). It takes approximately 4 months from the

end of the last open ﬂ ower to fruit maturity, and the total time from ﬂ oral

initiation to harvest takes between 6 and 7 months (Figs 12.6 and 12.7).

Temperature signiﬁ cantly accelerates or delays development.

Fig. 12.6. Pineapple fruit growth and development in Hawaii.

Pineapple 341

Cell division is completed prior to anthesis, with all further development

being the result of cell enlargement (Okimoto, 1948). Fruit weight increases

about 20-fold from the time of ﬂ owering until maturation (Fig. 12.6). Fruit

development studies have shown that fruit weight and its components (core,

fruitlets, the collective ﬂ esh, fruit shell) increase in a sigmoid fashion after the

inﬂ orescence is initiated (Fig. 12.6). Crown growth increases about 30–45

days after fruit growth has commenced. The crown has been reported to have

no direct e ect on the development of the fruit, though crown removal early

in fruiting leads to greater fruit weight. The most marked changes in ﬂ esh

composition occur in the 3–7 weeks prior to, and at, the half-yellow-shell

colour stage. Just prior to this stage, fruit translucence can start to develop,

and translucent development continues after harvest. Titratable acidity

declines and the total soluble solids gradually increases, being more rapid

in the last 6 weeks, as the fruit approaches the fully ripe stage. Fruit sugars

continue to increase through to senescence, unless the fruit is harvested.

Fig. 12.7. The growth cycle of a pineapple crop to harvesting the ﬁ rst ratoon crop in

relation to the various stages of development and crop age (Rohrbach, no date).

342 Chapter 12

CULTIVAR DEVELOPMENT

Cytogenetics and genetics

Information on cytogenetics and genetics comes from early studies conducted

at the former Pineapple Research Institute of Hawaii. Chromosome counts of

‘Cayenne’, ‘Queen’, ‘Spiny Samoa’, ‘Ruby’, ‘Pernambuco’, ‘Spiny Guatemala’,

an F

hybrid between ‘Cayenne’ and an unknown wild-type from Brazil and

B. pinquin L. showed the pineapple cultivars to possess n = 25 chromosomes

and B. pinquin has n = 48, with no irregularities in meiosis (Collins, 1960).

Several triploid plants with 75 chromosomes are found among the F

hybrids.

The triploids appear to be products of the conjugation between an unreduced

‘Cayenne’ egg cell with 50 chromosomes and normal haploid pollen of a

Brazilian wild type. The commercial cultivar ‘Cabezona’ is a natural triploid

with 75 chromosomes (Collins, 1933).

Collins and Kerns (1938) described about 30 heritable mutant forms in

‘Smooth Cayenne’ ﬁ elds, most being undesirable. One desirable processing

mutant form is for elongated fruit. Collar-of-slips, a condition in which

excessive numbers of slips are either attached directly to fruitlets at the base of

the fruit or massed around its base, occurs in successive vegetative generations

(Fig. 12.5). These plants are continuously rogued out. This character is

dominant and occurs in a heterozygous state in ‘Smooth Cayenne’. Spiny

leaf is due to a homozygous recessive gene, and the smooth leaf condition

of ‘Smooth Cayenne’ is carried as a heterozygous dominant. However, it is

unstable and mutates frequently to the spiny leaf type; other spiny conditions

also occur. Self-incompatibility in pineapple is an advantage in commercial

production of seedless fruit and in cross-pollination. Pollen shows good

viability for several cultivars, except that of the triploid ‘Cabezona’. A single S

locus with multiple alleles and gametophytic control of pollen phenotype are

involved in self-incompatibility (Brewbaker and Gorrez, 1967), in which the

pollen tube growth beyond the upper third of the stylar canal is inhibited.

Breeding and cultivars

Breeding

Pineapple breeding and selection objectives vary with the locality, but almost

always emphasize disease and insect resistance (Coppens d’Eechkenbrugge et

al., 1997; Chan et al., 2003). More recently, development of cultivars for fresh

fruit consumption has been a major focus. Populations have been produced

from crosses to allow selection of improved types. This selection involves

constant roguing of undesirable mutations and selection of superior types.

Mutation continues to occur within selected clones, so the e ects of selection

are not permanent, and without continued rouging and selection, commercial

Pineapple 343

ﬁ elds can revert to conditions of an unselected ﬁ eld population. In Hawaii,

advanced hybrid clones were derived from many years of breeding (Chan

et al., 2003). In Australia, sources of germplasm consist of selections from

Queensland ‘Cayenne’ clones, hybrid populations, meristem-cultured plants

from known clones and introductions from other countries. Hybrid selections

were derived from ‘Cayenne’ crosses with rough leaf types such as ‘Queen’,

‘Ripley Queen’, ‘MacGregor’, ‘Alexandra’ and ‘Collard’. ‘Singapore Spanish’, a

spineless plant with good fruit quality, has been widely used in their breeding

programme. Malaysia has similarly used ‘Smooth Cayenne’ and ‘Singapore

Spanish’ in their hybrid breeding programme. Breeding programmes in Puerto

Rico, Brazil, Taiwan, the Philippines and South Africa maintain the major

cultivars in their germplasm collections.

‘Smooth Cayenne’ is highly susceptible to mealy bug wilt (Table 12.1),

though a few clones have shown variable resistance, which is transmitted to

seedling progenies. Other cultivars and species have shown some resistance:

‘Red Spanish’, ‘Pernambuco’, ‘Queen’, Ananas ananasoides, Ananas bracteatus,

Pseudananas sagenarius and some hybrids involving ‘Cayenne’ and resistant

cultivars (Collins, 1960). In Hawaii, hybrid No. 59-656 is resistant to

P. cinnamoni and Phytophthora parastica root and heartrot diseases.

Concomitant with breeding for disease and insect resistance has been the

attempt to develop cultivars suitable for fresh fruit export. A suitable clone

should have high yield, high sugar, a good balance of sugars to acids, high

ascorbic acid and appealing ﬂ avour. These must be incorporated in a clone

having the desired disease resistance, fruit shape and weight.

Cultivars

Collins (1960) developed a botanical key to the genera and species and the

major characteristics of ﬁ ve ‘Cayenne’ clones for selection of appropriate

parents. A later taxonomic key identiﬁ ed 18 commercial clones with

vernacular names and descriptions (Antoni and Leal, 1980); this included a

new group, ‘Maipure’, composed of smooth-leaved clones (Table 12.1). Clones

in this group are primarily grown in South America. The major fruit and leaf

characteristics of the principal clones can be placed in ﬁ ve phenotypic groups

(Table 12.1). ‘Monte Lirio’ and ‘Perolera’, formerly unclassiﬁ ed, are placed

in the ‘Maipure’ group. ‘Cayenne’ and ‘Maipure’ smooth-leaved groups di er

in that leaves of the former group exhibit a few spines near the leaf tip, while

the latter group shows leaf piping (leaf margins) with a greyish streak, due

to folding over of the lower epidermis on to the upper leaf surface (Collins,

1960). Pineapple isozyme variation indicates ﬁ ve genetically diverse groups

that do not perfectly match these phenotypic groupings (Loison-Cabot, 1992;

Aradhya et al., 1994). A brief discussion of the ﬁ ve horticultural groups

follows.

Cayenne group: ‘Smooth Cayenne’ is the standard for processing and

for the fresh fruit trade because of its cylindrical shape, shallow eyes, yellow

344 Chapter 12

ﬂ esh colour, mild acid taste and high yields. In most areas, ‘Smooth Cayenne’

constitutes a mixture of clones due to new introductions from mutations, lack

of roguing and other various sources. Local selections are mostly known by

their areas of origin, such as ‘Sarawak’ in Malaysia. ‘Champaka’ is a selection

of ‘Smooth Cayenne’ originating in India and widely grown in Hawaii. The

group is susceptible to mealy bug wilt and nematodes.

Queen group: This group generally produces smaller plants and fruit with

spiny, shorter leaves than the ‘Cayenne’ group. ‘Queen’ is grown in South

Africa, Australia and India for the fresh fruit market. ‘Z-Queen’ or ‘James

Queen’ is reported to be a mutant of ‘Natal Queen’ and is a natural tetraploid.

Spanish group: The plants are generally small to medium, spiny-leaved,

vigorous and resistant to mealy bug wilt, but susceptible to gummosis caused

by the larvae of the Batrachedra moth. It is acceptable for the fresh fruit

market but not favoured for canning, due to deep eyes and poor ﬂ esh colour.

‘Red Spanish’ or ‘Espanola roja’ is the major cultivar in the Caribbean region.

‘Singapore Spanish’, or ‘Singapore Canning’ and ‘Nanas Merah’, are the

principal canning pineapple in West Malaysia because of their adaptability to

peat soil. The ﬂ esh has a bright yellow colour. Other Malaysian cultivars are

‘Masmerah’, a spineless type with large fruit, and ‘Nanas Jabor’, a Cayenne–

Spanish hybrid that is susceptible to fruit marbling and cork spot. ‘Cabezona’,

a natural triploid, is an exception, having large plants and fruit weighing

4.5–6.5 kg. It is grown primarily in the Tabasco State of Mexico and a small

area of Puerto Rico where local consumers prefer the larger fruit. The Puerto

Rico clone PR 1-67 is suspected to be a hybrid between ‘Red Spanish’ and

‘Smooth Cayenne’, as these were the only clones grown in adjacent ﬁ elds. The

fruit has light yellow ﬂ esh with adequate sugar and resistance to gummosis,

is fairly tolerant to mealy bug wilt, and has good slip production and good

shipping qualities.

Abacaxi group: This group is grown mostly in Latin America and in

the Caribbean region. Py et al. (1987) called this the Pernambuco group.

The fruit is not considered suitable for canning or for fresh fruit export, but

the juicy, sweet ﬂ avour of the fruit is favoured in the local markets. ‘Perola’,

‘Pernambuco’, ‘Eleuthera’ and ‘Abacaxi’ are the principal clones in Brazil,

along the eastern Espirito Santo in the south through Bahia and Pernambuco

to Paraibo.

Maipure group: This group is cultivated in Central and South America as

fresh fruit for the local markets. These clones may be of interest to breeders in

the western hemisphere as they constitute a gene pool of adapted forms almost

unused in breeding programmes.

The ‘Smooth Cayenne’ cultivar dominates commercial production for

canning and is also one of the major fresh fruit varieties. However, ‘Smooth

Cayenne’ has objectionably high acidity during the winter months, so newer

hybrids such as 73-114 (MD-2, MG-3), which have comparable yield and a

better sugar to acid balance during the winter months, have rapidly expanded

Pineapple 345

in importance as fresh fruit varieties and now dominate international trade.

Other varieties of some importance commercially include ‘Queen’ and

‘Spanish’, both of which are primarily consumed fresh.

CULTURAL PRACTICES

Planting material and propagation

Propagules used in commercial pineapple production include fruit tops

(crowns), shoots borne on vestigial fruits at the base of the fruit (slips) and

shoots borne at any position on the stem (suckers) (Fig. 12.5). Genetic

variation in numbers of slips produced per plant exists between clones

and cultivars. Two or three crowns can be produced as a result of high-

temperature injury during early inﬂ orescence development, but large numbers

of crowns (multiple) or fasciation of crowns is considered a genetic defect and

such plants typically are rogued. Types and sources of vegetative propagules

are kept separate, because weight, nutritional history and development

environment are believed to a ect time to establishment and optimum plant

size for fruiting, as well as having the potential to introduce variability into

the ﬁ eld (Hepton, 2003). Time from planting to harvest is dependent primarily

on the weight of the propagule, and crowns produce fruit in 18–24 months,

slips in 15–20 months and suckers in 12–17 months. Planting materials are

treated with a fungicide or are ‘air-cured’ by drying the butt end, or both,

before planting to prevent rots.

A shortage of planting material can occur when fruits are sold fresh,

because the fruit is usually marketed with the crown. Most commercial clones

of ‘Smooth Cayenne’ produce only one to two suckers per plant and seldom

more than three slips. Several techniques are available to speed up propagule

production required for variety and clone development or to replace planting

material sold with the fruit. Cost of labour often determines which techniques

are used.

Stem sectioning utilizes the axillary buds, usually on stems of mature

plants. Leaves are stripped o the stem; the stem is quartered longitudinally

and each quarter is divided into sections approximately 5 cm in length. The

sections are immersed in a fungicide solution or air-cured for several days, or

both, before planting in well-prepared nursery beds with good drainage and

aeration. Shoots that grow from axillary buds can usually be transplanted in

4–6 months. A normal-sized ‘Smooth Cayenne’ plant stem can produce an

average of 25 sectioned plants (Collins, 1960). Established crowns and shoots

with adequate root systems can be split longitudinally into quarters, which

forces one to several axillary buds to develop. These small plants (plantlets)

can be transplanted when large enough and the process repeated. A similar

technique is to gouge out the plant’s apical meristem, thereby breaking apical

346 Chapter 12

dominance over axillary buds. One to a few suckers are produced, which,

when harvested, result in the production of additional suckers. Once plant

reserves are exhausted, a sucker can be allowed to grow and gouged when of

reasonable size, resulting in the production of additional suckers. In Okinawa,

crown leaves planted in sand produce plantlets at the leaf base. Only one

plantlet is produced per leaf at a low rate. As no axillary buds are present on

the leaf, shoots must be generated from meristematic callus formed at the leaf

base tissue or from stem tissues adhering to the leaf base. From 40 to 70 leaf-

bud cuttings can be produced from a single crown.

Plantlet production is induced by treating plants with the morphactin

chloroﬂ urenol (Maintain CF-125

; Multiprop R

) after reproductive develop-

ment has been forced with ethephon. Chloroﬂ urenol is applied 1 or 2 days after

forcing and before signiﬁ cant ﬂ ower di erentiation has occurred. If timing and

concentration of chloroﬂ urenol are appropriate, up to ten good-sized plantlets

are produced (Hepton, 2003). Plantlets have also been produced by meristem

culture, but care must be taken to prevent excessive somaclonal variation. It

is reported that up to one million plants can be produced from a single bud in

2 years through tissue culture, but this technique is generally more expensive

than other propagation techniques.

Field preparation and layout

The ﬁ rst step in ﬁ eld preparation on an established pineapple farm is the

destruction of existing plants, since pineapple can be a serious weed if live

plants are plowed under. The fresh plant mass in a ratooned pineapple ﬁ eld is

huge, and residue incorporation or disposal is a costly step in ﬁ eld preparation.

Plants usually are disced multiple times or chopped to hasten desiccation,

and when thoroughly dried are plowed under or burned. The decision as to

whether to plow or burn is often determined by how soon the ﬁ eld is scheduled

for replanting. Conventional tillage implements are used for primary land

preparation on most pineapple farms and plantations, though in Hawaii, a

teﬂ on-coated moldboard plow was developed that would scour in clay soils and

that permitted ﬁ elds to be plowed to a depth of more than 80 cm. Deep plowing

aids in the incorporation of the large amounts of plant residues produced by a

pineapple crop. Except where deep plowing is done, the size of equipment used

is determined mostly by farm size. Where the soil is compacted, subsoiling is

desirable to break the hard pan to improve drainage and soil aeration. Discing

to break up soil clumps and improve soil texture is important to improve

dispersion of fumigants and to provide good plant-to-soil contact.

Black polyethylene mulch (∼50 microns thick and 81 cm wide) helps to

prevent rapid escape of fumigants, maintains warmer soil temperatures during

the cool season, retains moisture at the soil surface, reduces fertilizer leaching

during rainy periods, controls weed growth in the beds and increases yield. In

Pineapple 347

many pineapple-growing areas where plastic mulching is too costly, mulching

with straw, grass, sugar cane baggasse or other available materials is done.

Crop rotation for nematode control is a possible practice when economical.

Fumigation

‘Smooth Cayenne’ is susceptible to several plant parasitic nematodes, which

if left unchecked can devastate the plant. Pre-plant fumigation of the soil

with a volatile nematicide to control root-knot and reniform nematodes is an

established practice in Hawaii. In recent years, loss of some fumigants has

occurred due to health and environmental concerns. Non-volatile nematicides

are applied post-planting through drip irrigation systems, to provide nematode

control later in the plant crop and during ratoon crop development. Even

with signiﬁ cant nematode feeding pressure, it is often possible to produce an

acceptable mother-plant crop. However, under such pressure ratoon crop

growth and yield will probably be severely reduced, possibly to the point of

complete ratoon crop failure, because ratoon yields are highly dependent upon

the health of the plant crop root system. In South Africa, where Meloidogyne

and Helicotylenchus nematodes are serious problems in pineapples, pre-plant

dipping in a systemic nematicide followed by post-plant spraying at monthly

intervals for 12 months increases a plant crop yield by 11 t/ha. In the absence

of any history of nematode problems, soils should be assayed for nematodes

before embarking on costly nematode control programmes.

Planting

Planting is commonly done manually with a 25 cm-long, trowel-shaped

planting tool. Good soil preparation makes it easy to place the propagule deep

enough into the soil to assure good plant-to-soil contact. Marked cords may

be stretched from one end of the ﬁ eld to the other to keep rows aligned and to

indicate plant spacing. In Hawaii, spacing is established by factory marking on

polyethylene mulch. In Queensland, Australia, South Africa and Mexico, some

growers use a planting machine similar to a vegetable transplanter.

Crowns, slips and suckers are planted separately in di erent ﬁ elds.

Crowns are smaller than and somewhat more uniform in size than slips and

suckers. Slips and suckers can be large, with size mostly determined by the

length of time they remain on the plant. Sizing prior to planting is crucial

in order to obtain uniform-sized plants at the time of ﬂ oral forcing, to assure

a uniform-ripening fruit crop (Py et al., 1987). Large suckers have a high

tendency for precocious fruiting, being physiologically mature, especially

when sucker weight exceeds 600 g. The following weight classes are

348 Chapter 12

suggested (Py et al., 1987): small crowns 100–200 g and medium crowns

200–300 g, and slips or suckers small 200–300 g, medium 300–400 g and

large 400–600 g.

Spacing

Plant spacing or density a ects pineapple average fruit weight and yield per

unit area (Fig. 12.8). Plant density and other cultural practices for ‘Smooth

Cayenne’ are directed towards the production of a fruit size appropriate to the

principal use: the fresh fruit markets or processing. Spacing is also dependent

upon cultivar. Cultivars of the Spanish group produce smaller plants but have

spiny leaves, so wider spacing is used than for smooth-leaved cultivars (Fig.

12.8). On small farms, growers may use a single-row system with relatively

wide spacing between plants and between rows, giving plant densities of

15,000–25,000 plants/ha. In commercial plantings, a double-row system

has been widely adopted, although three- and four-row systems also are fairly

common. Multiple-row systems allow for increased planting density but may

make harvesting operations more di cult and require good management to

assure plant requirements are met. In the conventional two-row bed system,

various spacing regimes are employed to achieve desired plant densities. In

areas where plastic mulch is used, changes in bed width are limited by the

width of mulch used. The spacing between plants in a row should not be less

than ~20 cm, and spacing between rows in a two-row system would be about

35 cm, with between 90 and 120 cm from bed centre to bed centre. Planting

densities typically range from 60,000 to 80,000 for ‘Smooth Cayenne’ and

hybrids with similar growth habit (Fig. 12.8). When plants of the same size

are forced, average fruit size decreases linearly as planting density increases,

with the extent of the decrease being determined by cultivar and environment

(Hepton, 2003). Planting densities as high as 75,000 plants/ha are used

where smaller fruits are desired. There is a fruit size decrease of about 45 g for

each population increase of about 2500 plants/ha.

Irrigation

The pineapple has a low water requirement and can survive long periods

of water stress under natural conditions. However, under non-irrigated

conditions yields are low, with poor-quality fruit of unacceptable size.

Irrigation of pineapple in the Ivory Coast increased yields by 14–22 t/ha,

with a cost equivalent to a yield of 5 t/h. The potential evapotranspiration

of pineapple can reach 4.5 mm per day and a soil’s water-holding capacity

rarely exceeds 100 mm, so without rains, the water supply will be exhausted

within 3 or 4 weeks. Water deﬁ cits can be indexed by the relative thickness

Pineapple 349

of the water-storage tissue of the youngest, physiologically mature leaf

(D-leaf) and by the percentage of white root tips visible on the roots in the soil

(Sanford, 1962).

Irrigation allows year-round planting, allows plants to attain a desirable

plant size for forced ﬂ ower initiation at scheduled times of the year and for

harvesting on a ﬁ rm schedule, allows the use of soils with poor water retention

and allows fertilizing even during the dry season (Fig. 12.7). Weed problems

are, however, increased by overhead irrigation. Sprinkler delivery systems,

including a self-propelled boom sprayer, have been used. Drip irrigation has

replaced other methods of irrigation in most ﬁ elds in Hawaii, with one tubing

oriﬁ ce for every two plants. The quantity of water applied is low compared

with most other crops, typically being in the range of 1.5 cm/ha/week. Drip

irrigation allows fertilizers and nematicides to be applied at the root system

after planting with increased e ciency and safety, and yields are increased.

Fig. 12.8. Effect of planting density on fruit weight (a) and fruit yield (b); data are

for ‘Queen’ grown in Ghana, ‘Singapore Spanish’ grown in Malaysia and ‘Smooth

Cayenne’ grown in Queensland and Swaziland (from Hepton, 2003).

350 Chapter 12

Yield increases have been especially evident in ratoon crops, due to a decrease

in plant mortality and the healthier condition of the plants at plant crop

harvest. The healthy condition of the ratoon plants is due primarily to frequent

delivery of nematicides.

Fertilization

Various published reports on pineapple nutrition indicate that the quantity

of N required ranges from 225 to 350 kg/ha. The requirements for the other

major fertilizer elements are best determined by soil analysis (Malezieux and

Bartholomew, 2003). If K is required, the amount applied usually ranges

from 225 to 450 kg/ha. The crop has a low requirement for P, and 20 ppm of

P in soil is considered adequate. The P requirement can be met by pre-plant

application of this element, and usually from 20 to 80 kg/ha is applied, as

P, P

or, in acid soils, rock phosphate. Some idea of pineapple fertilizer

requirements may be obtained by analyses of elements immobilized in the

various plant parts (Table 12.2). Large amounts of N and K are found in the

plant, fruit and slips. In ratoon ﬁ elds, which develop on suckers on the mother

plant, nutrients removed by the ﬁ rst fruit crop must be replenished. This

amounts to approximately 175 kg N, 27 kg P, 336 kg K, 47 kg Ca and 27 kg

Mg per hectare.

Pineapple responds well to foliar fertilization, and nitrogen, boron,

iron, zinc and sometimes potassium are applied this way (Malezieux and

Bartholomew, 2003). While almost any inexpensive fertilizer can be used,

urea and UAN32 are commonly applied as foliar sprays on a weekly or

biweekly basis, from about 3 months after planting. Urea can be applied as a

foliar spray at up to 20% concentration without damage, if the biuret is less

than 1%. Iron nutrition is a problem in the Hawaiian pineapple soils due to

the high manganese content. The Fe/Mn ratio is more critical than the level

of either nutrient alone (Py et al., 1987). Ferrous sulfate at up to 17 kg/ha per

application is given, as needed, as a foliar spray. Plants with Fe deﬁ ciency show

yellowing of inter-veinal areas. However, Fe deﬁ ciency also a ects absorption

Table 12.2. Minerals immobilized or removed by pineapple plants at a density of

54,340 plants/ha.

Amount immobilized or removed from plant (kg/ha)

NP K CaMg

Plant 437 47 538 134 134

Fruit 135 20 269 33.6 20.2

Slip 40 6.7 67 13.4 6.7

Total 612 73.7 874 181 160.9

Pineapple 351

of N, via its e ects on the root system, leading to a general yellowing of the

entire plant. Zinc deﬁ ciency is usually found in eroded areas, in soils with

high amounts of coral sand and in soils with high pH. Deﬁ ciency causes the

younger leaves to curve and twist; the symptom is unique and diagnostic.

When Zn deﬁ ciency is severe, apical dominance is lost and plants sucker

profusely. Zinc sulfate 0.5% (w/v), applied at 935 l/ha, is sprayed as needed.

Boron deﬁ ciency is characterized by chlorosis of young leaves, development

of red margins and even death of the apical region, resulting in profuse

suckering. Boron deﬁ ciency is a common problem in Australia and 1–4 ppm

boron is applied with ethephon at the time of forcing.

The nutrient requirements of pineapple in Hawaii are based on the

concept of the crop log, which involves the development of laboratory soil and

foliar indices, visual deﬁ ciency symptoms for N, Fe and Zn, and others that

measure growth rate, pathogens, root parasites, moisture stress and weather

conditions (Sanford, 1964; Malezieux and Bartholomew, 2003). A crop log

not only indicates deﬁ ciency symptoms but also attempts to determine causes

of deﬁ ciencies. Soil and foliar analyses are both important, as the former

shows reserve amounts of soil nutrients and the latter indicates e ciency in

absorption. An element may be su cient in the soil but deﬁ cient in the plant,

due to causes such as moisture stress, root disease or loss of the root system to

pests, or an elemental imbalance causing unfavourable interactions a ecting

absorption (Sanford, 1962). Fertilizer is applied on a schedule to meet di erent

requirements at di erent stages of growth (Table 12.3). Foliar applications

should cease after forcing to prevent injury to the inﬂ orescence and reduced

fruit yields.

Chemical ﬂ ower induction

The accidental discovery in the Azores that smoke from burning organic

materials induces premature ﬂ owering in greenhouse-cultured pineapples

led to the wide practice of burning rubbish around the periphery of the

ﬁ elds in Puerto Rico (Rodriguez, 1932). The active ingredient in the smoke

is ethylene gas, with acetylene and calcium carbide also inducing ﬂ owering

in pineapple (Aldrich and Nakasone, 1975). Forcing plants into ﬂ owering

allows synchronization of harvest and makes it possible to control harvest

dates to meet anticipated fresh market and cannery needs (Fig. 12.7). Fruit

harvest date can be predicted with good accuracy with only daily maximum

and minimum air temperature to calculate fruit heat units (Malezieux et al.,

1994). This model can be adjusted using historical data.

The relatively soluble sodium salt of alpha-naphthaleneacetic acid (SNA)

was the ﬁ rst plant growth regulator used commercially to force ﬂ owering

in Hawaii (Bartholomew and Criley, 1983). Ethylene and acetylene gases

dissolved in water have been used in many pineapple-growing regions. The

352 Chapter 12

gases require specialized equipment for e ective application and safe use.

In the warm tropics, SNA has not been e ective, while a water solution of

acetylene produced from calcium carbide or calcium carbide as granules has

been successful.

Ethephon (2-chloroethylphosphonic acid) is probably the most widely

used chemical in commercial pineapple production because of its e ectiveness

and ease of application. This chemical breaks down to produce ethylene

at neutral pHs (Bartholomew and Criley, 1983). The e ective ethephon

concentration ranges from 500 to 1500 μg/l, with greater amounts required

to force ﬂ owering in warm than in cool months. At least 90% ﬂ owering is

obvious 40–60 days after applying about 1000 μg/l solutions (Fig. 12.7) with

50 kg/ha urea (Bartholomew, 1977). In some regions, adjusting the solution

pH above 7 with sodium borate improves forcing success.

Acetylene and ethylene are less e ective when applied during the day

but highly e ective when applied at night or during the early morning hours,

when the stomates are open (Bartholomew and Kadzimin, 1977). In warm

seasons, forcing success may be greater on days when temperatures are less

than 30°C. High N level in the plant at the time of forcing may further reduce

forcing success in warm weather, while withholding nitrogen fertilizer for 4–6

weeks before forcing can improve induction. Plants approaching the natural

Table 12.3. Fertilizer protocol for pineapple planted at 58,710 plants/ha, applied

using a spray valve of 2500 l/ha for different stages of plant development (after Evans

et al., 1988).

Stage of development (month)

0 0–3 4–8 9–10 11–12

Stage Prior to

planting

Growing Growing Growing Forcing

Method Into soil Foliar Foliar Foliar Foliar

Number of

applications

1352 2

Desired crop

colour

Pale yellow

green

Darker

yellow

green

Dark

green

All green

Fertilizer Rate (kg/ha/application)

Total

(kg/ha/

year)

Urea 22 22 33 45 55 450

Potassium nitrate 22 22 33 45 55 450

Iron sulfate 1.5 1.5 2.25 3.0 3.70 30

Zinc sulfate 0.5 0.5 0.75 1.0 1.25 10

Magnesium sulfate 2.75 2.75 3.75 5.5 6.75 55

Pineapple 353

period of ﬂ owering show greater susceptibility to induction (Fig. 12.9a), as

smaller plants are not as susceptible to natural ﬂ owering and are not as easily

forced to ﬂ ower. The minimum size for forcing is much larger under optimum

growing conditions than when growth is restricted by nutrient, water or low-

temperature stress. Plant weights are used to estimate suitability for forcing,

as the larger the plant weights at forcing the bigger the fruit harvested (Fig.

12.9b). For ‘Smooth Cayenne’, when the plant fresh weight is between 2 and

4 kg the ﬁ eld will be forced to ﬂ ower, depending on plant growth status and

weather. Ratoon suckers are more easily induced to ﬂ ower than the plant crop.

The Spanish group is also easier to force in conditions impossible for Cayenne.

Pest management

Except for small plantings in subsistence-farming systems, pineapple is

largely a monocultured crop, involving relatively large ﬁ elds under more or

less standardized cultural practices. Monoculture, as well as the perennial

nature of the crop, is conducive to accumulation of diseases and pests, some

conﬁ ned to certain regions, while most have become established worldwide

(Lim, 1985; Rohrbach and Schmitt, 1994) as vegetative germplasm has been

transported around the world since the 1600s. The ‘Smooth Cayenne’ cultivar

is relatively resistant to most pineapple diseases (Rohrbach and Johnson,

2003). Occasionally, damage associated with speciﬁ c pests or diseases can

cause serious economic losses.

Diseases and nematodes

One of the most important diseases worldwide is mealybug wilt (Table 12.4).

This wilt is caused by a closterovirus and associated feeding by the mealybugs

Dysmicoccus brevipes and Dysmicoccus neobrevipes (Sether and Hu, 2002), both

of which are able to transmit the virus; the disease does not occur if only the

closterovirus or the mealybugs are present. Ants, which protect the mealy

bug colonies and transport individuals from plant to plant, also are essential

to disease development. The dominant species of ant on pineapple in Hawaii

and in South Africa is the big-headed ant (Pheidole megacephala). Ant control

is essential to the control of mealybugs and the wilt; in the absence of ants,

parasitoids and predators keep mealybugs under control. Mealybugs feed on

the roots, on the stem above the roots, on leaf sheaths or leaves and in fruitlet

ﬂ oral cavities. Wilt-a ected plants are stunted, becoming yellowish ﬁ rst and

reddish later. These symptoms resemble the e ects of severe drought.

Some pineapple cultivars possess partial resistance to the mealybug

wilt. However, the only practical control of mealybugs and the associated

ants is by use of insecticide baits to control the ants. Cultivation eliminates

mealybugs, and in a newly planted ﬁ eld they gradually move into the ﬁ eld

from uncultivated grassy or weedy borders, where mealybugs survive on

354 Chapter 12

Fig. 12.9. Effect of plant age (a) on susceptibility to natural ﬂ owering (redrawn from

Lacoeuilhe, 1975), and plant weight (b) at forcing and fruit weight at harvest for

‘Smooth Cayenne’ (from Bartholomew et al., 2003).

Pineapple 355

Table 12.4. Some important diseases and nematodes of pineapple.

Common name Organism(s) Parts affected and symptoms

Region or country of

importance

Mealy bug wilt Viral Plant Universal

Pink disease

Gluconobacter oxydens

Acetobacter aceti

Erwinia herbicola

Dark brown discoloration of infected fruit ﬂ esh

upon heating

Hawaii, Australia, Philippines

Interfruitlet corking

Penicillium funculosum

Fruitlets Hawaii

Leathery pocket

Penicillium funculosum

Fruitlets Hawaii, South Africa

Fruitlet core rot

Penicillium funculosum

Fusarium moniliforme

Fruitlets

Pineapple butt rot

Chalara paradoxa

Stems of planting material, and fresh fruit rot Universal

Root/heart rot

Phytophthora cinnamomi

Phytophthora nicotianae

Root, plant, fruit Universal

Root knot nematode

Meloidogyne javanica

Galls, root destruction, stunts plant Universal

Reniform

Rotylenchulus reniformis

No galls; destroys lateral root system, retards

growth

Universal

Root lesion

Pratylenchus brachyurus

Lesion on root and destruction Universal

Root lesion

Rotylenchulus unisexus

Root destruction South Africa

Spiral

Helicotylenchus dihystera

Root destruction Ivory Coast, South Africa,

Puerto Rico, Hawaii

356 Chapter 12

alternate hosts. Movement from ﬁ eld edges led to a practice of planting several

beds of pineapple in a strip parallel to the edge of the ﬁ eld and separated from

the main ﬁ eld by a road as a bu er. These bu ers were sprayed regularly. Ant

control using baits is more common in Hawaii.

Heart and root rot caused by P. cinammomi Rands and P. nicotianae

B. de Haan var. parasitica Dast, Waterh. and P. palmivora (Butler) Butler

does not occur uniformly and levels of infection can vary from year to year.

P. cinammomi is virulent in cooler conditions while P. nicotianae and P. palmivora

are associated with warmer and more tropical environments. Conditions

conducive to Phytophthora rots include poorly drained soils, high rainfall and

a soil pH above about 5.5. Crown plantings, especially during the wet season,

are highly susceptible to Phytophthora rots, with the loss of 30–100% not being

uncommon. The disease is controlled by pre-plant dips of planting materials

and by foliar post-plant spray using fungicides.

Butt or black rot is a universal problem of stored planting material and

of fresh fruit. The disease, caused by Chalara paradoxa (De Seynes) Sacc, is

characterized by a soft rot and blackening of the basal portion of the stem

of vegetative propagules, and similar symptoms are seen on infected fruit.

Infected propagules can completely decay if kept moist, and an infection can

quickly spread through an entire pile. In the absence of fungicide treatment,

planting material can be protected by air-curing for several days. Fruit rot is

managed by careful handling of the fruit to avoid bruising, by refrigeration

and with a fungicide dip. Infection occurs within 8–12 h following wounding.

Susceptibility varies with the cultivar, ‘Red Spanish’ types being more resistant

than ‘Smooth Cayenne’.

Other fruit diseases – fruitlet core rot, interfruitlet corking, pink disease

and marbling disease – are universally distributed and occasionally can be

important. Brown rot or fruitlet core rot occurred in only 7% of inspected

fruit. Other postharvest pineapple diseases that begin prior to harvest may

cause sporadic economic problems.

Nematodes are a serious problem wherever pineapple is grown on the

same land over many years. Yield losses of one-third are common in the plant

crop, with total failure in the ﬁ rst ratoon crop without nematode control.

Injury caused by nematodes feeding on the roots is compounded by the roots

non-regenerative nature. Fumigants do not completely eradicate nematodes.

Eggs and dormant larvae are harder to kill, repopulating the soil with time and

necessitating periodic post-plant application of nematicides. For maximum

e ciency of fumigants, soil must be well prepared, with deep ploughing and

the breaking of all clods. Too much soil moisture inhibits good dispersion of

the fumigant in the soil, while fumigant escape is rapid when the soil is too

dry. Polyethylene mulch over beds helps to retain volatile fumigants in the

soil. Application of nematicides by drip irrigation is e ective in controlling

nematodes, particularly in the ratoon crop.

Pineapple 357

Pests

Insects can cause direct damage to various plant parts or vector diseases

(Table 12.5). Prior to 1953, pineapple fruit were fumigated with methyl

bromide before importation into continental USA. Pineapple fruits that are

more than 50% ‘Smooth Cayenne’ are not now regarded as a host for tephritid

ﬂ ies: Mediterranean fruit ﬂ y, C. capitata (Wiedermann); the Melon ﬂ y, D.

cucurbitae (Coquillet); and the Oriental fruit ﬂ y, D. dorsalis Hendel; hence, insect

disinfestation is no longer required (Armstrong and Vargas, 1982).

The pineapple scale, Diaspis bromeliae (Kerner), occurs wherever pineapple

is grown. In Hawaii, pineapple scale is not normally a major problem in

ﬁ elds, probably because of scale parasites and predators. However, because

of the US quarantine requirement, fruit have to be insect-free, and even low

levels of pineapple scale at harvest present quarantine problems. Scale can

be controlled relatively easily by preharvest insecticide applications, taking

into consideration label requirements relating to last application prior to

harvest time.

The pineapple fruit mite, Steneotarsonemus ananas Tryon, occurs uni-

versally on the growing plant, developing inﬂ orescence, fruit and crown. The

fruit mites feed on developing trichomes on the white basal leaf tissue and

ﬂ ower bracts and sepals, causing light brown necrotic areas. The pineapple red

mite, Dolichotetranychus ﬂ oridanus Banks, feeds on the white basal leaf tissue,

particularly of the crown. Severe damage occurs when the fruits mature under

drought conditions, and it may cause death of the basal crown leaves, thereby

a ecting fruit quality (Rohrbach and Schmitt, 1994).

Other insects are mentioned frequently in the literature. In Latin America

and in some Caribbean islands the larvae of the Thecla butterﬂ y (Thecla

brasiliodes) cause fruit damage, occasionally in serious proportions. Dusting

or spraying the fruit at ﬂ owering stage with appropriate insecticides has given

satisfactory control. In the Caribbean region, the larvae of the Batrachedra

butterﬂ y (Batrachedra sp.) damage fruit at the ﬂ owering stage, causing

gummosis. Field observations in Jamaica during 1972 showed high incidence

of damage in ‘Red Spanish’ but not in ‘Smooth Cayenne’.

Weed control

Weeds can cause serious crop losses, and on small farms, neglect of weeding at

monthly intervals can result in 20–40% declines in yields. Average fruit weight

in Guinea can be 0.60 kg from an unweeded ﬁ eld, as compared to 1.55 kg with

good weed control. Weed control is a major cost item in pineapple production

and is essential to assure high yields as well as removal of plants that host or

harbour nematodes and insects such as mealy bugs. The weed problem can be

lessened by complete mulching of the beds and interbeds, hence delaying or

358 Chapter 12

Table 12.5. Some important insect pests of pineapple.

Common name Organism Parts affects and symptoms Region or country

Bigheaded ant

Pheidole megacephala

Associated with mealybugs and wilts Hawaii

Ants

Solenopsis sp.

Anaucomyrmex sp.

Associated with mealybugs and wilts Guyana

Pineapple scale

Diaspis bromeliae

Leaves, fruit Universal

Souring beetle (pineapple

beetle)

Carpophilus humeralis

Plant, ripe fruit Universal

Mealybug

Dysmicoccus brevipes

Roots, stems, leaves Universal

Pineapple fruit mite

Steneotarsonemus ananas

Tryon

Developing inﬂ orescence, fruit and crown Universal

Pineapple red mite

Dolichotetranychus

floridanus Banks

Feeds on the white basal leaf tissue, especially

crown

Universal

Black maize beetle

Heteronychus arator

Lower stems and roots South Africa

White grub

Several beetle species

Root system South Africa

Thrips

Thrips tabaci

Yellow spot disease (virus transmitted by thrips

from Emilia sonchifolia)

Hawaii, other areas

Batrachedra butterﬂ y

Batrachedra methesoni

Fruit at ﬂ owering stage causes gummosis, larvae

causes damage

Caribbean

Thecla butterﬂ y

Thecla brasiliodes

Fruit at ﬂ owering stage causes gummosis, larvae

causes damage

Mexico

Central America

South America

Caribbean

Symphylids

Hanseniella unguiculata

Root tips, severe stunting Universal

Pineapple 359

minimizing weed growth. Polyethylene sheet mulching of beds substantially

alleviates weeding within beds.

Weed control in commercial plantations is achieved by chemical means,

unless labour is abundant and inexpensive. Chemical weed control is e cient

and rapid if done correctly at appropriate times, using mechanical applicators.

Pre-emergence application, either before or immediately after planting, is low

in cost and e ective. For herbicides, as with other agricultural biocides, there

usually are restrictions on timing of applications and limits to the quantity

that can be used per hectare, per crop cycle or per year.

HARVESTING AND POSTHARVEST HANDLING

Harvesting

Prior to the use of chemicals to induce ﬂ owering, many passes were required

to complete harvesting of a large ﬁ eld, due to the wide variation in time of

ﬂ owering during the winter season, when most ﬂ ower induction occurred.

Chemical induction concentrated the period of ﬂ owering, therefore

condensing harvesting to two to three passes (Paull and Chen, 2003). Natural

or precocious ﬂ owering during cool weather with short days can signiﬁ cantly

disrupt harvesting and marketing schedules. In Hawaii, fruit developing from

precocious ﬂ owering in some years leads to a second peak, followed by a mid-

year dip in production (Fig. 12.10).

Controlled ripening of fruit with ethephon prior to harvest can further

reduce the number of harvesting passes. Ethephon is applied 48 h or more

before harvest to accelerate shell degreening (Soler, 1992). This accelerated

shell degreening is due to destruction of chlorophyll, giving the shell a

more uniform colour. The application should occur when natural colouring

has started, to assure good fruit quality, and is sometimes less e ective in

hot weather.

Fruits destined for the cannery are usually harvested at the half- to three-

quarter-yellow stage. Fruit to be transported to distant fresh fruit markets is

picked anywhere from mature green (no yellow colour) to quarter-coloured

stage. Fruit maturity is evaluated on the extent of fruit ‘eye’ ﬂ atness, skin

yellowing and acidity to total soluble solids (TSS) measurements. Consumers

similarly judge fruit quality by skin colour and aroma. A minimum reading

of 12% total soluble solids (

Brix) is required for fresh fruit in Hawaii, while

others have suggested 14%. A sugar to acid ratio of 0.9–1.3 is recommended

(Soler, 1992).

Pineapple for the fresh market is hand harvested, with pickers being

directed as to stage or stages (shell colour) of ripeness required. Fruit is

packed either in the ﬁ eld or at a central packing shed. In Hawaii, pickers walk

360 Chapter 12

in the inter-rows and place the fruit on a conveyor belt running on a boom,

which transfers the fruit to a truck ﬁ eld bin. Fruit is placed in the bin by hand,

upside-down on the crown to avoid injury. Fruits are also harvested by pickers

carrying large baskets on their backs. When the baskets are full, the fruits are

dumped at the ends of the rows or at the side of ﬁ eld roads, to be later loaded

into trucks or trailers. When the fruit arrives at the packing shed, it is unloaded

by hand, by submerging the ﬁ eld bin in water or by sliding the fruit out of the

ﬁ eld bin into water. Fruit with high translucency (‘sinkers’) are separated at

this step. Fully ripe, translucent fruit are unsuitable for transporting to distant

markets and less-mature fruit are selected. Immature fruits are not shipped,

since they do not develop good ﬂ avour, have low sugars, and are more prone to

chilling injury. Care is taken to avoid mechanical damage to the crown leaves

and mechanical injury to the fruit shell.

Postharvest handling

Fruits are waxed after washing, frequently with polyethylene and para n or

carnauba and para n waxes. The selected wax reduces internal browning

Fig. 12.10. The effect of precocious ﬂ owering in the January to February period on

outshipment of pineapples from Hawaii contrasted with desired production.

Pineapple 361

symptoms of chilling injury, reduces water loss, improves fruit appearance and

assures a more even application of fungicide used to control rots (Paull and

Rohrbach, 1985; Paull and Chen, 2003). There is no worldwide uniformity in

acceptance of wax components, so importing-country restrictions need to be

considered. If the wax injures the crown leaves, only the fruit body is waxed.

Postharvest fungicide is normally included in the wax.

Fresh fruit quality standards are based upon recognized appearance

characteristics (Table 12.6). The fruit needs to be mature, ﬁ rm, well formed,

free of defects, have ﬂ at eyes and a minimum soluble solids of 12% in Hawaii.

Crown size is a crucial grade component, with a minimum size and a set ratio

of crown to fruit length (0.33–1.5) for the higher grades. Crowns that develop

during the summer in Hawaii tend to be larger and may require ‘gouging’

at harvest to meet the standard. This ‘gouging’ leaves a wound for possible

disease entry and detracts from overall appearance. ‘Gouging’ 2 months

before harvest to limit crown growth avoids visible scarring. Fruits are graded

by degree of skin coloration, size (weight), absence of defects and disease, and

other market needs before packing (Soler, 1992).

Temperatures in the range 7.5–12°C are recommended for storage, with

relative humidity of 70–95%; the higher humidity signiﬁ cantly reduces water

loss. At a temperature of 0–4°C, the fruit may be stored for weeks, but upon

removal, the fruit fails to continue ripening and shows severe chilling injury

(Paull, 1993). Half-ripe ‘Smooth Cayenne’ fruit can be held for about 10

days at 7.5–12.5°C and still have about a week of shelf-life, with no chilling-

induced internal browning.

Table 12.6. USA fresh pineapple fruit standards. All grades have 10% limits on

defects, 5% on serious damage and 1% on decay.

Standards

Varietal

character-

istics Maturity Free from Slips knobs

Crown to fruit

length ratio

US Fancy Similar Mature, ﬁ rm,

dry, well

formed, well-

developed

eyes

Decay, sunburn,

injury,

bruising, well-

cured butt

Single

crown,

no slips

Ratio less than

1.5, not less

than 12 cm

in size

US #1 Similar Mature, ﬁ rm,

dry, well

formed, well-

developed

eyes

Decay, sun-

burn, injury,

bruising, fairly

well-cured

butt

<5 Slips Ratio less than

2.0 and

greater than

10 cm in

size

US #2 Similar Mature, ﬁ rm,

dry, fairly

well formed

eyes

Serious decay,

sunburn,

injury, bruising

Slips Any ratio,

double

crown

362 Chapter 12

Physiological disorders

Chilling injury

The maximum storage life of pineapple at 7°C is about 4 weeks; however, when

removed, chilling injury develops within 2–3 days. The symptoms of chilling

injury (CI) include: (i) wilting, drying and discoloration of crown leaves; (ii)

failure of green-shelled fruit to yellow; (iii) browning and dulling of yellow

fruit; and (iv) internal ﬂ esh browning (Paull and Rohrbach, 1985). Preharvest

shading and pre- and postharvest low temperatures are the major factors

increasing CI symptom intensity. CI symptoms have been called endogenous

brown spot, physiological breakdown, blackheart and internal browning.

Postharvest CI symptoms develop after fruits are returned to physiological

temperatures (15–30°C). Susceptible fruits are generally lower in ascorbic acid

and sugars and are opaque (Teisson, 1979a,b). Partial to complete control of

CI symptom development has been achieved by waxing, polyethylene bagging,

heat treatments, controlled atmospheres and ascorbic acid application.

Flesh translucency

Flesh translucency increases fruit sensitivity to mechanical injury. This

condition begins before harvest and continues after harvest. TSS, ﬂ esh

pigments and palatability increase to a maximum at about 60% translucency,

then decrease in fruit with greater translucency. Translucency is more severe

and has a higher incidence when maximum and minimum temperatures

3 months before harvest are both low, less than 23 and 15°C or, to a lesser

extent high, greater than 29 and 20°C, respectively. Fruit with a larger crown

has a lower incidence and severity of translucency (Paull and Reyes, 1996).

Bruising

Fruit bruising is a major problem during harvesting and packing. Bruising can

be caused by impact damage, a 30 cm drop causing signiﬁ cant damage. This

injury is normally conﬁ ned to the impact side of the fruit. The damaged ﬂ esh

appears slightly straw-coloured. Mechanical injury of translucent fruit can

lead to leakage of fruit cell contents and loss of marketable fruit.

Sunburn

Sunburn is common during hotter periods (>35°C) of the year, when the fruit

is not shaded by leaves and especially in ratoon crops. The condition is more

prevalent in the outer rows and when fruit is lodged. Sun-scorched fruit ﬁ rst

show a bleached yellow-white skin, which turns pale grey and brown, with

damage to the ﬂ esh underneath. These damaged areas are more susceptible to

disease organisms, particularly yeasts and bacteria.

Pineapple 363

Malformations

Knobs on the base of fruit occur in o -types. Culling of the crowns of these

fruits as planting material reduces the subsequent ﬁ eld incidence. These fruits

are not marketed, since trimming generally breaks the fruit skin and allows

rots to develop. The other genetic o -type is multiple crowns (fasciation), two

or more on each fruit, with the fruit taking on a ﬂ attened appearance. This

condition is often related to high-temperature injury after forcing. These

fruits should not be marketed and crowns should not be used for planting.

Fruits with pronounced ‘eyes’ or fruitlets normally do not meet most grade

standards, and the thicker skin means lower ﬂ esh recovery. This condition is

common in fruits that ﬂ ower during cool weather. Some ‘Spanish’ varieties

are susceptible to broken core, in which the central fruit core has a transverse

break, leading to the upper part of the fruit ripening ahead of the bottom.

UTILIZATION

Pineapple does not sweeten after harvest, though the acid level may

decline. Canning is more successful with an acid fruit, as a lower processing

temperature can be used (Hepton and Hodgson, 2003). Because canned

product can be stored for long periods without deterioration, fruits destined

for canning tend to be harvested during the summer months, when fruit

quality is highest. The sugar to acid ratio varies widely with cultivar, growing

condition and stage of harvest from 80 to 200. Ascorbic acid also varies widely

with cultivar from 2.5 to 180 g/kg FM of ﬂ esh. Pineapple is a good source

of ascorbic acid (vitamin C), some vitamin A, calcium, phosphorus, iron,

potassium and thiamine. It is low in sodium (Table 12.7).

Most fruit produced goes into the fresh fruit market (Fig. 12.11), mostly

to markets within a country. Much of this fruit is not recorded in world

production ﬁ gures. There is an increasing interest in minimally processed

pineapples, with the shell and core removed just before purchase. The major

processed products are canned slices or solid pack, with a recovery percentage

varying from 20% in ‘Singapore Spanish’ to ca. 60% for ‘Smooth Cayenne’.

Cans of several sizes are ﬁ lled with the best slices. Uncanned and broken slices

are packed as chunks, tidbits or crush (Fig. 12.11). Flesh remaining on the

shell, cut ends, core and trimmings are processed into juice. Much of the juice

is now concentrated, with the volatile ﬂ avour components being recovered

and added back to the concentrate, and frozen to maintain a higher ﬂ avour

quality than the single strength. Shipping costs for the concentrate also are

greatly reduced relative to those for single-strength juice. The residue of the

juice recovery stream is processed into animal feed or other by-products. This

residue from pressed fruit shells and pulp has been sold to dairy farms either

wet or dried (Fig. 12.11).

364 Chapter 12

Table 12.7.

Proximate analysis of ‘Smooth Cayenne’ fruit (Wenkam, 1990).

Amount per 100 g

edible portion

Water (g) 86

Energy (kJ) 218

Protein (g) 0.5

Lipid (g) 0.2

Carbohydrate (g) 13.5

Fibre (g) 0.5

Ash (g) 0.3

Minerals

Calcium (mg) 18

Iron (mg) 0.3

Magnesium (mg) 12

Phosphorus (mg) 12

Potassium (mg) 98

Sodium (mg) 1

Vitamins

Ascorbic acid (mg) 10

Thiamin (mg) 0.09

Riboﬂ avin (mg) 0.04

Niacin (mg) 0.24

Vitamin A (IU) 53

Fig. 12.11. All parts of the pineapple fruit are used in different products (Rohrbach,

2003).

Pineapple 365

Bromelain, the proteolytic enzyme found in pineapple plants, particularly

in the stem, has a number of industrial and medicinal applications. Some

bromeliads, including pineapple, are grown for their leaf ﬁ bres, and many

more are grown as ornamentals.

FURTHER READING

Bartholomew, D.P. and Malézieux, E.P. (1994) Pineapple. In. Scha er, B. and Andersen,

P.C. (eds) Handbook of Environmental Physiology of Fruit Crops Vol. II. Subtropical and

Tropical Crops. CRC Press, Boca Raton, Florida, pp. 243–291.

Bartholomew, D.P., Malézieux, E., Sanewski, G.M. and Sinclair, E. (2003) Inﬂ orescence,

and fruit development and yield. In: Bartholomew, D.P., Paull, R.E. and Rohrbach,

K.G. (eds) The Pineapple: Botany, Production and Uses. CABI Publishing, Wallingford,

UK, pp. 167–202.

Hepton, A. (2003) Culture system. In: Bartholomew, D.P., Paull, R.E. and Rohrbach,

K.G. (eds) The Pineapple: Botany, Production and Uses. CABI Publishing, Wallingford,

UK, pp. 109–142.

Leal, F. and Coppens d’ Eeckenbrugge, G. (1996) Pineapple. In. Janick, J. and Moore,

J.N. (eds) Fruit Breeding, Vol. I: Tree and Tropical Fruits. John Wiley & Son, New York,

pp. 515–557.

Paull, R.E. and Chen, C.-C. (2003) Postharvest physiology, handling, and storage of

pineapple. In: Bartholomew, D.P., Paull, R.E. and Rohrbach, K.G. (eds). The Pineapple:

Botany, Production and Uses. CABI Publishing, Wallingford, UK, pp. 253–279.

Py, C., Lacoeuilhe, J.J. and Teisson, C. (1987) The Pineapple, Cultivation, and Uses. G.P.

Maisoneuve et Larose, Paris, France.

Rohrbach, K.G. and Johnson, M. (2003) Pests, diseases and weeds. In: Bartholomew,

D.P., Paull, R.E. and Rohrbach, K.G. (eds) The Pineapple: Botany, Production and Uses.

CABI Publishing, Wallingford, UK, pp. 203–251.

Soler, A. (1992) Pineapple – Quality Criteria. CIRAD-COLEACP, Montpellier, France.

366

REFERENCES

CHAPTER 1. INTRODUCTION

Codex Alimentarius (2001) Food Labelling Complete Texts. Joint FAO/WHO Food, Standards

Programme Codex Alimentarius Commission. FAO, Rome.

Crane, P.R. and Lidgard, S. (1989) Angiosperm diversiﬁ cation and paleolatitudinal

gradients in Cretaceous ﬂ oristic diversity. Science 246, 675–678.

FAO (2009) FAO Crop Production Statistics. FAO, Rome. http://faostat.fao.org/site/567/

default.aspx#ancor, accessed 17 November 2009.

avier, J.C., Ireland-Ripert, J., Laussucq, C., and Feinberg, M., CIQUAL – CNEVA (1993)

Table de composition des fruits exotiques, fruits de ceuillette d’Afrique. ORSTOM editions,

Lavoisier, INRA editions.

Meyer, N., Mittermeier, R.A., Mittermeier, C.G., da Fonseca, G.A.B. and Kent, J. (2000)

Biodiversity hotspots for conservation priorities. Nature 403, 853–858.

Nakasone, H.Y. and Paull, R.E. (1998) Tropical Fruits. CAB International, Wallingford,

UK.

Sabbe, S., Verbeke, W. and van Damme, P. (2009) Conﬁ rmation/disconﬁ rmation

of consumers’ expectations about fresh and processed tropical fruit products.

International Journal of Food Science & Technology 44, 539–551.

CHAPTER 2. THE TROPICS, ITS SOILS AND HORTICULTURE

Bluthgen, J. (1966) Allgemeine Klimageographie, 2nd edn. Walter de Gruyter, Berlin.

Cerri, C.E.P., Sparovek, G., Bernoux, M., Easterling, W.E., Melillo, J.M. and Cerri, C.C.

(2007) Tropical agriculture and global warming: impacts and mitigation options.

Scientia Agricola. 64, 83–99.

Easterling, W.E. and Apps, M. (2005) Assessing the consequences of climate change for

food and forest resources: a view from the IPCC. Climatic Change 70, 165–189.

Gates, D.M. (1966) Spectral distribution of solar radiation at the earth’s surface. Science

151, 523–529.

Gray, W.M. (1968) A global view of the origin of tropical disturbances and storms.

Monthly Weather Review 96, 669–700.

References 367

Ingram, J.S.I., Gregory, P.J. and Izac, A.M. (2008) The role of agronomic research in

climate change and food security policy. Agriculture, Ecosystems & Environment

126, 4–12.

Kalpage, F.S.C.P. (1976) Tropical Soils: Classiﬁ cation, Fertility and Management. Macmillan,

London.

Oliver, J.E. and Hidore, J.J. (1984) Climatology. Charles E. Merrill Publishing Company,

Columbus, Ohio.

Sanchez, P.A. (1976) Properties and Management of Soils in the Tropics. Wiley-Interscience

Publishers, New York.

Sanchez, P.A. and Buol, S.W. (1975) Soils of the tropics and the world food crisis. Science

188, 598–603.

Sanchez, P.A. and Salinas, J.G. (1981) Low input technology for managing oxisols and

ultisols in tropical America. Advances in Agronomy 34, 279–406.

Schultz, J. (2005) The Ecozones of the World: the Ecological Divisions of the Geosphere, 2nd

ed. Springer, Berlin.

Sutherst, R., Baker, R.H.A., Coakley, S.M., Harrington, R., Kriticos, D.J. and Scherm, H.

(2007) Pests under global change – meeting your future landlords? In: Candell, J.G.

(ed.) Terrestrial Ecosystems in a Changing World. Springer, New York, pp. 211–226.

Thornthwaite, C.W. (1948) An approach toward a rational classiﬁ cation of climate.

Geographic Review 38, 55–94.

Walter, H. (1973) Vegetation of the Earth. In Relation to Climate and Ecophysiological

Conditions, 2nd edn. Translated by Joy Weiser. Springer-Verlag, Berlin.

Watson, B.J. and Moncur, M. (1985) Criteria for Determining Survival: Commercial and

Best Minimum July Temperatures for Various Tropical Fruits in Australia. Wet Tropical

Regional Publication, Queensland, Australia.

CHAPTER 3. CULTIVATION

Avilán, L., Leal, F. and Bautista, D. (1989) Manual de Fruticultura. Editorial América,

Caracas, Venezuela (in Spanish).

Campbell, C.W. and Goldweber, S. (1985) Rare and Exotic Tropical Fruits: Trees and Plants.

Caloosa Rare Fruit Exchange, Ft. Myers, Florida.

Maxwell, L.S. and Maxwell, B.M. (1985) Florida Fruit. B.M. Maxwell Publisher, Florida.

Razeto, B. (1993) Para Entender la Fruticultura, 2nd edn. Vivarium, Santiago de Chile,

Chile (in Spanish).

Rice, E.L. (1974) Allelopathy. Academic Press, New York.

Wilkinson, K.M. and Elevitch, C.R. (2000) Multipurpose Windbreaks, Design and Species

for the Paciﬁ c Islands. Agroforestry Guides for Paciﬁ c Islands No. 8. Permanent

Agriculture Resources, Holualoa, Hawaii.

CHAPTER 4. TREE MANAGEMENT

Avilán, L., Leal, F. and Bautista, D. (1989) Manual de Fruticultura. Editorial América,

Caracas, Venezuela (in Spanish).

Baldini, E. (1992) Arboricultura General. Editorial Mundi-Prensa, Madrid (in Spanish).

368 References

Garner, R.J. and Chaudhri, S.A. (1976) The Propagation of Tropical Fruit Trees. Horticultural

Review No. 4. Commonwealth Bureau of Horticulture and Plantation Crops,

Commonwealth Agricultural Bureaux, Farnham Royal, Slough, UK.

Harris, R. (1983) Arboriculture: Care of Trees, Shrubs and Vines in the Landscape. Prentice-

Hall Inc., Englewood Cli s, New Jersey.

Jones, J.B., Wolf, B. and Mills, H.A. (1991) Plant Analysis Handbook. Micro-Macro

Publishing, Athens, Georgia.

McNeil, R.J. (2001) California Avocado Production. Horticulture and Crop Science

Department. Cal Poly State University, San Luis Obispo, California.

Penman, D., Close, R. and Jackson, D.I. (2003) Protección de los cultivos. In: Jackson,

D.I. and Looney, N.E. (eds) Producción de Frutas de Climas Templados y Subtropicales.

Ed. Acribia, S.A., Zaragoza, Spain (in Spanish).

Razeto, B. (1993) Para Entender la Fruticultura, 2nd edn. Vivarium, Santiago de Chile.

Chile (in Spanish).

Reuter, D.J. and Robinson, J.B. (eds) (1986) Plant Analysis: an Interpretative Manual.

Inkata Press, Melbourne, Australia.

Verheij, E.W.M. (1986) Towards a classiﬁ cation of tropical fruit trees. Acta Horticulturae

175, 137–150.

CHAPTER 5. POSTHARVEST TECHNOLOGY

Abbott, J.A. (1999) Quality measurement of fruits and vegetables. Postharvest Biology

and Technology 15, 201–206.

Ben-Yehoshua, S. (1987) Transpiration, water stress, and gas exchange. In: Weichmann,

J. (ed.) Postharvest Physiology of Vegetables. Marcel Dekker Inc. New York, pp.

113–170.

Brackett, R.E. (1999) Incidence, contributing factors, and control of bacterial pathogens

in produce. Postharvest Biology and Technology 15, 305–312.

Chen, N.M. and Paull, R.E. (1986) Development and prevention of chilling injury

in papaya fruit. Journal of the American Society for Horticultural Science 111,

639–643.

Cohen, E., Shalom, Y. and Rosenberger, I. (1990) Postharvest ethanol buildup and o -

ﬂ avour in ‘Murcott’ tangerine fruits. Journal of the American Society for Horticultural

Science 115, 775–778.

Cook, R. (1999) An overview of key food industry drivers: implications for fresh produce

industry. Journal of Food Distribution Research 30, 1–4.

Epperson, J.E. and Estes, E.A. (1999) Fruit and vegetable supply chain management,

innovations and competitiveness: Cooperative Regional Project S-222. Journal of

Food Distribution Research 30, 38–43.

Ga rey, J.J. (1978) Humidity: basic principles and measurement techniques. HortScience

13, 551–555.

Hewett, E.W. (2003) Perceptions of supply-chain management of perishable horticultural

crops: an introduction. Acta Horticulturae 604, 37–46.

Kader, A.A. (1993) Modiﬁ ed and controlled atmosphere storage of tropical fruits. In:

Champ, B.R., Highley, E. and Johnson, G.I. (eds) Postharvest Handling of Tropical

Fruits. ACIAR, Canberra, Australia, pp. 239–249.

References 369

LeBlanc, D.I., Stark, R., MacNeil, B., Goguen, B. and Beraulieu, C. (1996) Perishable food

temperature in retail stores. In: New Development in Refrigeration for Food Safety and

Quality. International Institute for Refrigeration Commission C2, 1996-6, 42–57.

O’Hare, T.J. (1993) Postharvest physiology and storage of carambola (starfruit): a

review. Postharvest Biology and Technology 2, 257–267.

O’Hare, T.J. (1995) Postharvest physiology and storage of rambutan. Postharvest Biology

and Technology 6, 189–199.

Paull, R.E. (1993) Tropical fruit physiology and storage potential. In: Champ, B.R.,

Highley, E. and Johnson, G.I. (eds) Postharvest Handling of Tropical Fruits. ACIAR,

Canberra, Australia, pp. 198–204.

Paull, R.E. (1994) Response of tropical commodities to insect disinfestation treatments.

HortScience 29, 16–24.

Paull, R.E. (1999) E ect of temperature and relative humidity on fresh commodity

quality. Postharvest Biology and Technology 15, 263–278.

Paull, R.E. and Armstrong, J. (1994) Introduction. In: Paull, R.E. and Armstrong, J.W.

(eds) Insect Pests and Fresh Horticultural Products: Treatments and Responses. CAB

International, Wallingford, UK, pp. 1–36.

Paull, R.E. and Chen, N.J. (2000) Heat treatments and fruit ripening. Postharvest Biology

and Technology 21, 21–37.

Paull, R.E., Nishijima, W., Reyes, M. and Cavaletto, C.G. (1997) Postharvest handling

and losses during marketing of papaya (Carica papaya L). Postharvest Biology and

Technology 11, 165–179.

Prussia, S.E. (2000) Soft systems methodologies for modeling postharvest chains. Acta

Horticulturae 536, 653–660.

Prussia, S.E., and Shewfelt, R.L. (1993) Systems approach to postharvest handling.

In: Shewfelt, R.L. and Prussia, S.E. (eds) Postharvest Handling. A Systems Approach.

Academic Press, New York, pp. 44–71.

Qi, S.C. (1982) The application of mechanical refrigeration to cave storage of fruit.

International Journal of Refrigeration 5, 235–237.

Robinson, J.E., Browne, K.M. and Burton, W.G. (1975) Storage characteristics of some

vegetables and soft fruits. Annals of Applied Biology 81, 399–408.

Sastry, S.K., Baird, C.D. and Bu ngton, D.E. (1978) Transpiration rates of certain fruits

and vegetables. ASHRAE Transactions 84, 237–255.

Shewfelt, R.L. (1999) What is quality? Postharvest Biology and Technology 15, 197–200.

Snowdon, A.L. (1990) A Color Atlas of Post-harvest Diseases and Disorders of Fruits and

Vegetables Vol 1: General Introduction and Fruits. CRC Press, Boca Raton, Florida.

Thompson, A.K. (1996) Postharvest Technology of Fruit and Vegetables. Blackwell Science

Ltd, Oxford.

Wills, R.B.H. and McGlasson, W.B. (1970) Loss of volatiles by apples in cool storage:

a di erential response to increased water loss. Journal of Horticultural Science 45,

283–286.

Yahia, E.M. (1998) Modiﬁ ed and controlled atmospheres for tropical crops. Horticultural

Reviews 22, 123–183.

Zagory, D. (1999) E ects of post-processing handling and packaging on microbial

populations. Postharvest Biology and Technology 15, 313–321.

370 References

CHAPTER 6. ANNONAS: CHERIMOYA, ATEMOYA AND

SWEETSOP

Alvarez-Garcia, L.A. (1949) Anthracnose of the Annonaceae in Puerto Rico. University

of Puerto Rico Journal of Agriculture 33, 27–43.

Campbell, C.W. (1985) Cultivation of fruits of the Annonaceae in Florida. Proceedings of

the American Society for Horticultural Science of the Tropical Region 29, 68–70.

Chen, C.C. and Paull, R. (2008) Annona squamosa, sweetsop. In: Janick, J. and Paull, R.

(eds) The Encyclopedia of Fruit and Nuts. CAB International, Wallingford, UK, pp.

48–53.

Cresswell, G. and Sanewski, G. (1991) Diagnosing nutrient disorders. In. Sanewski, G.

(ed.) Custard Apples – Cultivation and Crop Protection. Information Series QI90031,

Queensland Department of Primary Industry, Brisbane, Australia.

Dhingra, J., Mehrotra, R.S. and Aneja, I.R. (1980) A new postharvest disease of Annona

squamosa L. Current Science 49, 477–478.

Duarte, O. and Escobar, O. (1994) Mejora del cuajado de chirimoya (Annona cherimola

Mill.) cv. Cumbe, mediante polinización manual autógama y alógama. Proceedings

Interamerican Society for Tropical Horticulture 41, 162–165.

Duarte, O., Ramírez, A. and Franciosi, R. (1974a) Improving cherimoya fruit set with

plant regulators. Proceedings of the XIXth International Horticultural Congress.

Warsaw. IB, 459.

Duarte, O., Villagarcía, J. and Franciosi, R. (1974b) Efecto de algunos tratamientos en la

propagación de chirimoya (Annona cherimola Mill.) por semillas, estacas e injertos.

Proceedings of the Tropical Region of the American Society for Horticultural Science 18,

41–48 (in Spanish, English summary).

Duarte, O., Pineda, A. and Rodriguez, P.P. (1997) Mejora del cuajado en atemoya ‘Gefner’

(Annona cherimola × Annona squamosa) con diversos tratamientos de polinizacion

manual. Proceedings Interamerican Society for Tropical Horticulture 44, 92–94.

Ellstrand, N.C. and Lee, J.M. (1987) Cultivar identiﬁ cation of cherimoya (Annona

cherimola Mill.) using isozyme markers. Scientia Horticulturae 32, 25–31.

Franciosi, R. (1992) El Cultivo del Chirimoyo en el Perú. Ediciones FUNDEAGRO, Lima,

Peru (in Spanish).

Gardiazabal, F. and Rosenberg, G. (1993) El Cultivo del Chirimoyo. Ediciones Universitarias

de Valparaíso, Valparíso, Chile (in Spanish).

Gazit, S. and Eistenstein, D. (1985) Floral biology of Annona squamosa and Annona

cherimola in relation to spontaneous appearance of atemoya in Israel. Proceedings

of the Tropical Region of the American Society for Horticultural Science 29, 66–67.

George, A.P. and Nissen, R.J. (1986a) E ect of pruning and defoliation on precocity

of bearing of custard apple (Annona atemoya Hort.) var. African Pride. Acta

Horticulturae 175, 237–241.

George, A.P. and Nissen, R.J. (1986b) The e ects of root temperature on growth and dry

matter production of Annona species. Scientia Horticulturae

31, 95–99.

George, A.P. and Nissen, R.J. (1987a) E ects of cincturing, defoliation and summer

pruning of vegetative growth and ﬂ owering of custard apple (Annona cherimola

× Annona squamosa) in subtropical Queensland. Australian Journal of Experimental

Agriculture 27, 915–918.

George, A.P. and Nissen, R.J. (1987b) The e ects of day/night temperatures on growth

and dry matter production of custard apple. Scientia Horticulturae 31, 269–274.

References 371

George, A.P. and Nissen, R.J. (1988) The e ects of temperature, vapor pressure deﬁ cit and

soil moisture stress on growth, ﬂ owering and fruit set of custard apple (atemoya)

‘African Pride’. Scientia Horticulturae 34, 183–191.

George, A.P., Nissen, R.J. and Carseldine, M.L. (1989) E ect of season (vegetative

ﬂ ushing) and leaf position on the leaf nutrient composition of Annona spp. hybrid

cv. Pink’s Mammoth in south-eastern Queensland. Australian Journal of Experimental

Agriculture 29, 587–595.

Kshirsaga, S.V., Shinde, N.N., Rane, D.A. and Borikar, S.T. (1976) Studies on the ﬂ oral

biology in atemoya (Annona atemoya Hort.). South Indian Horticulture 24, 6–10.

Kumar, R., Hoda, M.N. and Singh, D.K. (1977) Studies on the ﬂ oral biology of custard

apple (Annona squamosa Linn). Indian Journal of Horticulture 34, 252–256.

Lo, S.S. (1987) Pruning technique, use of sprouting chemical and ﬂ ower initiation in

sugar apple (Annona squamosa). In: Chang. L.R. (ed.) Forcing Culture of Horticultural

Crops. Special Publication No. 10. Taichung District Agricultural Improvement

Station, Taichung, Taiwan (in Chinese, English summary), pp. 147–150.

Marler, J.E., George, A.P., Nissen, R.J. and Andersen, P.J. (1994) Miscellaneous

tropical fruits – annonas. In: Scha er. B.C. and Andersen, P.C. (eds) Handbook of

Environmental Physiology of Fruit Crops, Vol. II. Subtropical and Tropical Crops. CRC

Press, Boca Raton, Florida, pp. 200–206.

Pascual, L., Perfectti, F., Gutierres, M. and Vargas, A.M. (1993) Characterizing isozymes

of Spanish cherimoya cultivars. HortScience 28, 845–847.

Paull, R. (2008) Annona cherimola, cherimoya. In: Janick, J. and Paull, R. (eds) The

Encyclopedia of Fruit and Nuts. CAB International, Wallingford, UK, pp. 37–42.

Razeto, B. and Diaz de Valdes, E. (2001) E ect of summer pruning and bark girdling

on cherimoya (Annona cherimola Mill.) var. Concha Lisa. Agricultura Tecnica 6,

215–220.

Saavedra, E. (1979) Set and growth of Annona cherimola Mill. fruit obtained by hand-

pollination and chemical treatment. Journal of the American Society for Horticultural

Science 104, 668–673.

Samuel, R., Pineker, W., Balasubramaman, S. and Morawetz, W. (1991) Allozyme

diversity and systematics in Annonaceae – a pilot project. Plant System Evolution

178, 125–134.

Sanewski, G.M. (ed.) (1991) Custard Apples – Cultivation and Crop Protection. Information

Series QI90031, Queensland Department of Primary Industry, Brisbane,

Australia.

Smith, D. (1991) Insect pests. In: Sanewski, G. (ed.) Custard Apples – Cultivation and

Crop Protection

. Information Series QI90031, Queensland Department of Primary

Industry, Brisbane, Australia, pp. 73–79.

Thakur, D.R. and Singh, R.N. (1964) Studies on pollen morphology, pollination and fruit

set in some annonas. Indian Journal of Horticulture 22, 10–17.

Thakur, D.R. and Singh, R.N. (1965) Studies on ﬂ oral biology of Annonas. Indian Journal

of Horticulture 23, 238–252.

Wenkam, N.S. (1990) Foods of Hawaii and the Paciﬁ c Basin. Fruits and Fruit Products, Raw,

Processed, and Prepared, Vol. 4, Composition. Research Extension Series 110, HITAHR,

College of Tropical Agriculture and Human Resources, Honolulu, Hawaii.

Yang, C.S. (1987) Production of sugar-apple fruits in the winter. In: Chang, L.R. (ed.)

Forcing Culture of Horticultural Crops. Proceedings of a Symposium. Special Publication

No. 10, Taichung District Agricultural Improvement Station, Taichung, Taiwan,

pp. 129–140.

372 References

Yang, C.S. (1988) Application of plant growth regulators on Annona culture. In: Lin,

H.S., Chang, L.R. and Lin, J.H. (eds) The Application of Plant Growth Regulators on

Horticultural Crops. Symposium Proceedings. Special Publication No. 12, Taichung

District Agricultural Improvement Station, Changhua, Taiwan (Chinese, English

summary), pp. 305–320.

CHAPTER 7. AVOCADO

Ahmed, E.M. and Barmore, C.R. (1980) Avocado. In: Nagy, S. and Shaw, P.E. (eds) Tropical

and Subtropical Fruits. AVI Publishing, Westport, Connecticut, pp. 121–156.

Anon. (1995) International Standardisation of Fruits and Vegetables, Avocado. Organization

for Economic Cooperation and Development, Paris.

Arpaia, M.L., Bender, G.S. and Witney, G.W. (1992) Avocado clonal rootstock production

trial. In: Proceedings of the 2nd World Avocado Congress, Vol. I. University of California,

Riverside, California, pp. 305–310.

Ashworth, V.E.T.M. and Clegg, M.T. (2003) Microsatellite markers in avocado (Persea

americana Mill.): genealogical relationships among cultivated avocado genotypes.

Journal of Heredity 94, 407–415.

Barmore, C.R. (1976) Avocado fruit maturity. In: Sauls, J.W., Phillips, R.L. and Jackson,

L.K. (eds) The Avocado: Proceedings of the 1st International Tropical Fruit Short Course.

Fruit Crops Department, University of Florida, Gainesville, Florida, pp. 103–109.

Barrientos-Priego, A.F., Muñoz-Pérez, R., Borys, M.W. and Martinez-Damián, M.T.

(2000) Cultivares y portainjertos del aguacate. In: Téliz, D. (coord.). El aguacate y su

manejo integrado. Ediciones Mundi Prensa, México, Madrid, Barcelona.

Ben-Ya’acov, A. and Michelson, E. (1995) Avocado rootstocks. Horticulture Reviews 17,

381–429.

Ben-Ya’acov, A., Solís, A. and Peri, E. (1995) Progress in the study of avocado genetic

resources. II. The avocado genetic resources in Costa Rica. Programme and book

of abstracts of the 3rd World Avocado Congress. 22–27 October, Tel Aviv, Israel,

p. 109.

Bergh, B.O. (1969) Avocado. In: Ferweda, F.P. and Wit, F. (eds) Outline of Perennial

Crop Breeding in the Tropics. Landbouwhogeschool, Miscellaneous Paper No. 4,

Wageningen, The Netherlands, pp. 23–51.

Bergh, B.O. (1975) Avocados. In: Janick, J. and Moore, J.N. (eds) Advances in Fruit

Breeding. Purdue University Press, West Lafayette, Indiana, pp. 541–567.

Bergh, B.O. (1976) Avocado breeding and selection. In: Sauls, J.W., Phillips, R.L. and

Jackson, L.K. (eds) The Avocado. Proceedings of the 1st International Tropical Fruit

Short Course. Fruit Crops Department, University of Florida, Gainesville, Florida,

pp. 24–33.

Bergh, B. (1990a) The avocado and human nutrition, I. Some human health aspects of

the avocado. In: Proceedings of the 2nd World Avocado Congress, Vol. I. University of

California, Riverside, California, pp. 25–35.

Bergh, B. (1990b) The avocado and human nutrition, II. Avocado and your heart.

In: Proceedings of the 2nd World Avocado Congress, Vol. I. University of California,

Riverside, California, pp. 37–47.

Bergh, B. O. and Ellstrand, N.C. (1986) Taxonomy of the avocado. California Avocado

Society Yearbook 70, 135–145.

References 373

Bower, J.P. (1981a) Climatic Requirements of Avocado. B.l, Farming in South Africa,

Department of Agriculture and Water Supply, Pretoria, South Africa.

Bower, J.P. (1981b) Layout of an Avocado Orchard. D.3, Farming in South Africa,

Department of Agriculture and Water Supply, Pretoria, South Africa.

Bower, J.P. (1981c) Avocado Pollination and Pollinator Interplanting. G.4, Farming in

South Africa, Department of Agriculture and Water Supply, Pretoria, South Africa

(reprinted 1986).

Broadley, R.H. (ed.) (1991) Avocado Pests and Disorders. Information Series QI90013,

Queensland Department of Primary Industry, Brisbane, Australia.

Brokaw, W.H. (1975) Root rot resistant avocado clonal rootstocks. Plant Propagator

21(4), 7–8.

Campbell, C.W. and Malo, S.E. (1976) A survey of avocado cultivars. In: Sauls, J.W.,

Phillips, R.L. and Jackson, L.K. (eds) The Avocado. Proceedings of the 1st International

Tropical Fruit Short Course. Fruit Crops Department, University of Florida,

Gainesville, Florida, pp. 20–24.

Chaikiattiyos, S., Menzel, C.M. and Rasmussen, T.S. (1994) Floral induction in tropical

fruit trees, e ects of temperature and water supply. Journal of Horticultural Science

69, 397–415.

Chen, H., Morrell, P.L., Ashworth, V.E.T.M., de la Cruz, M. and Clegg, M.T. (2009) Tracing

the geographic origins of major avocado cultivars. Journal of Heredity 100, 56–65.

Co ey, M.D. (1987) Phytophthora root rot of avocado – an integrated approach to

control in California. Plant Disease 71, 1046–1052.

Crane, J.H., Scha er, B., Davenport, T.L. and Balerdi, C. (1992) Rejuvenation of a mature,

non-productive ‘Lula’ and ‘Booth 8’ avocado grove by topping and tree removal.

Proceedings of the Florida State Horticultural Society 105, 282–285.

Currier, W. (1992) New variety introduction under US conditions. In: Proceedings of the

2nd World Avocado Congress, Vol. II. University of California, Riverside, California,

pp. 609– 613.

Cutting, J.G.M., Cocker, B. and Wolstenholme, B.N. (1994) Time and type of pruning

cut a ect shoot growth in avocado (Persea americana (Mill.)). Journal of Horticultural

Science 69, 75–80.

Davenport, T.L., Parnitzki, P., Fricke, S. and Hughes, M.S. (1994) Evidence and

signiﬁ cance of self-pollination of avocado in Florida. Journal of the American Society

for Horticultural Science 119, 1200–1207.

de Villiers, A. and Ernst, A. (2007) Practical value of the Allesbeste microcloning

technique. Proceedings of the 6th World Avocado Congress, Viña del Mar, Chile.

Available at http://www.avocadosource.com/WAC6/en/Extenso/1a-5.pdf

(accessed 22 May 2010).

Diaz-Avelar, J. (1979) The Cultivation of Avocado. XXV Anniversary, FIRA, Banco de

Mexico (in Spanish).

Duarte, O., Balvin, A. and Franciosi, R. (1975) Efecto de diversos tratamientos con

ácido giberélico sobre el crecimiento de plántulas de palto (Persea americana Mill)

en vivero. Proceedings of the Tropical Region, American Society for Horticultural Science

19, 45–55.

Finazzo, S.A., Davenport, T.L. and Scha er. B. (1994) Partitioning of photoassimilates

in avocado (Persea americana Mill.) during ﬂ owering and fruit set. Tree Physiology

14, 153–164.

Furnier, G.P., Cummings, P.M. and Clegg, M.T. (1990) Evolution of the avocado as

revealed by DNA restriction fragment variation. Journal of Heredity 81, 183–188.

374 References

Gabor, B.K., Guillemet, F.B. and Co ey, M.D. (1990) Comparison of ﬁ eld resistance to

Phytophthora cinnamoni in twelve avocado rootstocks. HortScience 25, 1655–1656.

Garcia, V.A. (1975) Cytogenetic studies in the genus Persea (Lauraceae). I. Karyology of

seven species. Canadian Journal of Genetic Cytology 17, 170–180.

Garcia, VA. and Tsunewaki, K. (1977) Cytogenetical studies in the genus Persea

(Lauraceae). III. Electrophoretical studies on peroxidase isoenzymes. Japanese Journal

of Genetics 52, 379–386.

Gazit, S. (1976) Pollination and fruit set of avocado. In: Sauls, J.W., Phillips, R.L. and

Jackson, L.K. (eds) The Avocado. Proceedings of the 1st International Tropical Fruit

Short Course. Fruit Crops Department, University of Florida, Gainesville, Florida,

pp. 88–92.

Gomez, R.E., Soule, J. and Malo, S.E. (1973) Anatomical aspects of avocado stems with

reference to rooting. Proceedings of the American Society for Horticultural Science of

Tropical Region 17, 23–28.

Gustafson, D. (1976) Avocado water relations. In: Sauls, J.W., Phillips, R.L. and Jackson,

L.K. (eds) The Avocado. Proceedings of the 1st International Tropical Fruit Short Course.

Fruit Crops Department, University of Florida, Gainesville, Florida, pp. 47–53.

Hatton, T.T. Jr and Campbell, C.W. (1959) Evaluation indices for Florida avocado

maturity. Proceedings of the Florida State Horticultural Society 72, 349–353.

Hatton, T.T. and Reeder, W.F. (1972) Relationship of bloom date to the size and oil

content of ‘Booth 8’ avocados. Citrus Industry 53, 20–21.

Kadman, A. and Ben-Ya’acov, A. (1970a) Avocado, selection of rootstocks and other

work related to salinlty and time. In: 1960–1969 Report. Division of Subtropical

Horticulture, Volcani Institute of Agricultural Research, Bet Dagan, Israel, pp.

23–39.

Kadman, A. and Ben-Ya’acov, A. (1970b) Vegetative propagation, A. Rooting of leaf-

bearing cuttings. In: 1960–1969 Report. Division of Subtropical Horticulture,

Volcani Institute of Agricultural Research, Bet Dagan, Israel, pp. 47–50.

Kaiser, C. and Wolstenholme, B.N. (1994) Aspects of delayed harvest of ‘Hass’

avocado (Persea americana Mill.) fruit in a cool subtropical climate. II. Fruit size,

yield, phenology and whole tree starch cycling. Journal of Horticultural Science 69,

447–457.

Kawano, Y., Hylin, J.W. and Hamilton, R.A. (1976) Plant Products of Economic Potential in

Hawaii. III. Quantity and Quality of Oil Obtained from Hawaii-grown Avocado Varieties.

Research Report 211, Hawaii Agricultural Experimental Station, Honolulu,

Hawaii.

Knight. R.J. Jr (1976) Breeding avocados for cold hardiness. In: Sauls, J.W., Phillips, R.L.

and Jackson, L.K. (eds) The Avocado. Proceedings of the 1st International Tropical Fruit

Short Course. Fruit Crops Department, University of Florida, Gainesville, Florida,

pp. 33–36.

Kremer-Köhne, S. and Köhne, J.S. (2007) 25 years of avocado rootstock development

in South Africa. Proceedings of the 6th World Avocado Congress

, Viña del Mar,

Chile. Available at http://www.avocadosource.com/WAC6/en/Extenso/1a-8.pdf

(accessed 22 May 2010).

Lavi, U., Lahav, E., Cenizi. A., Degani, D., Gazit, S. and Hillel, J. (1991) Quantitative

genetic analysis of traits in avocado cultivars. Plant Breeding 106, 149–160.

Lavi, U., Lahav, E., Degani, C. and Gazit, S. (1992) The genetics of the juvenile phase

in avocado and its application for breeding. Journal of the American Society for

Horticultural Science 117, 981–984.

References 375

Lavi, U., Lahav, E., Degani, C. and Gazit, S. (1993a) Genetics of skin color, ﬂ owering

group and anise scent in avocado. Journal of Heredity 84, 82–84.

Lavi, U., Lahav, E., Degani, C., Gazit, S. and Hillel, J. (1993b) Genetic variance components

and heritabilities of several avocado traits. Journal of the American Society for

Horticultural Science 118, 400–404.

Malo, S.E. (1976) Mineral nutrition of avocados. In: Sauls, J.W., Phillips, R.L. and

Jackson, L.K. (eds) The Avocado. Proceedings of the 1st International Tropical Fruit

Short Course. Fruit Crops Department, University of Florida, Gainesville, Florida,

pp. 42–46.

McKellar, M.A., Buchanan, D.W., Ingram, D.L. and Campbell, C.W. (1992) Freezing

tolerance of avocado leaves. HortScience 27, 341–343.

McMillan, R.T. Jr (1976) Diseases of avocado. In: Sauls, J.W., Phillips, R.L. and Jackson,

L.K. (eds) The Avocado. Proceedings of the 1st International Tropical Fruit Short Course.

Fruit Crops Department, University of Florida, Gainesville, Florida, pp. 66–70.

Miller, C.D., Bazore, K. and Bartow, M. (1965) Fruits of Hawaii. Description. Nutritive

Value, and Recipes. University of Hawaii Press, Honolulu, Hawaii.

Mora, A., Teliz, D., Mora, G. and Etchevers, J. (2000) Enfermedades de la raíz. In: Téliz, D.

(coord). El aguacate y su manejo integrado. Ediciones Mundi Prensa, México, Madrid,

Barcelona.

Nishimoto, R.K. and Yee, W.Y.J. (1980) A Guide to Chemical Weed Control in Tropical and

Subtropical Fruit and Nut Crops in Hawaii. CES Circular 423 (revised), University of

Hawaii, Honolulu, Hawaii.

Ploetz, R.C., Ramos, J.L., Parrado, J.L. and Shepard, E.S. (1991) Shoot and root growth

cycles of avocado in south Florida. Proceedings of the Florida State Horticulture

Society 104, 21–24.

Popenoe, W. (1920) Manual of Tropical and Subtropical Fruits. Macmillan, NewYork.

Rainey, C.A., Gilette, G., Brydon, A., McIntyre, S., Rivers, O., Vasquez, C.A. and Wilson,

E. (1992) Physiological maturity and percent dry matter of California avocado.

In: Proceedings of the 2nd World Avocado Congress, Vol. II. University of California,

Riverside, California, pp. 379–385.

Rainey, C., A ick, M., Bretschger, K. and Alﬁ n-Slater, R.B. (1994) The California

avocado. Nutrition Today 29(3), 23–27.

Salazar-García, S. (2000) Fisiología reproductiva del aguacate: In Téliz, D. (coord.).

El aguacate y su manejo integrado. Ediciones Mundi Prensa, México, Madrid,

Barcelona.

Scha er, B., Pena, J., Lara, S.P. and Buisson, D. (1986) Net photosynthesis, transpiration,

and stomatal conductance of avocado leaves infested by avocado red mites.

Proceedings of the Interamerican Society for Tropical Horticulture 30, 73–82.

Scora, R.W. and Bergh, B.O. (1992) Origin of and taxonamic relationship within the

genus Persea. In: Proceedings of the 2nd World Avocado Congress, Vol. II. University of

California, Riverside, California, pp. 505–514.

Sedgley, M. and Grant, W.J.R. (1983) E ecct of low temperature during ﬂ owering on

ﬂ oral cycle and pollen tube growth in nine avocado cultivars. Scientia Horticulturae

18, 207–213.

Sedgley, M., Scholeﬁ eld, P.B. and Alexander, McE.D. (1985) Inhibition of ﬂ owering

of Mexican- and Guatemalan-type avocados under tropical conditions. Scientia

Horticulturae 25, 21–30.

Valmayor, R.V. (1967) Cellular development of the avocado from blossom to maturity.

Philippine Agriculturalist 50, 907–976.

376 References

Violi, H.A., Brown, J.S., Tondo C.L., Borrone, J.W. and Schnell, R.J. (2009) Microsatellite

markers reveal low breeding system e cacy and pollen contamination can limit

production of full-sib avocado progeny. Scientia Horticulturae 120, 360–366.

Wenkam, N.S. (1990) Foods of Hawaii and the Paciﬁ c Basin. Fruits and Fruit Products: Raw,

Processed, and Prepared, Vol. 4, Composition. Research Extension Series 110, College

of Tropical Agriculture and Human Resources, University of Hawaii, Honolulu,

Hawaii.

Whiley, A.W. (1984) Lauraceae. In: Page, P.E. (compiler) Tropical Tree Fruit for Australia.

Information Series Q183018, Queensland Department of Primary Industry,

Brisbane, Australia, pp. 70–77.

Whiley, A.W., Saranah, J.B., Cull, B.W. and Pegg, K.G. (1988a) Manage avocado tree

growth cycles for productivity gains. Queensland Agriculture Journal 114, 29–36.

Whiley, A.W., Chapman, K.R. and Saranah, J.B. (1988b) Water loss by ﬂ oral structures

of avocado (Persea americana cv. Fuerte) during ﬂ owering. Australian Journal of

Agricultural Research 39, 457–467.

Whiley, A.W., Saranah, J.B. and Rasmussen, T.S. (1992) E ect of time of harvest on fruit

size, yield and trunk starch concentrations of ‘Fuerte’ avocado. Proceedings of the

2nd World Avocado Congress, Vol. I. University of California, Riverside, California,

pp. 155–159.

Whiley, A.W., Hargreaves, P.A., Pegg, K.G., Doogan, V.J., Ruddle, L.J., Saranah, J.B.

and Langdon, P.W. (1995) Changing sink strengths inﬂ uence translocation of

phosphorate in avocado (Persea americana Mill.) tree. Australian Journal of Agricultural

Research 46, 1079–1090.

Williams, L.O. (1976) The botany of the avocado and its relatives. In: Sauls, J.W., Phillips,

R.L. and Jackson, L.K. (eds) The Avocado. Proceedings of the 1st International Tropical

Fruit Crop Short Course. Fruit Crops Department, University of Florida, Gainesville,

Florida, pp. 9–15.

Wolstenholme, B.N. and Whiley, A.W. (1992) Requirements for improved fruiting

e ciency in the avocado tree. Proceedings of the 2nd World Avocado Congress, Vol. I.

University of California, Riverside, California, pp. 161–167.

Yee, W. (1978) Producing Avocado in Hawaii. CES Circular 382 (revised), University of

Hawaii, Honolulu, Hawaii.

Zentmyer, G.A. (1976) Soil-borne pathogens of avocado. In: Sauls, J.W, Phillips, R.L. and

Jackson, L.K. (eds) The Avocado. Proceedings of the 1st International Tropical Fruit Crop

Short Course. Fruit Crops Department, University of Florida, Gainesville, Florida,

pp. 75–82.

CHAPTER 8. BANANA AND PLANTAIN

Acedo, A.L. and Bautista, O.K. (1991) Enhancing ripening of ‘Saba’ banana (Musa, BBB

group) fruits with Gliricidia leaves as ethylene source. Philippine Agriculturalist 71,

351–365.

Baldry, J., Coursey, D.G. and Howard, G.E. (1981) The comparative consumer acceptability

of triploid and tetraploid banana fruit. Tropical Science 23, 33–66.

Belalcazar, S.W. (1991) El cultivo del plátano (Musa AAB Simmonds) en el Trópico. Manual

de Asistencia Técnica No. 50. Instituto Colombiano Agropecuario, Centro Nacional

References 377

de Investigaciones para el Desarrollo (Canadá), Comité Departamental de Cafeteros

de Quindío, Red Internacional para el Mejoramiento del Plátano y Banano. Cali,

Colombia.

Daniells, J.W. and O’Farrell, P.J. (1987) E ect of cutting height of the parent pseudostem

on yield and time of production of the following sucker in banana. Scientia

Horticulturae 31, 89–94.

Duarte, O. (1991) Manual del Cultivo del Banano. Escuela Agrìcola Panamericana – El

Zamorano, Honduras.

Espino, R.R.C., Jamalualdin, S.H., Silayoi, B. and Nasution, R.E. (1992) Musa L. (edible

cultivars). In: Verheij, E.W.M. and Coronel, R.E. (eds) Plant Resources in South East

Asia, No. 2, Edible Fruits and Nuts. Prosea, Bogor, Indonesia.

Galán Saúco, V. (1992) Los Frutales Tropicales en los Subtropicos. II Plátano (banano).

Mundi Prensa, Madrid (in Spanish).

Gowen, S. (ed.) (1995) Bananas and Plantains. Chapman and Hall, London.

Israeli, Y. and Lahav, E. (1986) Banana. In: Monselise, S.P. (ed.) CRC Handbook of Fruit

Set and Development. CRC Press, Boca Raton, Florida, pp. 45–73.

Lahav, E. and Turner, D.W. (1983) Fertilizing for High Yield Banana. Bulletin No. 7,

International Potash Institute, Bern, Switzerland.

Lardizabal, R. and Gutiérrez, H. (2006) Producción de plátano de alta densidad. Programa

de Diversiﬁ cación Económica Rural (USAID-RED) Oﬁ cinas de FHIA, La Lima,

Honduras.

Lebot, V., Aradhya, K.M., Manshardt, R. and Meilleur, B. (1993) Genetic relationships

among cultivated bananas and plantains from Asia and the Paciﬁ c. Euphytica 67,

163–175.

Lodh, S.B., Ravel, P., Selvaraj, V. and Kohli, R.R. (1971) Biochemical changes with

growth and development of Dwarf Cavendish banana. Indian Journal of Horticulture

28, 38–45.

Loyola Santos, J.L., Shephard, K. and Alves, E.J. (1986) Propagacao rápida da bananeira.

Informe Agropecuario Belo Horizonte 12(133), 33–38.

Marriot, J., Robinson, M. and Karikari, S. (1981) Starch and sugar transformation during

the ripening of plantains and bananas. Journal of Science of Food and Agriculture 32,

1021–1026.

Martín-Prevel, P. (1990) Past, present, and future of tropical fruit nutrition with special

reference to banana. Acta Horticulturae 275, 523–534.

Murray, D.B. (1961) Shade and fertilizer relations in the banana. Tropical Agriculture 38,

123–132.

Novak, F.J. (1992) Musa (banana and plantains). In: Hammerschlag, F.A. and Litz, R.E.

(eds) Biotechnology of Perennial Fruit Crops. CAB International, Wallingford, UK, pp.

449–488.

Ortiz, R. (2008) Musaceae, Musa spp. (banana and plantain). In: Janick, J. and Paull, R.

E. (eds) The Encyclopedia of Fruits and Nuts. CAB International, Wallingford, UK, pp.

513–522.

Reynolds, P.K. (1951) Earliest evidence of banana culture. Journal of American Oriental

Society 71(4) (Suppl.).

Risède, J.M., Chabrier, C., Dorel, M., Dambas, T., Achard, R. and Quénerhevé, P. (2010)

Integrated management of banana nematodes: lessons from a case study in the

French West Indies. Banana Case Study, Guide Number 4, Banana Cropping System

Research Unit, CIRAD, France.

378 References

Robinson, J.C. and Human, N.B. (1988) Forecasting of banana harvest (‘Williams’)

in the subtropics using seasonal variation in bunch development rate and bunch

mass. Scientia Horticulturae 34, 249–263.

Robinson, J.C. and Nel, D.J. (1985) Comparative morphology, phenology and production

potential of banana cultivars ‘Dwarf Cavendish’ and ‘Williams’ in the Eastern

Transvaal Lowveld. Scientia Horticulturae 25, 149–161.

Robinson, J.C. and Nel, D.J. (1990) Competitive inhibition of yield potential in a

‘Williams’ banana plantation due to excessive sucker growth. Scientia Horticulturae

43, 225–236.

Rowe, P. and Rosales, F.E. (1996) Bananas and plantains. In: Janick, J. and Moore, J.N.

(eds) Fruit Breeding, Vol. I, Tree and Tropical Fruits. John Wiley & Sons, New York, pp.

167–211.

Simmonds, N.W. (1982) Bananas, 2nd edn. Tropical Agricultural Series, Longman,

London.

Smith, M.K. (1988) A review of factors inﬂ uencing the genetic stability of

micropropagated bananas. Fruits 43, 219–223.

Stover, R.H. and Simmonds, N.W. (1987) Bananas. Longman, London.

Turner, D.W. (1970) Daily variation in banana leaf growth. Australian Journal of

Experimental Agriculture and Animal Husbandry 10, 231–234.

Turner, D.W. (1994) Bananas and plantains. In: Scha er, B. and Andersen, P.C. (eds)

Handbook of Environmental Physiology of Fruit Crops. Vol. II, Subtropical and Tropical

Crops. CRC Press, Boca Raton, Florida, pp. 37–64.

Vuylsteke, D., Ortiz, R., Pasberg-Gauhl, C., Gauhl, F., Gold, C., Ferris, S. and Speizer, P.

(1993) Plantain and banana research at the International Institute of Tropical

Agriculture. HortScience 28, 873–874, 970–971.

Wainwright, H. (1992) Improving the utilization of cooking bananas and plantains.

Outlook on Agriculture 21, 177–181.

Wenkam, N.S. (1990) Foods of Hawaii and the Paciﬁ c Basin, Fruits and Fruit Products, Raw,

Processed, and Prepared, Vol. 4, Composition. Research Extension Series 110, College

of Tropical Agriculture and Human Resources, University of Hawaii, Honolulu,

Hawaii.

Wong, S., Kiew, R., Argent, G., Set, O., Lee, S.K. and Gan, Y.Y. (2002) Assessment of

the validity of the Sections in Musa (Musaceae) using ALFP. Annals of Botany 90,

231–238.

CHAPTER 9. LITCHI AND LONGAN

Litchi

Alexander, D.McE., Scholeﬁ eld, P.B. and Frodsham, A. (1982) Litchi. In. Some Tree

Fruits for Tropical Australia. Commonwealth Scientiﬁ c and Industrial Research

Organization, Canberra, Australia, p. 31.

Anonymous (1985) An Album of Guangdong Litchi Varieties in Full Color. Guangdong

Province Scientiﬁ c Technology Commission. Guangdong, China.

Aradhya, M.K., Zee, F.T. and Manshardt, R.M. (1995) Isozyme variation in lychee (Litchi

chinensis Sonn.). Scientia Horticulturae 63, 21–25.

References 379

Campbell, C.W. and Knight, R.J. Jr (1987) Production of litchis. In: Cultivation and

Production of Tropical Fruits. 23rd Congress, NORCOFEL, September 1983, Canary

Islands (in Spanish), pp. 215–221.

Chapman, K.R. (1984) Sapindaceae. In: Page, P.E. (compiler) Tropical Tree Fruits for

Australia. Information Series Q183018, Queensland Department of Primary

Industry, Brisbane, Australia. Chapter 26, pp.179–191.

Chen, W.S. and Ku, M.L. (1988) Ethephon and kinetin reduce shoot length and increase

ﬂ ower bud formation in lychee. HortScience 23, 1078.

Galán Saúco, V. (1989) Litchi Cultivation (Menini, U.G. FAO Coordinator). FAO Plant

Production and Plant Protection Paper No. 83. FAO, Rome (in Spanish).

Galán Saúco, V. (1990) Los frutales tropicales en las subtropicos. I. Aquacate, mango, litchi,

longan. Mundiprensa, Madrid (in Spanish).

Gro , G.W. (1921) The Lychee and Lungan. Orange Judd Co., New York.

Hieke, S., Menzel, C.M., Doogan, V.J. and Ludders, P. (2002) The relationship between

yield and assimilate supply in lychee (Litchi chinensis Sonn.). Journal of Horticultural

Science and Biotechnology 77, 326–332.

Huang, H.B. and Qiu, Y.X. (1987) Growth correlations and assimilate partitioning

in arillate fruit of Litchi chinensis Sonn. Australian Journal of Plant Physiology 14,

181–186.

Huang, H.B., Jiang, S.Y. and Xie, C. (1983) The initiation of aril and ontogeny of fruit in

Litchi chinensis Sonn. Journal of the South China Agriculture College 4, 78–83.

Joubert, A.J. (1986) Litchi. In: Monselise, S.P. (ed.) CRC Handbook of Fruit Set and

Development. CRC Press, Inc., Boca Raton, Florida, pp.233–246.

Kadman, A. and Gazit, S. (1970) Flowering and Fruiting of Litchi. Division of Subtropical

Horticulture, Volcani Institute of Agricultural Research, Bet Dagan, Israel,

pp.120–122.

Khan, I., Misra, R.S. and Srivastava, R.P. (1976) E ects of plant growth regulators on the

fruit drop, size and quality of litchi cultivar Rose Scented. Progressive Horticulture 8,

61–69.

Limangkura, L. (1966) Studies on the nature of ovule abortion in the Gro variety of

lychee (Litchi chinensis Sonn.). MS thesis, Department of Horticulture, University of

Hawaii, Honolulu, Hawaii.

Lin, T.S., Shau, S.M., Yen, C.R., Lin, T.C. and Chang, J.W. (1991) E ects of fruits, leaves,

light intensity and pruning on ﬂ owering of litchi (Litchi chinensis Sonn.). Second

Symposium on Forcing Culture of Horticultural Crops. Taichung District Agricultural

Improvement Station, Taiwan, Special Publication No. 23 (Chinese, English

summary), pp.127–136.

Menzel, C.M. (1983) The control of ﬂ oral initiation in lychee: a review. Scientia

Horticulturae 21, 201–215.

Menzel, C.M. (1985) Propagation of lychee: a review. Scientia Horticulturae 25, 31–48.

Menzel, C.M. and Paxton, B.F. (1986a) A screening technique for lychee genotypes

adapted to warm climates. Acta Horticulturae 175, 59–61.

Menzel, C.M. and Paxton, B.F. (1986b) The e ect of cincturing on ﬂ owering of lychee in

subtropical Queensland. Acta Horticulturae 175, 233–235.

Menzel, C.M. and Simpson, D.R. (1987) E ect of cincturing on growth and ﬂ owering

of lychee over several seasons in subtropical Queensland. Australian Journal of

Experimental Agriculture 27, 733–738.

Menzel, C.M. and Simpson, D.R. (1988) E ect of temperature on growth and ﬂ owering of

litchi (Litchi chinensis Sonn.) cultivars. Journal of Horticulture Science 63, 349–360.

380 References

Menzel C.M. and Simpson, D.R. (1990) Performance and improvement of lychee

cultivars: a review. Fruit Varieties Journal 44, 197–215.

Menzel, C.M. and Simpson, D.R. (1991) A description of lychee cultivars. Fruit Varieties

Journal 45, 45–56.

Menzel, C.M. and Simpson, D.R. (1994) Lychee. In: Scha er, B. and Andersen, P.C. (eds)

Handbook of Environmental Physiology of Fruit Crops Vol II. Subtropical and Tropical

Crops. CRC Press, Boca Raton, Florida, pp. 123–144.

Menzel, C.M., Watson, B.J. and Simpson, D.R. (1988) The lychee in Australia. Queensland

Agriculture Journal 114, 19–27.

Menzel, C.M., Rasmussen, T.S. and Simpson, D.R. (1989) E ect of temperature and leaf

water stress on growth and ﬂ owering of litchi (Litchi chinensis Sonn.). Journal of

Horticultural Science 64, 739–752.

Mo, B.C. (ed.) (1992) Litchi High Production Cultivation and Technology. Guangxi Science

and Technology Publishers, Nanning, China ( in Chinese).

Morton, J.F. (1987) Fruits of Warm Climates. Morton, Miami, Florida.

Mustard, M.J. (1954) Fundamentals of panicle di erentiation. Proceedings of the Florida

Lychee Growers’ Association 1, 7–8.

Nakasone, H.Y. and Paull, R.E (1998) Tropical Fruits. CAB International, Wallingford,

UK.

Nakata, S. (1953) Girdling as a Means of Inducing Flower Bud Initiation in Litchi. Progress

Note 95, University of Hawaii, Hawaii Agriculture Experiment Station, Honolulu,

Hawaii.

Nakata, S. and Suehisa, R. (1969) Growth and development of Litchi chinensis as a ected

by soil-moisture stress. American Journal of Botany 56, 1121–1126.

Nakata, S. and Watanabe, Y. (1966) E ects of photoperiod and night temperature on the

ﬂ owering of Litchi chinensis. Botanical Gazette 127, 146–152.

Pandey, R.S. and Yadava, R.P.S. (1970) Pollination of litchi (Litchi chinensis Sonn.)

by insects with special reference to honey bees. Journal of Apiculture Research 9,

103–105.

Paull, R.E. and Chen, N.J. (1987) E ect of storage temperature and wrapping on quality

characteristics of litchi fruit. Scientia Horticulturae 33, 223–236.

Paull, R.E., Chen, N.J., Deputy, J., Huang, H.B., Cheng, G.W. and Gao, F.F. (1984) Litchi

growth and compositional changes during fruit development. Journal of the

American Society for Horticultural Science 109, 817–821.

Paull, R.E., Reyes, M.E.Q. and Reyes, M.U. (1995) Litchi and rambutan insect

disinfestation: treatments to minimize induced pericarp browning. Postharvest

Biology and Technology 6, 139–148.

Prasad, A. and Jauhari, C.S. (1963) E ect of 2,4,5-T and alpha NAA on ‘drop stop’ and

size of litchi fruits. Madras Agricultural Journal 50, 28–29.

Singh, L.B. and Singh, U.P. (1954) The Litchi (Litchi chinensis Sonn.). Superintendent of

Printing and Stationery, Lucknow, India.

Singh, U.S. and Lal, R.K. (1980) Inﬂ uence of growth regulators on setting, retention

and weights of fruit in two cultivars of litchi. Scientia Horticulturae 12, 321–326.

Storey, W.B. (1973)

The Lychee. California Avocado Society Yearbook 1972–1973,

pp.75–86.

Storey, W.B., Hamilton, R.A. and Nakasone, H.Y. (1953) Gro – a New Variety of

Lychee. Circular 39, University of Hawaii, Hawaii Agriculture Experiment Station,

Honolulu, Hawaii.

References 381

Viruel, M.A. and Hormaza, J.I. (2004) Development, characterization and variability

analysis of microsatellites in lychee (Litchi chinensis Sonn., Sapindaceae). TAG

Theoretical and Applied Genetics 108, 896–902.

Wenkam, N.S. (1990) Foods of Hawaii and the Paciﬁ c Basin. Fruits and Fruit Products: Raw,

Processed and Prepared. Vol. 4. Composition. Research Extension Series 110, College

of Tropical Agriculture and Human Resources, Honolulu, Hawaii.

Wills, R.B.H., Lim, J.S.K. and Greenﬁ eld, H. (1986) Composition of Australian foods. 31.

Tropical and subtropical fruit. Food Technology Australia 38, 118–123.

Yen, C.R. (1995) Litchi. In: Taiwan Agricultural Encyclopedia Crops, 2nd edn. Agricultural

Publisher Council, Taipei, Taiwan (in Chinese), pp. 33–42.

Yuan, R.C. and Huang, H.B. (1988) Litchi fruit abscission: its patterns, e ect of shading,

and relation to endogenous abscisic acid. Scientia Horticulturae 36, 281–292.

Longan

Chapman, K.R. (1984) Sapindaceae. In: Page, P.E. (compiler) Tropical Tree Fruits for

Australia. Information Series Q183018, Queensland Department of Primary

Industry, Brisbane, Australia, Chapter 26, pp.179–191.

Chian, G.Z., Hee, Y.Q., Lin, Z.Y., Liu, M.Y. and Feng, X.B. (1996) Longan High Production

Cultivation Techniques. Guangxi Science Technology Publishers. Nanning, China (in

Chinese).

Galán Saúco, V. (1990) Los frutales tropicales en las subtropicos. I. Aquacate, mango, litchi,

longan. Mundiprensa, Madrid (in Spanish).

Gro , G.W. (1921) The Lychee and Lungan. Orange Judd Co., New York.

Ke, G.W. (1990) Development of ﬂ esh and seed of longan. Symposium on Litchi and

Longan. Guangxi Subtropical Fruit Research and Development O ce, Nanning,

China, pp. 176–178.

Lian, T.K. and Chen, L.L. (1965) A preliminary observation on the ﬂ ower bud initiation

of longan in Foochow. Acta Horticulture Sinica 4, 13–18.

Liu, X.H. and Ma, C.L. (2001) Production and research of longan in China. Acta

Horticulturae 558, 73–82.

Matsumoto, T.K., Nagao, M.A. and Mackey, B. (2007) O -season ﬂ ower induction

of longan with potassium chlorate, sodium chlorite and sodium hypochlorite.

HortTechnology 17, 296–300.

Menzel, C.M., Watson, B.J. and Simpson, D.R. (1988b) Longans – a place in Queensland’s

horticulture? Queensland Agriculture Journal 115, 251–265.

Nakasone, H.Y. and Paull, R.E. (1998) Tropical Fruits. CAB International, Wallingford,

UK.

Subhadrabandhu, S. and Yapwattanaphun, C. (2001) Regulation o -season ﬂ owering

of longan in Thailand. Acta Horticulturae 558, 193–198.

Wenkam, N.S. (1990) Foods of Hawaii and the Paciﬁ c Basin. Fruits and Fruit Products: Raw,

Processed and Prepared. Vol. 4. Composition. Research Extension Series 110, College

of Tropical Agriculture and Human Resources, Honolulu, Hawaii.

Wills, R.B.H., Lim, J.S.K. and Greenﬁ eld, H. (1986) Composition of Australian foods. 31.

Tropical and subtropical fruit. Food Technology Australia 38, 118–123.

Yen, C.R. and Chang, J.W. (1991) Variation of fruit characters among longan varieties

in Taiwan. Journal of the Chinese Society for Horticultural Science 37, 21–34.

382 References

Yen, C.R., Chau, C.N., Chang, J.W. and Tzeng, J.C. (2001) E ects of chemicals on ﬂ owering

in longan. Journal of the Chinese Society for Horticultural Science 47, 195–200.

Yen, C.R., Tzeng, J.C., Chau, C.N. and Chang, J.W. (2005) Longan production in Taiwan.

Acta Horticulturae 665, 61–66.

Zee, F., Chan, H.T. Jr and Yen, C.R. 1998. Lychee, longan, rambutan and pulasan. In:

Shaw, P.E., Chan, H.T. Jr and Nagy, S. (eds) Tropical and Subtropical Fruits. AgScience,

Inc. Auburndale, Florida, pp. 290–335.

CHAPTER 10. MANGO

Adlan, H.A. (1965) Floral morphology as related to the fruit drop in mango (Mangifera

indica L.). MSc thesis, Department of Horticulture, University of Hawaii. Honolulu,

Hawaii.

Akamine, E.K. (1976) Problems in shipping fresh Hawaiian tropical and subtropical

fruits. Acta Horticulturae 57, 157–161.

Azzouz, S., Said, G.A. and Abdella, M.Y. (1989) Studies on the control of malformation

in some mango cultivars. Zagazig Journal of Agricultural Research 16, 43–47.

Bondad, N.D. and Apostol, C.J. (1979) Induction of ﬂ owering and fruiting in immature

mango shoots with KNO

. Current Science 48, 591–593.

Campbell, C.W. (1961) Comparison of yields of polyembryonic and monoembryonic

mangos. Proceedings of the Florida State Horticultural Society 74, 363–365.

Campbell, C.W. (1988) Progress in mango cultivation. Proceedings of the Interamerican

Society of Tropical Horticulture 32, 8–19.

Campbell, R.J. and Campbell, C.W. (1992) Commercial Florida mango cultivars. Acta

Horticulturae 341, 55–59.

Chang, M.T. and Lion, M.F. (1987) Delay fruit harvest by pinching mango inﬂ orescence.

In: Chang, L.R. (ed.) Proceedings of the Symposium on Forcing Culture of Horticultural

Crops. Special Publication No. 10, Taichung District Agricultural Improvement

Station, Taichung, Taiwan, pp. 119–128.

Crane, J.H. and Campbell, C.W. (1991) The Mango. Fruit Crops Fact Sheet FC-2, Florida

Cooperative Extension Service, Gainesville, Florida.

Cull, B.W. (1991) Mangos crop management. Acta Horticulturae 291, 154–173.

Davenport, T.L. (1993) Floral manipulation in mangoes. In: Chia, L.E. and Evans,

D.O. (eds) Proceedings on the Conference on Mango in Hawaii. Cooperative Extension

Service, University of Hawaii, Honolulu, Hawaii, pp. 54–60.

Davenport, T.L. (2003) Management of ﬂ owering in three tropical and subtropical fruit

tree species. HortScience 38(7), 1331–1335.

Degani, C., El-Batsri, R. and Gazit, S. (1990) Enzyme polymorphism in mango. Journal of

the American Society for Horticultural Science 115, 844–847.

Duarte, O. (2002) El mango, una opción para Honduras? A Case Study. CCPA, Escuela

Agrícola Panamericana – El Zamorano, Honduras.

Galán Saúco, V. (1979) Actual situation, problems and prospects of mango development

in the Canary Islands. Acta Horticulturae 102, 7–14.

Galán Saúco, V. (1996) Mango world production (outside Israel, Egypt and India). Acta

Horticulturae 455, 1–6.

Galán Saúco, V. (2009) El cultivo del mango. Coedición: Instituto Canario de

Investigaciones Agrarias, La Laguna, Tenerife, España y Ediciones Mundi-Prensa,

Madrid (in Spanish).

References 383

Gazit, S. and Kadman, A. (1980) 13-1 mango root stock selection. HortScience 15, 669.

Hamilton, R.A., Chia, C.L. and Evans, D.O. (1992) Mango Cultivars in Hawaii.

InformationText Series 042, HITAHR, University of Hawaii, Honolulu, Hawaii.

Hayes, W.B. (1966) Fruit Growing in India, 3rd revised edn. Indian Universities Press,

Allahabad, India.

Huete, M. and Arias, S. (2007) Manual para la Producción de Mango. U.S. A.I.D. – RED.

Oﬁ cinas de la FHIA, La Lima, Cortés, Honduras.

Issarakraisila, M., Considine, J.A. and Turner, D.W. (1993) E ects of temperature on

pollen viability in mango cv. Kensington. Acta Horticulturae 341, 112–124.

Ito, P.J., Hamilton, R.A. and Rapoza, H. (1992) ‘Exel’, a High Quality Dessert Mango.

Commodity Fact Sheet 169 MAN-3(B) Fruit, HITAHR, University of Hawaii,

Manoa, Hawaii.

Joel, D.M. (1978) The secretory ducts of mango fruits, a defense system e ective against

Mediterranean fruit ﬂ y. Israel Journal of Botany 27, 44–45.

Johnson, G.I. and Coates, L.M. (1993) Postharvest diseases of mango. Postharvest News

and Information 4, 27N–34N.

Knight, R.J. Jr (1985) Criteria for evaluating important characters in mango (Mangifera

indica L.) germplasm. In: Technology for Agricultural Development: Joint Proceedings

of the 21st Caribbean Food Crops Society and the 32nd Annual Meeting of the American

Society of Horticultural Science, Tropical Region. ASHSTR, Port of Spain, Trinidad,

pp. 57–60.

Knight, R.J. and Schnell, RJ. (1993) Mango (Mangifera indica L.) introduction and

evaluation in Florida and its impact on the world industry. Acta Horticulturae 341,

125–135.

Krishna, H. and Singh, S.K. (2007) Biotechnological advances in mango (Mangifera

indica L.) and their future implication in crop improvement – a review. Biotechnology

Advances 25, 223–243.

Lakshminarayana, S., Gomez-Cruz, A. and Martinez-Romero. S. (1985) Preliminary

study of a new preharvest stem-end rot and associated microﬂ ora in mango.

HortScience 20, 947–948.

Lovey, B.R., Robinson, S.P., Brophy, J.J. and Chacko, E.K. (1992) Mango sapburn

components of fruit sap and their role in causing skin damage. Australian Journal of

Plant Physiology 19, 449–457.

Malo, S.E. (1972) Mango culture in Florida. Acta Horticulturae 24, 149–154.

Malo, S.E. (1976) Recent advances and possibility of mango culture in tropical America

with emphasis on the Florida situation. Acta Horticulturae 57, 47–52.

Malo, S.E. and Campbell, C.W. (1978) Studies on mango fruit breakdown in Florida.

Proceedings of the American Society for Horticultural Science – Tropical Region 22,

1–15.

Mendoza, D.B. and Wills, R.B.H. (eds) (1984) Mango: Fruit Development. Postharvest

Physiology and Marketing in ASEAN. ASEAN Food Handling Bureau, Kuala Lumpur,

Malaysia.

Mostert, P.G. and Abercrombie, R.A. (1998) Soil requirements and soil preparation. In:

de Villiers, E.A. (ed.) The Cultivation of Mangoes. Institute of Tropical and Subtropical

Crops, ACR, LNR, Nelspruit, South Africa, pp. 19–46.

Mukherjee, S.K. (1950) Cytological investigation of the mango and the allied Indian

species. Proceedings of the National Institute of Science India 16, 281–303.

384 References

Nagao, M.A. and Nishina, M.S. (1993) Use of potassium nitrate on mango ﬂ owering. In:

Proceedings of a Conference on Mango in Hawaii. College of Tropical Agriculture and

Human Resources, University of Hawaii, Manoa, Honolulu, Hawaii, pp. 61–66.

Nakasone, H.Y. (1979) Observations and Comments on Tropical Fruit Cultivation. FIRA,

Bank of México, México City (in Spanish).

Nakasone, H.Y., Bowers, F.A.I. and Beaumont, J.H. (1955) Terminal growth and

ﬂ owering behavior of the ‘Pirie’ mango (Mangifera indica L.) in Hawaii. Proceedings

of the American Society of Horticultural Science 66, 183–191.

Nuñez Elisea, R. and Davenport, T.L. (1995) E ect of leaf age, duration and cool

temperature treatment and photoperiod on bud dormancy release and ﬂ oral

initiation in mango. Scientia Horticulturae 62, 63–73.

Oosthuyse, S.A. and Jacobs, G. (1995) Relationship between branching frequency,

and growth, cropping, and structural strength of 2 year old mango trees. Scientia

Horticulturae 64, 85–93.

Pennock, W., Torres-Sepulveda, A., Lopez-Garcia, J., Reyes-Soto, I., Valle-Lamboy, S.,

Cedeno-Maldonado, A. and Jackson, G. (1972) Yield and fruit size comparison

in the ﬁ rst size crops of 16 mango varieties. Journal of Agriculture Puerto Rico 56,

343–365.

Pinto, A.C.Q. and Sharma, D.K. (1984) Studies on growth behavior and sex expression

in some exotic introductions of mango (Mangifera indica L.) in Brazil. Proceedings of

the American Society for Horticultural Science, Tropical Region 28, 25–27.

Pollard, G.V. and Alleyne, E.H. (1986) Insect pests as constraints to the production of

fruits in the Caribbean. In: Brathwaite, C.W.D., Marte, R. and Porsche, E. (eds) Pests

and Diseases as Constraints in the Production and Marketing of Fruits in the Caribbean.

Technical Events Series A2/TT-8 6-001, IICA, Bridgetown, Barbados, pp. 31–61.

Pope, W.T. (1929) Mango Culture in Hawaii. Hawaii Agricultural Experiment Station

Bulletin 58, Honolulu, Hawaii.

Ram, S. and Sirohi, S.C. (1991) Feasibility of high density orcharding in Dashehari

mango. Acta Horticulturae 291, 207–212.

Reuveni, O., Kuepper, W. and Wiebel, J. (1991) Rooting mango cuttings under

intermittent mist, Acta Horticulturae 291, 174–181.

Scha er, B., Whiley, A.W. and Crane, J.H. (1994) Mango. In: Scha er, B. and Andersen,

E. C. (eds) Handbook of Environmental Physiology of Fruit Crops. Vol. II. Subtropical

and Tropical Crops. CRC Press, Boca Raton, Florida, pp. 165–197.

Shawky, I., Zidan, Z., El-Tomi, A. and Dashan, D. (1980) Flowering malformation in

relation to vegetative growth of ‘Taimour’ mangoes. Egypt Journal of Horticulture

7, 1–8.

Singh, L.B. (1960) The Mango – Botany, Cultivation and Utilization. Interscience

Publishers, New York.

Tandon, D.K. and Kalra, S.K. (1983) Changes in sugars, starch, and amylase activity

during development of mango fruit cv. Dashehari. Journal of Horticultural Science

58, 449–453.

Turnball, C.G.N., Anderson, K.L. and Winston, E.C. (1996) Inﬂ uence of gibberellin

treatment on ﬂ owering and fruiting patterns in mango. Australian Journal of

Experimental Agriculture

36, 603–611.

Wainwright, H. and Burbage, M.B. (1989) Physiological disorders in mango (Mangifera

indica L.) fruit. Journal of Horticultural Science 64, 125–135.

References 385

Wenkam, N.S. (1990) Foods of Hawaii and the Paciﬁ c Basin. Fruits and Fruit Products, Raw,

Processed, and Prepared. Vol. 4, Composition. Research Extension Series 110. College

of Tropical Agriculture and Human Resources, University of Hawaii, Honolulu,

Hawaii.

Whiley, A.W. and Saranah, J. (1981) Mango evaluation. In: Biennial Research Report No. 2

for 1979–80. Maroochy Horticultural Research Station, Queensland, Department

of Primary Industries and Forestry, Brisbane, Australia, p. 47.

Whiley, A.W. and Scha er, B. (1997) Stress physiology. In: Litz, R.E. (ed.) The Mango:

Botany, Production and Uses. CAB International, Wallingford, UK, pp. 147–176.

Whiley, A.W., Saranah, J.B., Rasmussen, T.S., Winston, E.C. and Wolstenholme, B.N.

(1988) E ect of temperature on growth of ten cultivars of mango with relevance

to production in Australia. Proceedings of the 4th Australian Conference on Tree and

Nut Crops, pp. 176–185.

Whiley, A.W., Mayers, P.E., Bartley, J.B. and Saranah, J.B. (1993) Breeding mangoes for

Australian conditions. Acta Horticulturae 341, 136–145.

Yee, W. (1958) The Mango in Hawaii. Agriculture Extension Service Circular No. 388,

University of Hawaii, Honolulu, Hawaii.

Young, T.W. and Koo, R.C.J. (1974) Increasing yield of ‘Parvin’ and ‘Kent’ mangos on

Lakewood sand by increasing nitrogen and potassium fertilizer. Proceedings of the

Florida State Horticultural Society 87, 380–384.

Young, T.W. and Sauls, J.W. (1979) The Mango Industry in Florida. Florida Cooperative

Extension Service Bulletin 189, Florida Cooperative Extension Service, Institute of

Food and Agricultural Sciences, University of Florida, Gainesville, Florida.

CHAPTER 11. PAPAYA

Agnew, G.W.J. (1968) Growing quality papayas in Queensland. Queensland Agriculture

Journal 94, 24–36.

Airi, S.K., Gill, S.S. and Singh, S.N. (1986) Clonal propagation of papaya (Carica papaya

L.). Journal of Agriculture Research, Punjab 23, 237–239.

Allan, P. (1964) Papaws grown from cuttings. Farming in South Africa 39(11), 35–40.

An, J.F. and Paull, R.E. (1990) Storage temperature and ethylene inﬂ uences on ripening

of papaya fruit. Journal of the American Society for Horticultural Science 115,

949–953.

Anonymous (2003) FAOSTAT Database. Food and Agriculture Organization of the United

Nations, Rome (accessed 17 February 2010: http://faostat.fao.org/site/339/

default.aspx).

Awada, M. (1958) Relationships of Minimum Temperature and Growth Rate with Sex

Expression of Papaya Plants (Carica papaya L.). Hawaii Agriculture Experiment

Station Technical Bulletin 38, Honolulu, Hawaii.

Awada, M. (1961) Soil moisture tension in relation to fruit types of papaya plants.

Hawaii Farm Science 10(2), 7–8.

Awada, M. (1977) Relations of introgen, phosphorus, and potassium fertilization to

nutrient composition of the petiole and growth of papaya. Journal of the American

Society for Horticultural Science 102, 413–418.

386 References

Awada, M. and Ikeda, W.S. (1957) E ects of Water and Nitrogen Application on

Composition, Growth, Sugars in Fruits, Yield and Sex Expression of the Papaya

Plants (C. papaya L.). Hawaii Agriculture Experiment Station Bulletin 33, Honolulu,

Hawaii.

Awada, M. and Long, C. (1980) Nitrogen and potassium fertilization e ects on fruiting

and petiole composition of 24- to 48-month old papaya plants. Journal of the

American Society for Horticultural Science 105, 505–507.

Awada, M., Suehisa, R.H. and Kanehiro, Y. (1975) E ects of lime and phosphorus on

yield, growth, and petiole composition of papaya. Journal of the American Society for

Horticultural Science 100, 294–298.

Awada, I.P., Suehisa, R.H. and Padgett, M.M. (1979) E ects of drip irrigation and

fertilization on vegetative growth, fruit yield, and mineral composition of the

petioles and fruits of papaya. University of Hawaii, Agricultural Experiment

Station, Honolulu, Hawaii.

Badillo, V.M. (1993) Caricaceae segundo esquema. Alcance 43, Universidad Central de

Venezuela, Facultad de Agronomia, Caracas, Venezuela (in Spanish).

Badillo, V.M. (2000) Carica L. vs. Vasconcella St. Hil. (Caricaceae): con la rehabilitación de

este último. Ernstia 10, 74–79.

Chan, H.T. Jr, Hibbard, K.L., Goo, T. and Akamine, E.K. (1979) Sugar composition of

papaya during fruit development. HortScience 14, 140–141.

Chan, Y.K. (1984) Studies on carpellody of stamens in papaya (C. papaya L.). MARDI

Research Bulletin 12, 157–162.

Chan, Y.K. (1992) Progress in breeding of F

papaya hybrids in Malaysia. Acta

Horticulturae 292, 41–49.

Chan, Y.K. (1993) Memperkenalkan ‘Eksotika’ II: varieti betik hibrid yang lebih baik.

[Introducing the ‘Eksotika’ II: an improved hybrid papaya]. Teknology Buah-buahan

MARDI 9, 25–28.

Chan, Y.K. (2001) Heterosis in Eksotika × Sekaki papaya hybrids. Journal of Tropical

Agriculture and Food Science 29, 139–144.

Chan, Y.K. and Tan, L.K. (1990) Drying treatments in relation to seed germination of

four papaya varieties. MARDI Research Journal 18, 1–7.

Chan, Y.K. and Toh, W.K. (1984) Growth studies on some vegetative characters of

papaya (Carica papaya L.). MARDI Research Bulletin 12, 46–54.

Chen, N.M. and Paull, R.E. (1986) Development and prevention of chilling injury in

papaya fruit. Journal of the American Society for Horticultural Science 111, 639–643.

Chittiraichelvan, R. and Shanmugavelu, K.G. (1979) Studies of the growth and

development of the fruit of CO-2 papaya (Carica papaya L.) II. Changes in biochemical

constituents. Indian Journal of Horticulture 36, 42–48.

Clemente, H. and Marler, T.E. (1996) Drought stress inﬂ uences gas-exchange responses

of papaya leaves to rapid changes in irradiance. Journal of the American Society for

Horticultural Science 121, 292–295.

Conover, R.A., Litz, R.E. and Malo, S.E. (1986) ‘Cariﬂ ora’ a papaya for South Florida and

the Caribbean. HortScience 21, 1072.

Drew, R.A. (1988) Rapid clonal propagation of papaya in vitro from mature ﬁ eld-grown

trees. HortScience 23, 609–611.

Fitch, M.M.M., Manshardt, R.M., Gonsalves, D., Slightom, J.L. and Sanford, J.C. (1992)

Virus resistant papaya plants derived from tissues bombarded with the coat protein

gene of papaya ringspot virus. Biotechnology 10, 1466–1472.

References 387

Hamilton, R.A. (1954) A quantitative study of growth and fruiting in inbred and

crossbred progenies from two Solo papaya strains. Hawaii Agriculture Experiment

Station Technical Bulletin 20.

Higgins, J.S. and Holt, V.S. (1914) The Papaya in Hawaii. Hawaii Agriculture Experiment

Station Technical Bulletin 32, Honolulu, Hawaii.

Hofmeyr, J.D.J. (1938) Determination of sex in Carica papaya. Farming in South Africa 13,

332.

Ito, P.J. (1976) The e ect of leaf pruning on yield and quality of ‘Solo’ papayas in

Hawaii. Proceedings of the Tropical Region, American Society for Horticultural Science

20, 46–50.

Kuhne, F.A. and Allan, P. (1970) Seasonal variation in fruit growth of Carica papaya L.

Agroplantae 2, 99–104.

Lange, A.H. (1961) The e ects of temperature and photoperiod on the growth of Carica

papaya. Ecology 42, 481–486.

Litz, R.E. and Conover, R.A. (1978) In vitro propagation of papaya. HortScience 13,

241–242.

Manshardt, R.M. and Wensla , T.F. (1989a) Zygotic polyembryony in interspeciﬁ c hybrids

of Carica papaya and C. cauliﬂ ora. Journal of the American Society for Horticultural

Science 114, 684–689.

Manshardt, R.M. and Wensla , T.F. (1989b) Interspeciﬁ c hybridization of papaya with

other Carica species. Journal of the American Society for Horticultural Science 114,

689–694.

Marler, T.E. (1994) Papaya. In: Scha er, B. and Andersen, P.C. (eds) Handbook of

Environmental Physiology of Fruit Crops Vol. 2. Subtropical and Tropical Crops. CRC

Press, Boca Raton, Florida, pp. 216–224.

Marler, T.E. and Discekici, H.M. (1997) Root development of ‘Red Lady’ papaya plants

grown on a hillside. Plant & Soil 195, 37–42.

Mekako, H.U. and Nakasone, H.Y. (1975) Interspeciﬁ c hybridization among 6 Carica

species. Journal of the American Society for Horticultural Science 100, 237–242.

Morshidi, M. (1996) Genetic variability in Carica papaya and related species. PhD

dissertation, University of Hawaii at Manoa, Honolulu, Hawaii.

Mosqueda-Vazquez, R., Aragaki, M. and Nakasone, H.Y. (1981) Screening of Carica

papaya L. seedlings for resistance to root rot caused by Phytophthora palmivora Butl.

Journal of the American Society for Horticultural Science 106, 484–497.

Nakasone, H.Y. and Aragaki, M. (1973) Tolerance to Phytophthora fruit and root rot in

Carica papaya L. Proceedings Tropical Region American Society for Horticultural Science

17, 176–185.

Nakasone, H.Y. and Storey, W.B. (1955) Studies on the inheritance of fruiting height

of Carica papaya

L. Proceedings of the American Society for Horticultural Science 66,

168–182.

Paull, R.E. and Chen, N.J. (1990) Heat shock response in ﬁ eld grown ripening papaya

fruit. Journal of the American Society for Horticultural Science 115, 623–631.

Qiu, Y.X., Nishina, M.S. and Paull, R.E. (1995) Papaya fruit growth, calcium uptake,

and fruit ripening. Journal of the American Society for Horticultural Science 120,

246–253.

Quintana, M.E.C. and Paull, R.E. (1993) Mechanical injury during postharvest handling

of ‘Solo’ papaya fruit. Journal of the American Society for Horticultural Science 118,

618–622.

388 References

Seo, S.T., Farias, G.J. and Harris, E.J. (1982) Oriental fruit ﬂ y: ripening of fruit and its

e ect on index of infestation of Hawaiian papayas. Journal of Economic Entomology

75, 173–178.

Storey, W.B. (1938) Segregations of sex types in Solo papaya and their application to

the selection of seed. Proceedings of the American Society for Horticultural Science 35,

83–85.

Storey, W.B. (1941a) Part I. The botany and sex relationships of the papaya. In: Papaya

Production in the Hawaiian Islands. University of Hawaii, Hawaii Agriculture

Experiment Station Bulletin 87, Honolulu, Hawaii.

Storey, W.B. (1941b) Genetics of sex determination in papaya. Hawaii Agriculture

Experiment Station Annual Report 1940, 52–53.

Storey, W.B. (1958) Modiﬁ cation of sex expression in papaya. Horticulture Advance 2,

49–60.

Storey, W.B. (1969) Papaya (Carica papaya L.). In: Ferwerda, P. and Wit, F. (eds) Outline

of Perennial Crop Breeding in the Tropics. H. Veenman and Zonen, Wageningen, The

Netherlands, pp. 389–407.

Subhadrabandhu, S. and Nontaswatsri, C. (1997) Combining ability analysis of some

characters of introduced and local papaya cultivars. Scientia Horticulturae 71,

203–212.

Van Droogenbroeck, B., Breyne, P., Goetghebeur, P., Romeijn-Peeters, E., Kyndt, T. and

Gheysen, G. (2002) AFLP analysis of genetic relationships among papaya and

its wild relatives (Caricaceae) from Ecuador. Theoretical and Applied Genetics 105,

289–297.

Wenkam, N.S. (1990) Foods of Hawaii and Paciﬁ c Basin Fruits and Fruit Products: Raw,

Processed, and Prepared. Vol. 4. Composition. Research and Extension Series 110,

College of Tropical Agriculture and Human Resources, Honolulu, Hawaii.

Yee, W. (1970) Papayas in Hawaii. Circular 436, Cooperative Extension Service, University

of Hawaii, Honolulu, Hawaii.

CHAPTER 12. PINEAPPLE

Aldrich, W.W. and Nakasone, H.Y. (1975) Day versus night application of calcium

carbide for ﬂ ower induction in pineapple. Journal of the American Society for

Horticultural Science 100, 410–413.

Antoni, M.G. and Leal, F.J. (1980) Species of the genus Ananas: origin and geographic

distribution. Tropical Region, American Society for Horticultural Science 24, 103–106

(in Spanish).

Antoni, S., Grazia, M. and Leal, F. (1980) Key to the identiﬁ cation of commercial varieties

of pineapple (Ananas comosus). Proceedings of the Tropical Region, American Society

for Horticultural Science 24, 107–112 (in Spanish).

Aradhya, M.K., Zee, F. and Manshardt, R.M. (1994) Isozyme variation in cultivated and

wild pineapple. Euphytica 79, 87–99.

Armstrong, J.W. and Vargas, R.I. (1982) Resistance of pineapple variety 59-650 to ﬁ eld

populations of Oriental fruit ﬂ ies and Melon ﬂ ies (Diptera: Tephritidae). Journal of

Economic Entomology 75, 781–782.

Bartholomew, D.P. (1977) Inﬂ orescence development of pineapple (Ananas comosus (L.)

Merr). induced to ﬂ ower with ethephon. Botanical Gazette 138, 312–320.

References 389

Bartholomew, D.P. and Criley, R.A. (1983) Tropical fruit and beverage crops. In: Nichells

L.G. (ed.) Handbook of Plant Growth Regulating Chemicals, Vol. II. CRC Press, Boca

Raton, Florida.

Bartholomew, D.P. and Kadzimin, S.B. (1977) Pineapple. In: Alvim, P.T. and Kozlowski,

T.T. (eds) Ecophysiology of Tropical Crops. Academic Press Inc., New York,

pp.113–156.

Bartholomew, D.P. and Malézieux, E. (1994) Pineapple. In: Scha er, B. and Andersen,

P. (eds) Handbook of Environmental Physiology of Fruit Crops. CRC Press Inc., Boca

Raton, Florida, pp. 243–291.

Bartholomew, D.P. and Paull, R.E. (1986) Pineapple. In: Monselise, S.P. (ed.) CRC Handbook

of Fruit Set and Development. CRC Press, Boca Raton, Florida, pp. 371–388.

Bartholomew, D.P., Malézieux, E., Sanewski, G.M. and Sinclair, E. (2003) Inﬂ orescence,

and fruit development and yield. In: Bartholomew, D.P., Paull, R. and Rohrbach,

K.G. (eds) The Pineapple: Botany, Production and Uses. CABI Publishing, Wallingford,

UK, pp. 167–202.

Brewbaker, J.L. and Gorrez, D.D. (1967) Genetics of incompatibility in monocotyledonous

genera Ananas (pineapple) and Gasteria. American Journal of Botany 54, 611–616.

Chan, Y.K. and Lee, C.K. (1985) The hybrid 1 Pineapple: a new canning variety developed

at MARDI. Teknologi Buah-buahan (Malay) 1, 24–30.

Chan, Y.K., Coppens d’Eeckenbrugge, G. and Sanewski, G.M. (2003) Breeding and

variety improvement. In: Bartholomew, D.P., Paull, R. and Rohrbach, K.G. (eds)

The Pineapple: Botany, Production and Uses. CABI Publishing, Wallingford, UK, pp.

33–55.

Collins, J.L. (1933) Morphological and cytological characters of triploid pineapples.

Cytologia 4, 248–256.

Collins, J.L. (1948) Pineapples in ancient America. Science Monthly 65, 372–377.

Collins, J.L. (1949) History, taxonomy and culture of the pineapple. Economic Botany 3,

335–359.

Collins, J.L. (1960) The Pineapple: Botany, Cultivation and Utilization. Interscience

Publishers Inc., New York.

Collins, J.L. and Kerns, K.R. (1938) Mutations in the pineapple. Journal of Heredity 29,

162–172.

Coppens d’Eeckenbrugge, G. and Leal, F. (2003) Morphology, anatomy and taxonomy.

In: Bartholomew, D.P., Paull, R. and Rohrbach, K.G. (eds) The Pineapple: Botany,

Production and Uses. CABI Publishing, Wallingford, UK, pp. 13–32.

Coppens d’Eeckenbrugge, G., Leal, F. and Duval, M.F. (1997) Germplasm resources of

pineapple. Horticultural Reviews 21, 133–175.

Ekern, P.C. (1968) Phyllotaxy of pineapple plants and fruit. Botanical Gazette 129,

92–94.

Evans, D.O., Stanford, W.G. and Bartholomew, D.P. (1988) Pineapple. Commodity Fact

Sheet PIN-3(A), College of Tropical Agriculture and Human Resources, Hawaii

Institute of Tropical Agriculture and Human Resources, Manoa, Hawaii.

Friend, D.C. and Lydon, J. (1979) E ect of daylength on ﬂ owering, growth and CAM of

pineapple (Ananas comosus (L.)). Botanical Gazette 140, 280–283.

Gowing, D.P. (1961) Experiments on the photoperiodic response in pineapple. American

Journal of Botany 48, 16–21.

Hepton, A. (2003) Culture system. In: Bartholomew, D.P., Paull, R. and Rohrbach, K.G.

(eds) The Pineapple: Botany, Production and Uses. CABI Publishing, Wallingford, UK,

pp. 109–142.

390 References

Hepton, A. and Hodgson, A.S. (2003) Processing. In: Bartholomew, D.P., Paull, R. and

Rohrbach, K.G. (eds) The Pineapple: Botany, Production and Uses. CABI Publishing,

Wallingford, UK, pp. 281–290.

Krauss, B.H. (1948) Anatomy of the vegetative organs of the pineapple, Ananas comosus

(L) Merr. I. Introduction, organography, the stem, and the lateral branches or

axillary buds. Botanical Gazette 110, 159–217.

Krauss, B.H. (1949) Anatomy of the vegetative organs of the pineapple, Ananas comosus

(L) Merr. II. The leaf. Botanical Gazette 110, 333–404.

Lacoeuilhe, J.J. (1975) Etudes sur le contrÔle du cycle de l’ananas en Côte d’Ivoire. Fruits

30, 307–312.

Leal, F.J. and Soule, J. (1977) ‘Maipure’, a new spineless group of pineapple cultivars.

HortScience 12, 301–305.

Lim, W.H. (1985) Diseases and Disorders of Pineapples in Peninsular Malaysia. MARDI

Report #97, Kuala Lumpur, Malaysia.

Loison-Cabot, C. (1992) Origin, phylogeny and evolution of pineapple species. Fruits

47, 25–32.

Malézieux, E. and Bartholomew, D.P. (2003) Plant nutrition. In: Bartholomew, D.P.,

Paull, R.E. and Rohrbach, K.G. (eds) The Pineapple: Botany, Production and Uses.

CABI Publishing, Wallingford, UK, pp.143–165.

Malézieux, E., Zhang, J.B., Sinclair, E.R. and Bartholomew, D.P. (1994) Predicting

pineapple harvest date in di erent environments, Amiga computer simulation

models. Agronomy Journal 86, 609–617.

Malézieux, E., Cote, F. and Bartholomew, D.P. (2003) Crop environment, and vegetative

physiology and growth. In: Bartholomew, D.P., Paull, R.E. and Rohrbach, K.G. (eds)

The Pineapple: Botany, Production and Uses. CABI Publishing, Wallingford, UK, pp.

69–107.

Nightingale, G.T. (1942) Nitrate and carbohydrate reserves in relation to nitrogen

nutrition of pineapple. Botanical Gazette 103, 409–456.

Okimoto, M.C. (1948) Anatomy and histology of the pineapple inﬂ orescence and fruit.

Botanical Gazette 110, 217–230.

Paull, R.E. (1993) Pineapple and papaya. In: Seymour, G., Taylor, J. and Tucker, G. (eds)

Biochemistry of Fruit Ripening. Chapman & Hall, London, pp. 291–323.

Paull, R.E. and Chen, C.-C. (2003) Postharvest physiology, handling, and storage of

pineapple. In: Bartholomew, D.P., Paull, R.E. and Rohrbach, K.G. (eds) The Pineapple:

Botany, Production and Uses. CABI Publishing, Wallingford, UK, pp. 253–279.

Paull, R.E. and Reyes, M.E.Q. (1996) Preharvest weather conditions and pineapple fruit

translucency. Scientia Horticulturae 66, 59–67.

Paull, R.E. and Rohrbach, K.G. (1985) Symptom development of chilling injury

in pineapple fruit. Journal of the American Society for Horticulture Science 110,

100–105.

Py, C., Lacoeuilhe, J.J. and Teisson, C. (1987) The Pineapple. Cultivation and Uses. G.-P.

Maisonneuve, Paris.

Rodriguez, A.G. (1932) Inﬂ uence of smoke and ethylene on the ﬂ owering of pineapple

(Ananas sativas Shult). Journal of the Department of Agriculture, Puerto Rico 26,

5–18.

Rohrbach, K.G. (2003) History, distribution and world production. In: Bartholomew,

D.P., Paull, R.E. and Rohrbach, K.G. (eds) The Pineapple: Botany, Production and Uses.

CABI Publishing, Wallingford, UK, pp. 1–12.

References 391

Rohrbach, K.G. (Undated) Pineapple. The Plant and its Culture. Hawaii Institute of Tropical

Agriculture and Human Resources, Honolulu, Hawaii.

Rohrbach, K.G. and Apt, W.J. (1986) Nematode and disease problems of pineapple. Plant

Disease 70, 81–87.

Rohrbach, K.G. and Johnson, M. (2003) Pests, diseases and weeds. In: Bartholomew,

D.P., Paull, R.E. and Rohrbach, K.G. (eds) The Pineapple: Botany, Production and Uses.

CABI Publishing, Wallingford, UK, pp. 203–251.

Rohrbach, K.G. and Schmitt, D.P. (1994) Pineapple. In: Plotz, R.C., Zentmyer, G.A.,

Nishijima, W.T. and Rohrbach K.G. (eds) Compendium of Tropical Fruit Diseases. APS

Press, St. Paul, Minnesota, pp. 45–55.

Sanford, W.G. (1962) Pineapple crop log-concept and development. Better Crops Plant

Food 46, 32–43.

Sanford, W.G. (1964) Factors inﬂ uencing the interpretation of the crop log. In. Bould,

C., Prevot, P. and Magness, J.R. (eds) Plant Analysis and Fertilizer Problems. W.F.

Humphrey Press, Geneva, New York, pp. 255–267.

Sether, D.M. and Hu, J.S. (2002) Closterovirus infection and mealybug exposure are

necessary for the development of mealybug wilt of pineapple disease. Phytopathology

92, 928–935.

Sideris, C.P. and Krauss, B.H. (1936) The classiﬁ cation and nomenclature of groups of

pineapple leaves, sections of leaves and sections of stems based on morphological

and anatomical di erences. Pineapple Quarterly 6, 135–147.

Soler, A. (1992) Metabolisme de l’ethephon dans l’épiderme de l’ananas (Ananas comosus

(L.) Merr.). Fruits 47, 471–477.

Teisson, C. (1979a) Le brunissement interne de l’ananas. I. Historique. II. Matériel et

méthodes. Fruits 34, 245–261.

Teisson, C. (1979b) Le brunissement interne de l’ananas. III. Symptomatologie. IV.

Approche biochimique du phénomène. Fruits 34, 315–339.

Wenkam, N.S. (1990) Foods of Hawaii and the Paciﬁ c Basin Fruits and Fruit Products: Raw

Processed, and Prepared Vol. 4. Composition. College of Tropical Agriculture and

Human Resources Research Extension Series No. 110, Honolulu, Hawaii.

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393

INDEX

Page numbers in bold refer to ﬁ gures, tables and maps.

abscission 5, 232

acetylene 120, 352

allelopathy 37

Annona species

breeding

cultivars 134–136

genetics 133–134

problems 134

commercially important species 123–124

defoliation 97

diseases 144–146

ecology 127–129

family 123

fertilization 143–144

ﬂ owers 130–131

fruit 132–133

composition 151

growth regulators for fruit setting 132

harvesting 148–149

postharvest handling 149–150

ripening 150

use 150

growth and management practices

ﬁ eld preparation for planting 139

pruning 76, 141–142

sweetsop and atemoya 141

transplanting and spacing 139–140

weed management 147–148

insect pests 146–147

irrigation 140

origin, distribution and

morphology 124–126

pollination 131–132, 134

by hand 99

humidity and temperature

requirements 127

propagation

methods 136–137, 139

rootstock and scion compatibility 138,

139

aphids: barriers against 60

apomixes 64

aroma: e ects of temperature 109

atemoya see Annona species

auxins 98

avocado

breeding

cultivars 164, 165

genetics 164–165

methods 166

selection 166–167

commercially important species 153–154

diseases 176–178

ecology 156–158

family 153

fertilization 175–176

ﬂ owers 160–162

fruit 163–164

composition 184

harvesting 180–182

postharvest handling 182–183

use 183

growth and management practices

ﬁ eld preparation for planting 173

integrated crop management

(ICM) 177–178

pruning 175

transplanting and spacing 173–174

weed management 179–180

insect pests 178–179, 180

irrigation 174–175

morphology 159

394 Index

avocado – continued

origin and distribution 154–156

phenological cycle 160

pollination 162–163

propagation

cuttings 171

grafting 171–173

seedlings 170–171

rootstocks 167–168

tree characteristics 158, 160

bacteria, pathogenic 93

bagging 100

banana and plantain

breeding

cultivars 186, 188, 196, 197–198

genetics 195

problems 195–196

selection 196

diseases 209, 210–211, 212

drainage 42–43

ecology 187–189, 190

fertilization 204–205, 207

ﬂ owers 192–193

fruit

composition 219

harvesting 214–215

marketing 217–218

postharvest handling 215–216

ripening 217, 218

soil nutrients removed 206

use 218–220

genus 185–187

growth and development 194, 195

e ect of pseudostem height 207

growth and management practices

bunch covers 208

cableways 202

ﬁ eld preparation for planting 200

high-density annual planting 201–202,

207

pruning and bunch propping 203

sucker management and leaf

removal 203–204

transplanting and spacing 200–201

weed management 214

windbreaks 214

irrigation 84, 202–203

morphology

fruit 193–194

plant 189–190, 191, 192

origin and distribution 187

pests 212, 213, 214

propagation 67, 68, 199–200

pruning 78

barriers

against pests 60, 90, 91

against wind 57–59, 214, 295, 321

beds, raised 42

bees 99

beetles: pollinators 131

beta-carotene 7

biodiversity 1

birds 60

boron 315

branching 72

breakdown, internal 287

budding: propagation method 68

bunches (banana and plantain)

covers 208

propping 203

bunchy top (disease) 316

cableways 202

carambola

pollination 99

vulnerability to wind 25, 27

carbohydrate 6

carpellody 299, 301, 305

cherimoya see Annona species

chlorﬂ urenol 346

climate

change 31

classiﬁ cation 15–17

day length 19–20

deﬁ nition 11

e ect of altitude 18

rainfall see rainfall

solar radiation 15

subtropics 18–19

temperature 20–23

types in tropics 17–18

winds, frost and hail 24–27

Codex Alimentarius: nutrient claims 7

condensation: during storage 112

consumers: expectations and knowledge 8, 9

containers 71

corms 69, 199–200

cultivars

Annona species 134–136

avocado 164, 165, 169–170

banana 186, 188, 196, 197–198

litchi and longan 237–238, 239–241

mango 265, 266–267, 268–269, 287

Index 395

papaya 309–311

pineapple 329, 330, 343–345

cuttings 66

cyclones 25, 26

defoliation 97

dichogamy 98, 99

diseases 93–94

Annona species 144–146

avocado 176–178

banana and plantain 209, 210–211, 212

litchi and longan 246–247

mango 280, 281, 282

papaya 315–316, 317–318, 319

resistance 304, 309

pineapple 353, 355, 356

resistance 343

postharvest 117–118

disinfection: of pruning tools 77–78

disinfestation, postharvest 117, 250, 282,

322

distribution: spread of fruit through migration

of people 2

drainage 41–43

energy: content in fruit 6

ethephon 231, 275, 352, 359

ethylene 105, 106, 353

for postharvest ripening 119–120, 183,

217, 286

evapotranspiration 84

evolution, fruit 4–5

fatigue, soil 37

fertilizers

application

diluted solutions 88

foliar 88–89, 350

solids 87–88

timing 87

foliar nutrient analysis 143, 144

needs and dosages 84, 86

soil and plant analysis 85, 87

species requirements

Annona 143–144

banana and plantain 204–205, 207

litchi and longan 244–245

mango 274–275

papaya 315

pineapple 350–351, 352

ﬁ eld capacity (FC) 82

ﬂ avour: e ects of temperature 109

ﬂ ooding 24, 41

ﬂ owering

Annona species 130–131

avocado 160–162

banana and plantain 192–193

e ect of photoperiod and

temperature 19–20, 256

induction 96, 98, 232–233, 275–278,

351–353

litchi and longan 228–230

mango 256, 275–278

pineapple 89, 339–340, 351–353, 360

species characteristics 72

folate 7

follicle 5

forums, international 8–9

fruit ﬂ ies 90, 282–283

fungi 93, 209

gibberellins 98

anti-gibberellins 277, 278

girdling 95–97, 160, 231, 277

grafting 68

green manures 53

ground covers 53

growth: regulators 97–98, 132, 277–278

guava

ﬂ owers 19

pruning 76

vulnerability to wind 25

HACCP 118–119

handling, postharvest 116–117

Annona species 149–150

avocado 182–183

banana and plantain 215–216

generalized scheme 102

litchi and longan 249–250

mango 285–287

objective 103

pineapple 360–361

postharvest physiological

disorders 362–363

harvesting 116

Annona species 148–149

avocado 180–182

banana and plantain 214–215

litchi and longan 248–249

mango 285

papaya 321–322

pineapple 359–360

396 Index

herbicides 55–56

horticulture: limitations in tropics 9–10

humidity, relative for storage 111, 112–113

imports 8

injuries

chilling 106–107, 113, 286–287, 323,

362

mechanical 113–114

insects 90–92

pest target species

Annona 146–147

avocado 178–179

banana and plantain 212, 213

litchi and longan 247–248

mango 282–283, 284, 285

papaya 319–320

pineapple 357, 358

postharvest disinfestation 117, 250, 282,

322

integrated crop management (ICM) 177–178

integrated pest management (IPM) 95

intercrops 50–51

International Society of Horticultural Science

(ISHS) 9

International Tropical Fruit Network

(TFNet) 9

irradiation 250, 321

irrigation

and plantation layout 43

control 82–84

determination of demand 24

individual species needs

Annona 140

avocado 174–175

banana and plantain 202–203

litchi and longan 243

mango 271–272

papaya 313–314

low-pressure 80–81

of steep land 39

pineapple 348–350

sprinkler 81–82

sub-irrigation 82

surface 79–80

water quality 36–37

kinetin 231

Köppen, Wladimir: climate classiﬁ cation 15,

kudzu 52

layering 67

leaves

defoliation 97

foliar nutrient analysis 143, 144

papaya 296

pineapple 338

removal of dead leaves 204

limb braces 25

liming 36

litchi and longan

breeding

cultivars 237–238, 239–241

genetics 236

selection 236, 239

diseases 246–247

ecology 223–225, 226

factors a ecting fruiting cycle 224

family 221–222

ﬂ owers 226–230

fruit

composition 251

erratic bearing 245–246

growth and development 233–235

harvesting 248–249

postharvest handling 249–250

retention after setting 231

seedless fruit 231–232

use 250–251

growth and management practices

chemical regulators 230–233

fertilization 244–245

ﬁ eld preparation 242

girdling 97, 231

pruning 243–244

transplantation and spacing 242–243

weed management 248

insect pests 247–248

limb braces 25

moisture requirements 23–24

morphology 227, 229

tree 225–226

origin and distribution 222

pollination 230

propagation 241–242

temperature requirements 22

logistics 120–121

longan see litchi and longan

losses, postharvest 101–102

macadamia 99

mango

breeding

Index 397

cultivars 265, 266–267, 268–269, 287

genetics 264

problems 264–265

diseases 280, 281, 282

ecology 21, 23–24, 254–256

family 252

fertilization 274–275

ﬂ owers 257–259

induction 97, 275–278

fruit

composition 289

growth and development 263–264

harvesting 283

marketing 288

morphology 261, 263

postharvest handling 285–287

use 288–290

yields 257, 278–280

growth and management practices

chemical regulators 261–263

ﬁ eld preparation 271

pruning 272–274

weed management 285

growth retardants 98

induction of ﬂ owering 98

insect pests 282–283, 284, 285

irrigation 271–272

marketing and production 268

morphology 253

origin and distribution 252, 254

pollination 259–260

polyembryony 260–261

propagation 270–271

pruning 75

rootstocks 269

tree characteristics 257

mangosteen

tolerant to ﬂ ooding 24

manure, green 53

marcottage 67

market analysis: in establishment of new

orchards 33–34

mites 92, 180, 319–320, 357

monsoon 25

morphology

atemoya 126

cherimoya 124–125

pond apple 126

sweetsop 125–126

mulching 54

nematodes 94, 212, 213, 214, 321, 355, 356

control by soil fumigation 347

nitrates: for ﬂ owering induction 277–278

nurseries: management 69–70

nutrients, dietary

contents in fruits 6–7, 151, 184, 219,

251, 289, 325, 364

e ects of storage 108–109

orchards

establishment

drainage 41–43

irrigation water quality 36–37

land preparation 39–41

land selection 34, 35

mountainous land 39

planning 37–39

plantation layout 43–44, 45

planting see planting

previous land usage 37

role of market analysis 33–34

soil evaluation 36

ﬂ oor management 52–54

organic fruit 120

paclobutrazol 277, 278

papaya

breeding

cultivars 309–311

genetics 303–307

objectives 307–309

transgenic varieties 307

diseases 315–316, 317–318, 319

resistance 304, 309

ecology 292–295

ﬂ owers 296, 298–299, 301

types 300

fruit 302–303, 304

characteristics 305–307

composition 325

harvesting 321–322

marketing 323–324

postharvest handling 322–323

use 324–325

world production 324

growth and management practices

fertilization 315

ﬁ eld preparation 312

orchard protection 321

propagation 311–312

pruning 314–315

transplanting and spacing 313

weed management 321

398 Index

papaya – continued

growth characteristics 298

intolerant to ﬂ ooding 24

irrigation 313–314

leaves 296

morphology 297

origin and distribution 292

pests

insects and mites 319–320

nematodes 321

pH tolerance 30, 293

pollination 301–302

stem 295–296

taxonomy and nomenclature 291

vulnerability to wind 25

passion fruit

pollination 99

vulnerability to wind 25

peach

problems with orchard replantation 37

permanent wilting point (PWP) 83

pests 10

barriers 60

e ects of climate change 31

insects see insects

integrated pest management 95

nematodes 94

postharvest disinfestation 117

vertebrates 95

pH, soil 30–31, 36, 293

phosphorus

deﬁ ciency in soil 27, 29

photoperiod 13, 19, 128, 189, 256, 335–336

physiology, postharvest

chilling injury 106–107

ethylene production 105, 106

moisture loss 107–108, 109

respiration 104–105, 106, 107

unique characteristics of tropical

fruits 103–104

pineapple

breeding

cultivars 329, 330, 343–345

genetics 342

selection 342–343

diseases 353, 355, 356

resistance 343

ecology 24, 330–336

ﬂ owering induction 98, 351–353, 354

fruit

composition 364

e ect of precocious ﬂ owering on

production 360

growth and development 340–341

harvesting 359–360

morphology 337

postharvest handling 360–361

postharvest physiological

disorders 362–363

standards 361

use 363–365

weight at harvest versus plant weight at

forcing 354

growth and management practices

fertilization 350–351, 352

ﬁ eld preparation for planting 346–347

planting 347–348

soil fumigation 347

spacing 348, 349

weed management 357, 359

irrigation 348–350

leaves 338

morphology 328

ﬂ owers 19–20

fruit 337

roots 337–338

stem 336–337

origin and distribution 329

pests

insects and mites 357, 358

nematodes 347, 355, 356

propagation 63, 67, 68, 345–346

taxonomy and nomenclature 327–328

wind damage 25

plantain see banana and plantain

planting

associated crops and intercrops 50–51

high-density annual 201–202, 207

layout 43–44, 45

material 48–50

procedure 46–48, 70, 347–348

spacing 44, 46, 47

Annona species 140

avocado 173–174

banana and plantain 200–201

litchi and longan 242–243

papaya 313

pineapple 348, 349

pluviometers 83

pollination 162–163, 166, 230, 260–261,

301–302

by beetles 131

y hand 98–99, 128, 131–132

cross-pollination 131, 134

temperature and humidity

requirements 127

Index 399

polyembryony 260–261

potassium

content in fruit 7

production, fruit

2007 world statistics 4

world trends and projections 7–8

propagation

di erences betwen sexually and asexually

propagated trees 69

importance to trade 63

litchi and longan 241–242

methods

cuttings 66

for various crops 65, 66, 136–137, 139,

199–200, 241–242, 270–271,

311–312, 345–346

grafting and budding 68

layering 67

sexual (seed) 64–65

tissue culture 67, 200, 312

natural propagative structures 68–69

to ensure quality 63

protein 6

pruning

Annona species 141–142

avocado 175

banana and plantain 203

cuts and tools 77–78

formation pruning 71, 73, 74

litchi and longan 243–244

mango 272–274

papaya 314–315

production pruning 74–76

rationale 70–71

sanitary and maintenance 76

structural regeneration 76–77, 78

to change a variety 77

quality

deﬁ nition 101

major logistical issue 120–121

objective of postharvest handling 101

of fruit

consumer expectations 8

of plants 48–49

radiation, solar 15, 20, 158, 189, 190,

294–295, 334–335, 336

temporary shade 98–100

rain gauges 83

rain shelters 100

rainfall

amount available to plants 23

patterns in the tropics 13, 14, 23

quantity and distribution 23–24

species preferences

Annona species 127

avocado 156–157

banana and plantain 187–188

litchi and longan 223

mango 254–255

papaya 293

pineapple 331–332

rainforest 17

regulators, chemical 97–98, 230–231,

261–263, 346

respiration, postharvest 104–105, 106, 107

ripening 119–120, 183, 217, 286

pre-harvest 359

rodents 95

roots

development in containers 70

e ect of soil on development 40

pineapple 337–338

rootstocks

Annona species 138, 139

avocado 167–168

mango 269

rotation, crop 37

safety, food 118–119

salinity 156, 293

plant tolerance 38, 168

sap burn 287

savannah

climate 17–18

scoring 95–97, 277

seedlings 69–70

seeds

use in production 64–65

use in selection 63

selection

seeds versus vegetative material 63

shrink 101

smudging 275

sodium naphthalene acetate (SNA) 230–231

soil

analysis 85

classiﬁ cation and characteristics 27–31

deﬁ ciencies 27, 29, 30–31

distribution of soil types in tropics 28, 29

e ect of ﬂ ooding 41

e ect on root development 40

400 Index

soil – continued

evaluation 36

fatigue 37

fumigation 347

land selection for orchards 34, 35

moisture content 23

problems in tropics 10

species preferences

Annona species 127

avocado 156

banana 127

litchi and longan 223

mango 254

papaya 292–293

pineapple 331

standards 116, 286, 361

storage

chilling injury 106–107, 113, 286–287,

323, 362

controlled and modiﬁ ed

atmosphere 114–116, 250, 286, 323

e ects on ﬂ avour and aroma 109

mechanical injury 113–114

moisture loss 107–108, 109, 112–113,

113

on-tree 180–181

potential 110, 111

relative humidity 111, 112–113

temperature 108, 110–111, 183, 361

vitamin C loss 108–109

storms 26

subsoiling 40

subtropics

use for tropical fruit crops 21

suckers 68–69, 199–200, 336–337

management 203–204

sweetsop see Annona species

taxonomy 3

temperature

chilling injury 106–107, 113, 286–287,

323, 362

cold resistance 167

e ect on ﬂ owering 20, 161, 257

e ects on ﬂ avour and aroma 109

factors of inﬂ uence 20–21

for storage 108, 110–111, 183, 249, 250

in tropics 11, 13

postharvest cooling 117

species preferences 21–23

Annona species 127–128

avocado 157–158

banana and plantain 188–189

litchi and longan 224–225, 226

mango 255–256

papaya 293–294

pineapple 332–334

tensiometers 81, 83

TFNet (International Tropical Fruit

Network) 9

thiourea 277

Thornthwaite, C.W.: climate classiﬁ cation 15

time domain reﬂ ectometry (TDR) 83

tissue culture 67, 200, 312

traps, insect 90, 91

trees: as windbreaks 57–58, 59

tropics

characteristics 1

deﬁ nition and characteristics of region 11,

13–15

distribution of tropical and subtropical

regions 12

uniconazole 277, 278

urea 231

viruses and viroids 94, 316, 319

vitamin C 7

loss on storage 108–109

weeds: management 54–56

Annona species 147–148

avocado 179–180

banana and plantain 214

litchi and longan 248

mango 285

papaya 321

pineapple 357, 359

winds 24–27, 56–57

susceptible species

Annona species 128

banana and plantain 189, 214

mango 257

windbreaks 57–59, 214, 295, 321