Tropical Fruit

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 21. Blueberries J. Retamales and J.F. Hancock

22. Peppers: Vegetable and Spice Capsicums, 2nd Edition P.W. Bosland and E.J. Votava

2ND EDITION, VOLUME II

Robert E. Paull

Tropical Plant and Soil Sciences

University of Hawaii at Manoa

Honolulu, HI, USA

and

Odilo Duarte

Retired Professor - Escuela Agrícola Panamericana

El Zamorano, Honduras

Now: Professor and Lead Scientist in Agribusiness

CENTRUM Católica Business School

Pontifi cia Universidad Católica del Perú, Lima, Perú

Nosworthy Way Wallingford

Oxfordshire OX10 8DE UK Tel: +44 (0)1491 832111 Fax: +44 (0)1491 833508 E-mail: info@cabi.org Website: www.cabi.org 875 Massachusetts Avenue 7th Floor Cambridge, MA 02139 USA T: +1 800 552 3083 (toll free) T: +1 (0)617 395 4051 E-mail: cabi-nao@cabi.org

© R.E. Paull and O. Duarte 2012. All rights reserved. No part of this 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 Cataloging-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-13: 978 1 84593 789 8

Commissioning editor: Sarah Hulbert Editorial assistant: Chris Shire Production editor: Simon Hill

Typeset by Columns Design XML, Reading. Printed and bound in the UK by MPG Books Ltd.

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vii Volume I presented the general aspects of tropical fruit production and covered the major tropical fruit in international trade such as banana, pineapple, papaya, mango and avocado. Many other tropical fruit, already well-known in the tropics, are now appearing in larger temperate city markets. In this volume, we have selected those that are being increasingly seen in overseas markets outside of the tropics.

The choice of crops to present in Volume II was the greatest challenge, especially in the last three chapters dealing with other Asian and Pacifi c, African and American Fruits. The fruit crops covered in these last three chapters is the tip of what is available and that have considerable potential as fruit crops. A number of the chapter fruit sections show the signifi cant gaps in our knowledge of managing these fruit crops in large orchards and not backyard production. A major gap is lack of breeding eff ort to develop varieties suitable for intensive production that have disease and insect resistance, high yield and desired fruit quality that suit diff erent growing environments and consumer markets.

We have followed the same chapter layout used in the fi rst edition and Volume I of this edition. 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.

Many have contributed to the endeavour. Encouragement and help of Henry in this passion came from many and acknowledged in the First and Second Editions. Numerous comments and suggestions from colleagues have been incorporated. All errors and omissions are our responsibility. The illustrations of many of the crops covered in this Volume and for Volume I were done by Susan Monden in Honolulu. The family of Dr. Jorge Leon granted us permission to use the fi gures from ‘Botánica de los Cultivos Tropicales’. Dr. Lionel Robineau, coordinator TRAMIL gave us permission

to use the Hylocereus drawing and Dr. Mike Nagao the use of the Pulasan picture. Mrs. Meg Coates Palgrave kindly agreed to let us use the Marula drawing from Trees of Central Africa though we are unable to render it in colour. The editor of Flore Analytique du Bénin let us use the ackee drawing. Thanks are also due to the Commissioning Editor Sarah Hulbert and Christopher Shire at CABI for their 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 address in the front of the text 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 that enabled us to complete this undertaking.

Robert E. Paull Honolulu, USA. 2012 Odilo Duarte Lima, Peru. 2012

ix The authors gratefully acknowledge the support, information, and ideas supplied by Jeff Anderson, Alton Bailey, Jit Baral, Lou Biad, Chris Biad, Anna Biad, Judy Bosland, Emily Bosland, Will Bosland, Emma Jean Cervantes, Danise Coon, Deyuan Wang, Natalie Goldberg, Max Gonzalez, Wendy Hamilton, Steve Hanson, John Hard, Sue Hard, Jaime Iglesias, Sanjeet Kumar, Jimmy Lytle, Jo Lytle, Ariadna Monroy, Mary O’Connell, Jaebok Park, Jennifer Randall, Adrian Rodriquez, Robert Steiner, Ousmane Sy, Betty Terrien, Nankui Tong, Manju Vishwakarma, Stephanie Walker, April Ulery, Everardo Zamora, and the Chile team at New Mexico State University.

© Paull and Duarte 2012. Tropical Fruits, 2nd Edition, Volume II 1 (R.E. Paull and O. Duarte)

A

NNONAS

: S

OURSOP AND

R

OLLINIA

BOTANY

Family

Both soursop and Rollinia belong to the Annonaceae, commonly referred to as the custard-apple family. The family consists of about 75 genera that are now widely distributed. Some Annona species are grown as ornamentals, while others are known for their edible fruit and perfume.

Important genera and species

The soursop belongs to the most important genus Annona, which among its more than 100 species has seven species and one hybrid that are grown commercially worldwide. Soursop is the most tropical of these species and has the largest fruit. Rollinia (or biriba) belongs to the closely related genus Rollinia and it is not as well known as soursop. The two most important commercial species are cherimoya and sweetsop. Along with the hybrid, atemoya, all three are discussed in Chapter 6 of Volume 1.

Annona muricata L. is known as soursop in English and guanábana in most Spanish-speaking countries. It is also known as catoche (Venezuela), zapote agrio, zapote de viejas or cabeza de negro (Mexico), guayabano (Philippines), nangka belanda zuurzak or sisrsak (Indonesia), thurian-khaak (Thailand), sitaphal (India), fruta de conde, graviola, jaca do Pará (Brazil), nona sri kaya or durian belanda (Malaysia) and corossol epineux (France).

The synonyms for Rollinia mucosa (Jacq.) Baill. are R. orthopetala A. DC. or R. deliciosa Saff ., R. pulcherrima A. DC. and Annona mucosa Jacq. (Sousa, 2008). Other names are biribá, fruta da condessa or beribá (Brazil) (Manica, 2000), anona babosa or zambo (Mexico), anón (Peru), chirimoya (Ecuador),

mulato (Colombia), cachiman cochon or cachiman montagne (Guadalupe), anón cimarrón (Puerto Rico), anonillo (Panama) and candongo (Dominican Republic).

Area of origin and distribution

Soursop is the most tropical of and produces the largest fruit among the Annona species. The Caribbean is the area of origin, although soursop was distributed very early to the warm lowlands of eastern and western Africa and to south-east China. It is commonly found on subsistence farms in south-east Asia, and was established very early in the Pacifi c islands.

Soursop is considered well suited to processing and for use in local markets for fresh consumption. It is grown extensively in Mexico, from Culiacan to Chiapas, and from Veracruz to the Yucatan Peninsula in the Gulf region. Large orchards are seen in this region, with a total of more than 6000 ha being grown. Venezuela has around 4000 ha, Brazil more than 2000 ha and Peru almost 500 ha. Colombia and Ecuador have also developed some modern orchards in the last few years for the local fruit markets and for industrial use. Exports of fresh fruit are very low.

Rollinia originated in the forests of the Brazilian Amazon in the states of Acre, Rondônia and the Antilles. It has been spread throughout Brazil and other South American countries, as well as Florida (Manica, 2000; Donadio et al., 2002). This species, apparently cultivated since pre-Columbian times, is not widely cultivated for commercial purposes; rather, it occurs in backyard orchards or small plantings.

ECOLOGY

Soil

Soursop, as with most Annona species, is capable of growing in a wide range of soil types, from sandy soil to clay loams (Pinto et al., 2005). Nevertheless, higher yields occur on more well-drained sandy to sandy loam soils. Drainage is essential to avoid root rot. A. glabra is of interest as a rootstock because of its tolerance to fl ooded soils. Soursop can withstand some drought, but will experience fl ower abscission. The ideal soil pH is 5–6.5.

Rollinia also prefers well-drained deep soils with a good content of organic matter but it can grow in poor acid soils high in exchangeable aluminum. The tree can withstand periodic fl ooding (Sousa, 2008).

Climate

Rainfall

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. Under very rainy conditions, as occurs in parts of Costa Rica, soursop has many leaf and fruit disease problems and is not normally grown commercially. In Colombia, soursop will grow successfully under rainfall conditions that can consist of two rainy seasons a year or just one. The alternating rainy and dry seasons have a positive eff ect on fl ower initiation. In addition, dry periods favor some leaf fall that results in new vegetative growth. Well-distributed yearly precipitation of 500–1500 mm results in adequate production, depending on its distribution. Yields are low when the rainfall is less than 500 mm (Duarte 1997; SCUC, 2006).

Rollinia grows in hot, humid climates where a short dry period can occur, but in many cases monthly rainfall can be as high as 300 mm during the rainy season. It probably tolerates heavy rainfall areas better than the other fruit-producing species of this family. It needs at least 1500 mm of rainfall, and in many areas in the Amazon valley it will grow with more than 2700–3000 mm (Donadio et al., 2002).

Temperature

Temperature is a major limiting factor to production, with frost killing young trees while older trees show some tolerance. Soursop is the least tolerant of the Annona species (15–25°C mean minimum). Donadio et al., (2002) has reported that Rollinia can withstand mild frosts in the Jaboticabal area of Brazil, where the plant will defoliate in the winter. Soursop grows best under average temperatures of 25–28°C. It can be grown at elevations of up to 1000 m in the tropics and subtropics, as long as winter temperatures do not drop below 15°C. The temperature range for Rollinia is 1–2°C higher than for soursop, and it prefers the hot, humid tropics. Poor pollination, a frequent problem with all Annona species, occurs with high temperatures (30°C) and low humidity (30% relative humidity [RH]), even with hand pollination. Lower temperatures (25°C) and high humidity (80% RH) greatly improve pollination.

Light and photoperiod

Light penetration to the base of vigorous trees with a dense canopy in close spacing can be 2% of full sunlight, and there is very little fruit set. The soursop plant also tends to have a conic upright form. Pruning practices and spacing need to be adjusted to ensure light penetration. No photoperiod responses have been reported for any Annona species.

Wind

The soft wood of the trees makes them susceptible to wind damage and limb breakage. Wind may also be partially responsible for the penetration of collar-rot organisms. Productivity can be improved by windbreaks and under-tree sprinkling to raise the RH above 60%.

GENERAL CHARACTERISTICS

Tree

The soursop is a small, evergreen tree that is slender and upright or low-branching and bushy. It grows to heights of 4.5–9 m. Glossy, dark-green leaves are alternate, simple and entire, with an obovate to elliptic shape, and are 12.7–20 cm long (Fig. 1.1). The leaves emit a strong odour when crushed.

Rollinia generally reaches 6–10 m in height, but can grow as high as 20 m with a trunk diameter of 60 cm. The wood is soft, and the round or conic canopy is formed by branches that tend to grow vertically with laterals forming at their bases. The plant is semi-deciduous, with alternate oblong or elliptical oblong leaves, 12–20 cm long and 8–10 cm wide with an acuminated apices base. The leaves are leathery and the petioles are 6–12 mm long. Flowers occur once a year after leaf fall.

Flowers

The fl owers of Annona species are hermaphroditic and are produced singly or in small clusters on the current season’s growth, although fl owers arising in ‘cushions’ from old wood are not uncommon. All lateral buds can have up to two vegetative buds and three fl ower buds. Soursop lateral buds are exposed in the leaf axil (Fig. 1.1), while the lateral buds of atemoya, cherimoya and sweetsop are normally ‘buried’ (subpetiolar). Adventitious buds can arise at any point on the trunk. New fl owers continue to appear toward the apex of the shoot as fl owers produced earlier at the basal portions mature.

Soursop fl owers are pale yellow and 2.5–4 cm long, with three thick, fl eshy petals and three smaller inner petals alternating with the outer petals (Fig. 1.1). They have a peculiar odor. Defoliation of A. muricata manually or with ethephon spray promotes lateral branch growth and induces additional fl ower formation near the apex of the branches. Rollinia fl owers are solitary or form small clusters on the current season’s growth (Moncur, 1988). They have three sepals and six petals. The external petals have the form of wings and give the fl ower the appearance of a propeller (Fig. 1.2A). They form a tubular structure at their junction in the center of the fl ower (Villachica et al., 1996).

Annona species generally require 27–35 days for fl ower-bud initiation to anthesis. In A. squamosa, fl owering can extend from 3–6 months or even longer, with heavy peaks. Two major fl owering periods occur after periods of vegetative fl ushes, with the second peak coinciding with the onset of the monsoon season in India (Kumar et al., 1977). Flowering can occur year round with a continuous warm climate and water availability, while harvest becomes more seasonal in the subtropics.

Pollination and fruit set

Natural pollination

The fl owers exhibit both dichogamy and a protogynous nature (Pinto et al., 2005). This poses a serious problem in obtaining high yields. A. muricata fl oral anthesis takes place mostly between noon and 8 pm and from 4 am to 8 am, with pollen release occurring between 4 am and 8 am (Moncur, 1988).

Escobar and Sánchez (1992) have given a detailed description of the timing of the pollination process, dividing it into four phases that can take between 96 and 132 h. In phase I, the fl ower button opens slightly at the basal point of contact of the outer petals. Sexual structures are whitish and stigmatic liquid starts to become apparent and viscous, indicating the fl ower is receptive. In phase II, after 48–60 h the tips and bases of the outer petals have separated, the fl ower is more receptive since more stigmatic liquid is present, and the stamens become yellow, normally in the morning as the fl ower reaches its fi nal size. In phase III, after another 24–48 h, the outer petals are semi-open and have a yellow-greenish color and more stigmatic liquid. The stamens have a dark-yellow color and the pollen is viable. Phase IV is reached 24 h later, when the outer petals are completely open and have acquired a sulfur color. Stigmatic liquid becomes less viscous and the fl ower is still receptive. The anthers are now cream in color and release viable pollen. The inner petals do not open, but are slightly separated in phases III and IV. After this all the petals, stamens and stigmata fall in 12–24 h, with the calyx, receptacle and peduncle remaining attached.

Natural pollination in soursop is complex and in most cases results in very low fruit set and yields, with wind- and self-pollination being low (1.5%). The nitidulid beetles (Carpophilus and Uroporus spp.) are considered important pollinators of Annona fl owers, although no signifi cant eff ect has been observed from their presence in some cases. These beetles breed very fast in the remains of fruit, so it is recommended to maintain the rotting fruit attractant. Some reports have indicated that the presence of three nitidulid beetles per fl ower can increase fruit set by 25% (SCUC, 2006).

In the case of Rollinia, the fl owers are also protogynous and the two female and male phases do not overlap to allow for self-pollination (Moncur, 1988). The petals open only slightly during the female stage. Insects are attracted by the scent, but nectar is not produced. Later on, the male-stage fl owers open widely and insects forage for the pollen. All of this leads to poor fruit set. In Brazil, four species of leaf beetles (Chrysomelidae) pollinate the fl owers with only 32% fruit set (Morton, 1987).

Hand pollination

Hand pollination is used to overcome poor pollination. Hand pollination is often very effi cient, resulting in signifi cant economic returns from the higher fruit set and larger and more symmetrical fruit. Hand pollination has also proven to be eff ective in Rollinia (Moncur, 1988). The pollen grains of fl owers appearing early in a fl owering season have thick walls and are high in starch, germinate poorly and give poor fruit set. The pollen of later fl owers shows a high proportion of individual pollen grains without starch grains, and these germinate well.

Pollen is obtained from opened fl owers collected between 4 and 5 pm when the sacs have turned from white to cream. Flowers on thin branches or at the end of such branches should be harvested for pollen collection. Pollen can be obtained directly from picked fl owers held in a paper bag or cardboard box, not a sealed container, at phase IV. Flowers picked at phase III will release pollen the next morning. Pollen from both stages can then be mixed for use. When the fl owers are shaken over a shallow tray or in a plastic jar, the stamens and pollen separate and the pollen will stick to the jar walls. The pollen is then transferred to a small container. Pollen obtained in the afternoon can be held in a refrigerator for use the next morning. The moist pollen is applied to fl owers in phase III or IV using a hair brush or even by rubbing the pollen on the stigma with an index fi nger. Some people remove one of the inner petals to make it easier to apply the pollen. Flowers can be tagged to keep control of the process. Pollination is performed between 6 and 10 am, and earlier if the days are hot and dry.

Success in hand pollination is sometimes variable, being less successful on very humid overcast days and with young, vigorous trees. About 150 fl owers can be pollinated by a skilled laborer in 1 h with a success rate of 80–100%. Flowers for hand pollination should preferably be taken from strong branches at the center of the canopy of trees older than 4 years.

Growth regulators for fruit set

Hand pollination in commercial orchards is tedious, time-consuming and costly. Attempts have been made to use growth regulators to regulate fruit set, with considerable variations in response. Auxin-induced fruit grow very slowly with less fruit drop, while gibberellic acid promotes fruit set and growth rate; however, it does not assist in post-set retention (Yang, 1988).

Fruit

The soursop fruit is a syncarp that varies from less than 0.4 kg to more than 4.5 kg, with some fruits reaching 12 kg. The size depends on genotype, extent of pollination and fertilization. A normal fruit is generally heart-shaped to oval (Fig. 1.3), but poor pollination results in unfertilized ovules that lead to small, distorted, irregular shapes. The skin is dark green with many recurved, soft spines. The fl esh is juicy and white with a cottony texture, and contains many dark brown seeds that are about 2 cm long. The pulp has an agreeable sub-acid fl avor with a distinct aroma. Soursop produces fruit throughout the year, but in most areas peak production is during summer and early autumn, sometimes with a secondary peak in the early spring.

The Rollinia fruit is also a syncarp that generally weighs from 200 to 1000 g (Fig. 1.2B) and sometimes up to 4 kg. The fl avor is like that of the soursop, but it is sweeter and less acidic; the aroma is also appreciated by consumers. The weight of 1000 seeds is about 315 g. The ripe fruit normally has a yellow skin and the pulp is cream or white, mucilaginous, soft and juicy.

Fruit growth shows the typical sigmoidal curve, with maturation occurring in 16–24 weeks, depending on the species and growing conditions (Fig. 1.4). 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 temperatures can cause premature fruit ripening and fermentation of the fruit.

CULTIVAR DEVELOPMENT

Genetics, cytogenetics and breeding

The chromosome numbers of most Annona species are 2n = 14 or 16. A desirable hybrid would be between cherimoya and soursop. This would combine the larger fruit size and acidity of soursop with the sweetness, fl avor and texture of cherimoya. 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 with breeding

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

Time from Anthesis (weeks)

)

Fig. 1.3. Fruit of soursop, sweetsop and atemoya.

Fig. 1.4. Increase in fruit diameter from anthesis for soursop, sweetsop and

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. Breeding programs 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 Annona species, since most plantings have been of seedlings. In many Latin American countries, fi eld selections have been made separating the sweet (actually less acid) from the acid fruited types. There are also diff erences in fruit form, color and consistency (juicy and hard). These two groups are recognized in Colombia, with the sweet type having fruits of about 1 kg, while the acid can have fruits of up to 5 kg. Producers in Costa Rica selected some superior types that were given names and are now being propagated clonally. Selections have also been made in Brazil, where cultivars (‘Morada’, ‘Lisa’ and ‘Blanca’) have also been introduced from Colombia. Of these, ‘Morada’ has the highest yields per tree (up to 40 kg) and the largest size of fruit (3–10 kg). It also has fi rm pulp, a sub-acid fl avor and is more tolerant to fruit and stem borers, which makes it the most desirable cultivar (Pinto and da Silva, 1996). Brazilian selections include ‘Cerradinha,’ ‘Ibrimirina,’ ‘Gigante de Alagoas’ and ‘FAO II.’

Rollinia has apparently seen no breeding programs, although some selections have been made in Brazil by the native tribes. Some selections produce fruit that weigh 4 kg (Clement et al., 1982).

CULTURAL PRACTICES

Propagation

The Annona species are usually propagated by seed. The recalcitrant seeds rapidly lose viability (6 months) and should be sown as soon as possible after removal from the fruit. Seeds can take up to 30 days to germinate and gibberellic acid signifi cantly increase germination and enhance seedling growth. Annona seedlings require at least 3–4 years to bear fruit (Sanewski, 1991).

Clonal propagation by cuttings, layering, inarching, grafting and budding have been tried for many of the Annona species. In some reports, grafting is superior to budding in percentage takes and subsequent growth, with side-whip and cleft graft techniques giving the best results. Escobar and Sánchez (1992)

found patch budding to be the best, with an 82.5% success rate for soursop, while the side graft was second with lower success rates with A. muricata, A. reticulata and A. montana. Cleft graft and inverted ‘T’ budding did very poorly for all four rootstocks. The success of cleft and side grafting or inverted ‘T’ and patch budding was practically zero with A. squamosa. The branches should be defoliated 1–2 weeks before scion wood is cut to induce bud swelling, and petioles should be left on the branch. There are considerable graft incompatibilities among Annona species.

Rollinia is normally propagated by seeds that germinate in about 1 month. Seedling growth is very fast during the initial years. In some cases, grafting has been used successfully (Sousa, 2008).

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.

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 be performed if there is a risk of frost. Plants should have attained a height of 30–50 cm at transplanting, with the union of grafted or budded plants placed approximately 15 cm above the ground. Trees should be irrigated as soon as possible after transplanting, and wind and sun guards are sometimes required.

Soursop trials suggest spacings of 4–4.6 u 6–7 m do not aff ect growth or interfere with cultural practices. Spacings of 6–7 u 6–8 m are also used. A triangular layout is recommended whatever planting distance is selected, with the rows running north to south to avoid shading. For Rollinia, a 6 u 6 m or 7 u 7 m spacing is normally used (Vargas et al., 1999).

Irrigation practices

Annona species are grown without irrigation in many areas where rainfall is well distributed. Except for pond apple (A. glabra), most Annona species can stand periods of drought and prefer rather dry conditions. Adequate soil

moisture is required to encourage vegetative growth, however, since fl owering occurs on new growth. The amount and frequency of irrigation is determined by experience for a particular location and soil type. Water stress should be prevented during fl owering, fruit set and fruit development, as fruit are more sensitive than leaves.

High soil moisture to increase humidity during the fl owering season may prolong stigma receptivity and fruit set and growth. Low-rise sprinklers beneath the tree canopy during fl owering can increase humidity. The stomata of Annona species respond to RH not water stress. They will continue to lose water if the humidity is greater than 80%, making maintenance of soil moisture crucial (Marler et al., 1994).

Annona species, especially soursop and sweetsop, can show hardening of the fruit pulp with brownish lumps apparently caused by the sudden movement of water into the fruit (George et al., 1987). The eff ect is enhanced by boron defi ciency. This disorder is reported as being common in north-eastern Brazil under conditions with limited or no irrigation. As in most crops, any water stress slows plant growth and decreases fruit size. Water quality is also important. Sodium chloride can negatively aff ect growth, especially at a leaf concentration of 0.3% sodium and can cause leaf burn and defoliation. Elevated levels of chlorine and boron in the water are phytotoxic to fruit and leaves, and are diffi cult to control (Pinto and da Silva, 1996).

Pruning

Training of trees begins 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, after which it should be headed back to produce lateral branches. The lateral branches should be spaced 15–25 cm above each other and allowed to grow in diff erent directions to develop a good scaff old. After about 2 m, trees are left to grow naturally. Pruning is carried out when the trees are dormant. For heavy fruit-bearing trees, pruning involves the removal of lower limbs that touch the ground and branches in the center that may be rubbing against each other. The aim is to allow sunlight access to the center of the tree.

The soursop will, by nature, usually produce a symmetrically conical tree and is well adapted to the central-leader system. It has an erect habit of growth, and thus height has to be controlled if trees are to remain short to make harvest and other tree-management practices easier. An alternative is to develop a mushroom-shaped tree that is topped at 2–2.6 m. The fruit in this system are borne on the lateral branches and hang down for ease of harvest. This process starts with formation pruning, where plants are topped at 60–80 cm once they start growing following transplanting. After topping, three or four primary

branches are selected so that they are evenly spaced around the trunk and care is taken that they do not arise too close together so that no weak zone occurs. These primary branches can be topped at about 50 cm from their origin to induce secondary branching. When properly trained, little pruning is required except to thin out poorly placed and weak branches. To contain trees within a certain space allocation and height limitation, the longest branches extending horizontally and vertically may be pruned annually, preferably immediately after harvest. Plants should not be allowed to grow above 2.5–4 m, depending on the formation method used.

Diseased or insect-infested branches should be removed periodically, as should branches growing in the wrong direction or with undesirable sprouting. Any excess vegetation inside the canopy should be removed to allow greater light penetration and ventilation. Rejuvenation by heavy pruning is occasionally needed, but very severe pruning reduces subsequent fruiting.

Fertilization

Annona species have an indeterminate growth habit (axillary fl owering) and applying nitrogen in a somewhat excessive amount does not greatly interfere with fl oral initiation, as is the case with plants with a determinate growth habit. However, excessive tree vigour is usually associated with reduced fl ower-ing and yields in many trees.

Fertilization starts in the nursery, with in particular nitrogen applied in small amounts. During transplanting some fertilizer, especially phosphorus, is added to the bottom of the hole. In the vegetative growth period prior to fruiting, phosphorus, potassium and sometimes calcium from dolomitic rock are usually applied. Avilán (1975) found that soursop has a high requirement for phosphorus and potassium. According to Pinto and da Silva (1996) a 10:15:15 or 10:13:15 ratio is adequate for growth and production. The fertilizer (250 g) of any of these formulas is applied in four applications (approximately 63 g each) per tree per year, during the fi rst 4 years. In the fi fth and following years, this amount is increased to 1 kg/tree applied over four applications. Observations in Hawaii and Mexico have indicated the desirability of providing 1.3 kg of a triple-15 fertilizer formulation during the fi rst year of production, split into two applications. Each year thereafter, up to approximately the sixth bearing year, the total amount can be increased by approximately 0.45 kg/tree/ year.

In Brazil, a recommendation of 40 g nitrogen per tree in the fi rst year to 180 g in year 5 and thereafter has been made. For phosphorus, the recommendation was none for the fi rst year to 40–180 g/tree/year in year 5 and thereafter; and for potassium, from 30–60 g/tree in the fi rst year to 60–180 g/tree/year after year 5, with the amounts being related to soil analysis results (Table 1.1).

Another recommendation suggests that non-irrigated bearing plants should be fertilized with 3 kg ammonium sulfate, 660 g triple superphosphate and 500 g potassium chloride (SCUC, 2006). This is applied in three equal portions during the year, preferably at the start, the middle and toward the end of the rainy season. The fertilizer should be lightly incorporated into the soils around the tree. Soursop also responds well to manure applications: either 15 kg per plant of decomposed cow manure or 3–4 kg of decomposed poultry manure.

In cool subtropical areas, most vegetative growth takes place during the warmer months from spring to autumn. A reduction in nitrogen during the winter minimizes new vegetative growth in young trees that are vulnerable to cold temperatures.

As with other perennial fruit trees, soil and plant tissue analyses are the techniques most used to evaluate the nutritional state of the plants. Soil sampling in adult soursop orchards should be similar to that recommended for other crops. For leaf sampling, the recommended method depends on the age of the plant, the position of the leaf in the canopy and on the branch and, as with many fruit crops, whether the branches are fruiting or not. Pinto and da Silva (1996) recommended collecting 8- to 9-month-old leaves that are free from fertilizer or agrichemical residues. The sample should consist of about 100 leaves for every 5–7 ha. Four leaves should be obtained from each of 25 randomly selected plants. The orchard should be divided into smaller plots according to soil characteristics. Samples should not be taken from sick or abnormal plants. Flowering time and periods of heavy rain should be avoided. Select plants of similar size and age, and avoid recently fertilized plants.

Normal leaf concentrations for nitrogen and potassium in Brazil are 1.6- to 2.0-times greater than those from defi cient leaves. Comparing data from Avilán (1975) and Silva and Silva (1997), there is a greater diff erence in Venezuela than in Brazil between normal and defi cient leaves with regard to nitrogen, while the variation is less for potassium (Table 1.2).

Table 1.1. Nitrogen (N), phosphorus (P) and potassium (K) requirements for soursop

according to the age of the plant and the availability of soil phosphorus and potassium (Silva and Silva, 1997).

Age (years) N (g/plant)

P-resin (g/dm3_{) K-exchangeable (g/dm}3₎ 0–10 11–20 >20 0–45 46–90 >90 P2O5 (g/plant) K2O (g/plant) 0–1 40 0 0 0 60 40 30 1–2 80 80 60 40 80 60 40 3–4 120 120 80 60 120 80 60 >4 180 120 80 40 180 120 60

Pest management

Diseases

A number of diseases of soursop have been reported (Table 1.3). Anthracnose, caused by Colletotrichum gloeosporioides, is the most serious disease on soursop, particularly in areas of high rainfall and humidity and during the wet season in dry areas. This disease causes twig dieback, defoliation and dropping of fl owers and fruit. On mature fruit, the infection causes black lesions. Black canker (Phomopsis annonacearum) 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 P. annonacearum, while B. theobromae causes twig dieback. Diplodia rot has darker internal discoloration and causes deeper, more extensive corky rot in fruit. Cylindrocladium fruit and leaf spot is caused by a soil-borne fungus, C. colhounii. It 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 the fruit become unmarketable. Control measures recommended are good orchard sanitation with heavy mulching and lower-branch pruning to prevent splashing of soil during heavy rainfall (Sanewski, 1991).

Table 1.2. Leaf nutrient concentration for soursop in Venezuela and Brazil.

Element Concentration Venezuela (Avilán, 1975) Brazil (Silva et al., 1984) Nitrogen (g/kg) Normal 17.6 25–28 Defi cient 11.0 13–16 Phosphorus (g/kg) Normal 2.9 1.4 Defi cient 1.1 0.6–0.7 Potassium (g/kg) Normal 26.0 26.1 Defi cient 12.6 26.4 Calcium (g/kg) Normal 17.6 10.8 Defi cient 10.8 4.5 Magnesium (g/kg) Normal 0.2 1.5–1.7 Defi cient 0.08 1.1–1.3 Boron (mg/kg) Normal – 35–47 Defi cient – 6–14

Insects

Insect pests of soursop occur in numerous growing areas (Table 1.4). One of the most serious insects in Mexico, Central America, Trinidad, Surinam, Colombia, Venezuela and Brazil is the Cerconota moth, which lays its eggs on young fruit. The emerging larvae tunnel into the pulp, causing blackened, necrotic areas. It is not uncommon to fi nd every fruit larger than 7.5 cm infested. For this moth, the use of light traps is recommended, as well as picking and burying fallen fruit. The use of specifi c approved insecticides and the release of parasitoid have also proven eff ective (Escobar and Sánchez, 1992). The Bephrata or Bephratelloides wasp is also widely distributed through-out the Caribbean, Mexico, Central America and central and northern Sthrough-outh

Table 1.3. Major diseases of soursop.

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 luteobubalina Roots, base of trees, decline

Australia Bacterial wilt Pseudomonas

solanacearum

Tree wilt Australia

Black canker (diplodia rot)

Botryodiplodia theobromae

Leaf scorch, twig dieback, peel blackening, graft union rotting

Universal

Black canker Phomopsis annonacearum

As for diplodia rot Australia Purple blotch Phytophthora palmivora Spots on immature

fruit, fruit drop, twig dieback

Australia

Rust fungus Phakopsora cherimoliae Leaves Florida

Fruit rot Gliocladium roseum Fruit India

Rhizopus rot Rhizopus stolonifer Fruit Brazil

Seedling rot Rhizoctonia solani Cylindrocladium spp.

America. This wasp is considered to be the most important pest in Florida. Considerable damage to the soursop fruit has been observed in Mexico and Central America by the authors. The larvae infest the seeds and damage the pulp as they bore through the fl esh to emerge when the fruit matures. Control measures include preventive spays with approved products during initial fruit growth. For both of these insects, very good control can be obtained by bagging the fruit using plastic bags either with holes or with the basal end open (Escobar and Sánchez, 1992; Broglio-Micheletti et al., 2001).

The Thecla moth is widespread throughout parts of the Caribbean and in the American tropics, but it is not considered to be as serious a pest as the Cerconota moth and Bephrata wasp. Damage is primarily to the fl owers. The larvae feed on fl ower parts, such as the perianth, stamen and stigmas, and the fl owers fail to set fruit.

Mature-green annonaceous fruit have been shown to be rarely infested by the Mediterranean fruit fl y (Ceratitis capitata) and the Oriental fruit fl y (Dacus dorsalis), but they are found occasionally in tree-ripened fruit. Bait sprays and fi eld sanitation are recommended measures to minimize fruit-fl y infestation. Fruit bagging also provides protection.

Table 1.4. Major insect pests of soursop.

Common name Organism Parts affected Country/region Bephrata wasp

(soursop wasp)

Bephrata meculicollis Fruit Mexico, Americas, Trinidad, Surinam Wasp Bephratelloides paraguayensis Fruit Americas, Barbados Cerconota moth (soursop moth)

Cerconota anonella Fruit Americas, Trinidad, Surinam

Thecla moth Thecla ortygnus Flowers, young fruit

Americas, Caribbean Banana spotting Amblypelta 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 Queensland fruit fl y Bactrocera tryoni Fruit Australia

Potato leaf hopper Empoasca fabae Leaves Caribbean Red spider mite Several genera,

species

Leaves, fl owers

American tropics Scale insects Saissetia coffeae Leaves, stem Universal Coconut scale Aspidiotus destructor,

other genera and species

Mealy bugs and various species of scale insects are found universally and usually become serious pests on neglected trees. The former is reported to be a major pest on marketable fruit in some areas of Australia (Sanewski, 1991). Red spider mites can become a serious problem in dry areas or during dry seasons. Heavy infestations have been observed on soursop fl owers and leaves in the Tecomán area of Mexico during the prevailing dry period, with trees showing heavy fl ower drop.

Weed management

Problem weeds, especially grasses and twining weeds, should be controlled before planting by cultivation and herbicides. Young trees should be protected from weed competition by hand weeding, mulching or contact herbicides. Shallow root systems limit the use of cultivation under the tree.

HARVESTING AND POSTHARVEST HANDLING

Harvesting season, yield and harvesting

The harvesting season is quite similar in most areas, especially for soursop and sweetsop, diff ering only in range (Table 1.5). A major problem in soursop cultivation is obtaining commercial yields and large fruit with a symmetrical shape. To increase fruit set and size and achieve a better shape, hand pollination has become an important aspect of cultivation practices in

Table 1.5. Peak harvesting seasons for soursop.

Country/region Month(s)

Caribbean Year round

Brazil, center May–September Brazil, north-east Year round

Florida June–November

Hawaii January–October

Indonesia Year round

Mexico June–September

The Philippines June–August

Colombia Year round

some areas. Rootstocks have been shown to greatly infl uence yield (Sanewski, 1991).

In Hawaii, soursop yields from trees grown in a marginal fi eld have shown approximately 43 kg/tree on 4-year-old trees, increasing to 83 kg/tree on 6-year-old trees. In Paramaribo, Surinam, soursop yields of 54 kg/tree at 278 trees/ha have been reported.

Fruit is harvested when fully mature and fi rm. The skin-color changes as the fruit approaches maturity. The immature soursop fruit is dark green and shiny, losing its sheen and becoming slightly yellowish-green on reaching maturity. 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. Harvesting is more diffi cult and time-consuming for soursop, because the trees are generally taller than those of other Annona species and the fruit are much larger. In large soursop orchards, mechanical harvesting aids are feasible and accelerate handling.

Rollinia fruit turn yellow at maturity and should be harvested before they start to change color or as the process starts, but before they are completely ripe. Ripe fruit are soft and diffi cult to handle. The fruit should be harvested very carefully by cutting the peduncle with a sharp knife or pruning shears. Yields can vary from 25 to 60 fruit/tree/year for 5-year-old trees, while 15-year-old trees can produce 100–150 fruits/year (Vargas et al., 1999). Harvesting in Brazil is normally done between January and June, 4 months after fl ower anthesis.

Postharvest handling

Harvested fruit should be handled with care to prevent bruising of the skin. This is especially important for fruit that are marketed for fresh consumption. Firm soursop fruit need to be held after harvest for 4–7 days at room temperature, with optimum quality processing occurring 5–6 days after softening begins (Paull, 1983). The skin of the ripening soursop fruit will gradually turn dark brown to black, but the fl esh is unspoiled. Storage temperatures below 15°C cause chilling injuries and a failure to develop full fl avor. Pre-cooling of fruit is essential to help extend the shelf life. Protuberances on the skin of fully ripe Rollinia are easily injured and they turn brown to almost black, making the fruit unattractive (Morton, 1987).

When processed, soursop fruit are stored on racks in the shade and inspected daily. All fruit that yield to fi nger pressure are removed for processing. Slightly immature fruit will ripen but they lack the full fl avor and aroma, and nectars prepared from the puree of such fruit have a fl at taste. Pulp-recovery percentages have been reported to range from 62% to 85.5% (Paull, 1982).

Diff erences in recovery percentages are caused by diff erences in equipment, extraction methods, cultivar and cultural practices, including environmental infl uences. The number of seeds per fruit also infl uences pulp recovery.

Compositional changes during fruit ripening

All Annona species bear climacteric fruit. Soursop respiration begins to increase within a day of harvest and reaches its peak at days 6–8. Ethylene production is initiated approximately 48 h after initiation of the respiration rise, and reaches its peak at about the same time as the respiration peak reaches a plateau (Paull, 1983). Total soluble solids increase from around 10% to 16% during the 3 days of ripening. The major titratable acids are malic and citric acids. Days 6 and 7 are considered to be the optimum edible stage and coincide with the peak of ethylene production.

UTILIZATION

Soursop fruit is marketed fresh to local markets. This fruit, of all the Annona species, has the best processing potential because of the excellent fl avor characteristic of the pulp and high recovery from large fruit. Unfortunately, soursop has to be hand peeled and cored, an expensive and time-consuming operation. The fragility of the skin and the fruit’s irregular shape and softness limit machine processing.

Soursop pulp is viscous and requires dilution to produce a desirable nectar viscosity; however, this diluted product is fl at and weak. To overcome this dilution eff ect, the pH needs to be adjusted to 3.7 by adding citric acid and sugar to 15% total soluble solids to create a desirable balance between acidity, sweetness and fl avor. Unsweetened and sweetened soursop pulp processed below 93°C show no changes in organoleptic properties. Freeze preservation produces a higher-quality product. Enriched pulp, sweetened or unsweetened, can be processed and stored frozen for re-manufacture as various products or reconstituted directly by the consumer. Puree can be used to prepare an iced soursop drink or mixed with other juices, or it can be made into sherbets and gelatin dishes. Soursop is a good source of potassium, ribofl avin and niacin (Table 1.6).

Rollinia pulp is normally eaten fresh, though in some parts of Brazil it is used to make a fermented wine. Sugar can be added to the pulp to make some desserts. The seeds have insecticidal properties (Vargas et al., 1999).

FURTHER READING

Bayogan, E.R. and Paull, R.E. (2008) Soursop Annona muricata. In: Janick, J. and Paull, R.E. (eds) The Encyclopedia of Fruit and Nuts. CAB International, Wallingford, UK, pp. 42–46.

Campbell, C.W. (1985) Cultivation of fruits of the Annonaceae in Florida. Proceedings of the Tropical Region of the American Society for Horticultural Science 29, 68–70. Coelho de Lima, M.A. and Alves, R.E. (2011) Soursop (Annona muricata L). In: Yahia,

E.M. (ed) Postharvest Biology and Technology of Tropical and Subtropical Fruits. Volume 4: Mangosteen to White Sapote. Woodhead Publishing Ltd., Cambridge, pp. 363– 391.

Love, L., Paull, R.E. (2011) Rollina. University of Hawaii at Manoa, College of Tropical Agriculture and Human Resources. Fruit and Nuts Publication F_N-21. Available from: http://www.ctahr.hawaii.edu/oc/freepubs/pdf/F_N-21.pdf. Accessed August 20, 2011.

Table 1.6. Composition of 100 g edible portion of soursop

(Wenkam, 1990) and Rollinia (Collazos et al., 1975, cited by Villachica et al., 1996).

Constituent Soursop Rollinia

Proximate Water (g) 80.10 85.0 Energy 247 kJ 53.0 cal Protein (g) 0.69 1.1 Fat (g) 0.39 0.4 Carbohydrate (g) 18.23 12.9 Fiber (g) 0.95 1.2 Ash (g) 0.58 0.6 Minerals Calcium (mg) 9.00 – Iron (mg) 0.82 – Magnesium (mg) 22.00 – Phosphorus (mg) 29.00 – Potassium (mg) 320.00 – Sodium (mg) 22.00 – Vitamins Ascorbic acid (mg) 16.40 3.40 Thiamine (mg) 0.07 0.07 Ribofl avin (mg) 0.12 0.23 Niacin (mg) 1.52 0.79 Vitamin A 0 0 Seed/skin (%) 34 –

Marler, J.E., George, A.P., Nissen, R.J. and Andersen, P.J. (1994) Miscellaneous tropical fruits – annonas. In: Schaff er, B.C. and Andersen, P.C. (eds) Handbook of Environmental Physiology of Fruit Crops. Volume II: Subtropical and Tropical Crops. CRC Press, Boca Raton, Florida, pp. 200–206.

Pinto, A.C. (2002) Soursop. In: Crisóstomo, L.A. and Nuamov, A. (managing eds) and Johnston, A.E. (ed) Fertilizing for High Yield and Quality Tropical Fruits of Brazil. International Potash Institute Bulletin, IPI, Horgen, Switzerland, pp. 202–217.

REFERENCES

Alvarez-Garcia, L.A. (1949) Anthracnose of the Annonaceae in Puerto Rico. University of Puerto Rico, Journal of Agriculture 33, 27–43.

Avilán, R.L. (1975) Efecto de la omisión de los macronutrientes en el desarrollo y composición química de la guanábana (Annona muricata L.) cultivada en soluciones nutritivas. Agronomía Tropical (Maracay) 25, 73–79.

Broglio-Micheletti, S.M.F., Agra, A.G.S. de Melo., Barbosa, G.V.S. and Gomes, F.L. (2001) Controle de Cerconota anonella (Sepp.) (Lep.: Oecophoridae) e de Bephratelloides pomorum (Fab.) (Hym.: Eurytomidae) em frutos de graviola (Annona muricata L.). Revista Brasileira de Fruticultura 23, 722–725.

Clement, C.R., Mueller, C.H. and Chavez Flores, W.B. (1982) Recursos genéticos de espécies frutiferas nativas da Amazonía Brasileira. Acta Amazonica 12, 677–685. Donadio, L.C., Moro, F.V. and Servidone, A.A. (2002) Frutas Brasileiras. Editora Novos

Talentos, Jaboticabal, Sao Paulo, Brazil.

Duarte, O. (1997) Guanábana. Boletín de Divulgación, Escuela Agrícola Panamericana, El Zamorano, Honduras.

Escobar, W. and Sánchez, L.A. (1992) Guanábano. Manual de Asistencia Técnica No. 57. Sección Nacional de Frutícolas, Instituto Colombiano Agropecuario (ICA), Colombia.

George, A.P., Nissen, R.J. and Brown, B.I. (1987) The Custard Apple. Queensland Agricultural Journal 113, 287–297.

Hernández, M.C.L.V. and Nieto-Angel, D. (1997) Diagnostico Técnico y Comercial de la Guanábana en México. Memorias del Congreso Internacional de Anonáceas, Universidad Autonoma Chapingo (UAC), Chapingo, México.

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.

Laprode, S.C. (1991) Variación estacional de nutrimentos foliares em guanabana (Annona muricata L.). Revista Corbana 15, 6–10.

Manica, I. (2000) Frutas Nativas, Silvestres e Exoticas 1. Cinco Continentes Editora, Porto Alegre, Brasil.

Mansour, K.M. (1997) Current status of Annonaceae in Egypt. Mesfi n Newsletter 1, 5–10. Marler, J.E., George, A.P., Nissen, R.J. and Andersen, P.J. (1994) Miscellaneous

tropical fruits – annonas. In: Scheaff 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.

Morton, J.F. (1987) Fruits of Warm Climates. Creative Resource Systems Inc., Winterville, North Carolina, pp. 88–90.

Nakasone, H.Y. (1972) Production feasibility for soursop. Hawaii Farm Science 21, 10– 11.

Paull, R.E. (1982) Postharvest variation in composition of soursop (Annona muricata L.) fruit in relation to respiration and ethylene production. Journal of the American Society for Horticultural Science 107, 582–585.

Paull, R.E. (1983) Changes in organic acids, sugars, and headspace volatiles during fruit ripening of soursop (Annona muricata L.). Journal of the American Society for Horticultural Science 108, 931–934.

Pinto, A.C. de Q. and da Silva, E.M. (1996) Graviola Para Exportação, Aspectos Técnicos da Produção. Embrapa-SPI, Brasília.

Pinto, A.C. de Q., Cordeiro, M.C.R., de Andrade, S.R.M., Ferreira, F.R., Filgueiras, H.A. de C., Alves. R.E. and Kinpara, D.I. (2005) Annona species. International Centre for Underutilized Crops, University of Southampton, UK. Available from: http://www. icuc-iwmi.org/fi les/R7187_-_Annona%20monograph%202005.pdf. Accessed August 20, 2011.

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 Q190031. Queensland Department of Primary Industries, Brisbane, Australia.

SCUC (Southern Centre for Underutilized Crops) (2006) Annona: Annona cherimola, A. muricata, A. reticulata, A. senegalensis and A. squamosa. Field Manual for Extension Workers and Farmers. University of Southampton, Southampton, UK.

Silva, A.Q. and Silva, H. (1997) Nutrição e Adubação de Anonáceas. In: São José, A.R., Souza, I.V.B., Morais, O.M. and Rebouças, T.N.H. (eds.) Anonáceas, Produção e Mercado. Universidade Estadual do Sudoeste da Bahia, Vitória da Conquista, Bahia, pp. 118–137.

Silva, H.A., da Silva, A.Q., Cavalcante, A.T. and Malavolta, E. (1984) Composição mineral das folhas de algunas fruteiras do Nordeste. Anais do 7mo. Congresso Brasileiro de Fruticultura (Florianópolis), pp. 320–325.

Sousa, N.R. (2008) Rollinia mucosa Biribá. In: Janick, J. and Paull, R.E. (eds) Encyclopedia of Fruit and Nuts. CAB International, Wallingford, UK, pp. 68–70.

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.

Vargas, O., Alix, C., Lobo, A.D. (Authors), Duarte, O. and Sanchez, J. (Technical Reviewers). (1999) Frutales y Condimentarias del Trópico Húmedo. CURLA; PDBL; AFE/COHDEFOR; DICTA; SETCO; PROFORFITH, La Ceiba, Honduras.

Villachica, H., de Carvalho, J.E.U., Muller, C.H., Diaz, C. and Almanza, M. (1996) Anona (Rollinia mucosa (Jacq.) Baillón), In: Frutales y Hortalizas Promisorias de la Amazonía. Tratado de Cooperación Amazónica, Secretaría Pro-Tempore, Lima, Peru, pp. 20– 24.

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.

Worrell, D.B., Carrington, C.M.S. and Huber, D.J. (1994) Growth, maturation, and ripening of soursop (Annona muricata L.) fruit. Scientia Horticulturae 57, 7–15.

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.

© Paull and Duarte 2012. Tropical Fruits, 2nd Edition, Volume II 25 (R.E. Paull and O. Duarte)

B

READFRUIT

, J

ACKFRUIT

, C

HEMPEDAK

AND

M

ARANG

The family Moraceae includes the fi g and mulberry. The genus Artocarpus, which includes breadfruit, jackfruit, chempedak and marang, contains about 50 species with milky latex. Most species are native to Asia, and 15 produce edible starchy fruit that are frequently staples. The genus name comes from the Greek words ‘artos’ (bread) and ‘karpos’ (fruit). The three most important species are the more tropical breadfruit A. altilis (Parkinson) Fosberg (syn A. communis, Foster; A. incisus L.; Communis incisa), the jackfruit A. heterophyllus Lam. (syn A. integer [Thumb.] Merrill; A. integrifolius) and its close relative chempedak A. integrifolia L., (syn. A. polyphema Persoon; A. champeden [Lour.] Stokes).

Other Artocarpus species are also grown: A. odoratissimus (marang), A. camansi (breadnut) Blanco, A. lakoocha Roxb. (monkey jack) and A. mariannensis Trécul. (dugdug). Species with edible fruit that are not commercially grown, but are collected and consumed in their native range, include A. anisophyllus Miq., A. chama Buch-Ham., A. fulvicortex Jarrett, A. hypargyreus Hance, A. kemando Miq., A. lanceifolius Roxb. subsp. lanceifolius and clementis Merr., A. nitidus Trécul., A. rigidus Blume, A. sarawakensis Jarrett., A. sericicarpus Jarrett, A. styracifolius Pierre, A. tonkinensis, A. Chevalier and A. vrieseanus Miq. (Love, 2008).

BREADFRUIT

Introduction

Breadfruit originates from New Guinea and possibly the Moluccas, with numerous varieties spread throughout the islands of the Pacifi c. It has been distributed throughout the humid tropics since the late 1700s. The tree was the reason behind Captain Bligh’s voyage to Tahiti and the mutiny on The Bounty (Spary and White, 2004). In many regions, the seeded and

seedless cultivars have diff erent common names. Seeded breadfruits are called breadnut (English), kelur or kelor (Indo-Malaya) and kamansi or pakok (Philippines), while seedless are sukun (Indo-Malaya) and rimas (Philippines). Other names include arbre à pain (French), sake (Thai and Vietnamese), árbol del pan or panapen (Spanish), fruta pao (Portuguese) and ulu, uru, kuru, uto, mei, lemae and mos (Pacifi c islands).

Two closely related species that possibly contributed to breadfruit are breadnut A. camansi Blanco from New Guinea, the Indo-Malay region and possibly the Philippines; and dugdug A. mariannensis Trécul from western Micronesia. Breadnut is a wild ancestor of the breadfruit indigenous to the lowlands of New Guinea, where it grows in fl ooded riverbanks, secondary and primary growth forest, and freshwater swamps, and in cultivation. It may also be indigenous to the Moluccas and possibly the Philippines. Dugdug is morphologically very distinct from A. altilis and grows wild in Palau, Guam and the Northern Mariana Islands. Introgression between the two species has occurred in Micronesia and there are a number of hybrid varieties (Ragone, 1997).

Breadfruit is principally grown as a subsistence crop in most areas of the world, with Pacifi c and Caribbean islands being the major production areas. Fruit range from 0.2 to 4.5 kg, depending on the cultivar. Yields vary from as low as 50–150 to as many as 700 fruit/tree, with an estimated yield of 16–50 t/ha based on a density of 100 trees/ha. Canopy volume is a good measure of the potential yield.

Ecology

Soil

A variety of soils with suffi cient depth and good drainage are suitable. Soils with high levels of organic matter and fertility are recommended. On Pacifi c islands, breadfruit does grow on shallow coralline soils, demonstrating its considerable varietal adaptability.

Climate

Regular rainfalls of 1500–3000 mm/year and humidity of 70–90% are preferred. Rainfall is necessary for vegetative growth, fl owering and fruit growth, with a bimodal pattern preferred with a 3–6 month dry season. The tree is sensitive to chilling, with no growth at temperatures of 5°C or lower. The tree is well suited to hot, humid, tropical lowlands, with temperatures of up to 38°C and altitude below 1500 m. Best production takes place below 650 m in the tropics. Full sun is required, and no photoperiodic events have been noted.

General characteristics

Tree

This fast-growing evergreen tree can grow up to 30 m in humid and wet areas, and can live for as long as 90 years. The tree is partially deciduous under drought or during the dry part of a monsoon climate. The alternate and ovate leaves, which are 20–75 cm in length, are dark green with none to as many as 13 lobes (Fig. 2.1A). The trunk is straight, with thick branches terminating in branches of 10–20 cm in length with two large deciduous stipules enclosing the terminal bud. Root suckers begin bearing in 3–5 years and seedling plants in 8–10 years.

A

D B

C

Fig. 2.1. Breadfruit leaf (A), male (B) and female (C) fl owers and immature fruit (D).

Jackfruit and chempedak infl orescences are similar in shape. (From Nakasone and Paull, 1998, with permission from CAB International.)

Flowers

This monoecious species has the staminate (Fig. 2.1B) and pistillate infl orescence on a 4–15 cm peduncle in separate leaf axils. The drooping, spongy, club-shaped male (15–20 u 3–4 cm) infl orescence has minute fl owers, each with a single stamen. The globose pistillate infl orescence (6–10 cm) is covered with numerous tiny fl owers on a spongy axis. Each pistillate fl ower is reduced to a tubular calyx with a two-celled ovary, and a two-lobed stigma on a short style.

Pollination and fruit set

Rain encourages vegetative growth and fl owering. Some cultivars can fl ower throughout the year under the right environmental conditions. Cross-pollination is assured by the staminate infl orescences maturing before the pistillate. Following wind or insect pollination, fertilization occurs over 3–6 days in seeded cultivars. A high percentage (75%) of the fl orets are set, with the percentage being reduced in rainy weather. This reduction suggests that pollination is necessary to stimulate parthenocarpic growth. However, pollination is diffi cult as the rudimentary perianth acts as a physical barrier to pollination and argues against the fruit being parthenocarpic. Pollen sterility is also a factor contributing to reduced fertility and seed production.

Paclobutrazol, naphthalene acetic acid and ethephon inhibit vegetative growth but fail to stimulate fl owering. In the West Indies, methanol spray in the dry season has been found to enhance vegetative growth and bring about earlier and more profuse fl owering. Solar radiation signifi cantly infl uences the onset of fl owering and female infl orescence production. Fruit set is also related to tree width, with fewer fruit setting on trees with a greater width; this is possibly associated with uneven light interception, and suggests that tree management including pruning and plant spacing can impact fruit yield.

Fruit

The fruit develops from the entire infl orescence as the perianths of the individual fl owers attached to the central axis or core, fuse together and become fl eshy (Fig. 2.1D). The fruit is normally round to oblong, sometimes cylindrical and 10–30 cm in length. The thin, reticulated skin is pale green or yellow–green when the fruit is mature, turning yellow-brown when ripe. The core is surrounded by a pale-yellow or creamy white edible pulp (Fig. 2.2). Most cultivars are seedless, but the seeded wild types have 10–150 brown seeds of 2.5 cm in length.

Depending on the stage of maturity and cultivar, the core and the fl esh will exude a white viscous latex that discolors greenish or reddish-brown on exposure to air. The skin also exudes latex and dried, hardened drops are an indication of fruit maturity in some varieties. The fruit matures in 13–21 weeks from the time the pistillate infl orescence is fi rst detectable in the terminal leaf