From Plant
Resources of South-East Asia (PROSEA)
by R. E. Coronel
Taxon
Manilkara zapota (L.) P. van Royen
Protologue
Blumea 7: 410 (1953).
Family
SAPOTACEAE
Chromosome
Numbers
2n = 26
Synonyms
Achras zapota L. (1753), p.p., Pouteria mammosa (L.) Cronquist (1946), p.p. min., Nispero achras (Miller) Aubréville (1965), nom. inval.
Vernacular
Names
Sapodilla,
naseberry (En). Sapotillier (Fr). Indonesia: sawo manila, ciku
(Sundanese), sawo londo (Java). Malaysia: ciku. Philippines: chico.
Cambodia: lomut. Laos: lamud. Thailand: lamut, lamut-farang. Vietnam:
xabôchê, hông xiêm, tâ lu'c.
Origin and
Geographic Distribution
Sapodilla
is a native of Central America, Mexico and the West Indies. It is now
cultivated to a greater or lesser extent in the tropical lowlands of
both hemispheres. It is an important fruit all over South-East Asia.
Uses
Sapodilla is grown mainly for
its fruit which is predominantly eaten fresh. The fruits may also be
used in sherbets or ice cream or made into preserve, butter or jam. The
juice may be boiled into syrup or fermented into wine or vinegar.
Wild
and cultivated trees in America are tapped for their milky latex which
coagulates into chicle, the principal constituent of chewing gum before
the advent of synthetics. This gum is also used in the manufacture of
transmission belts, in dental surgery, and as a substitute for gutta
percha, a coagulum of the latex of Palaquium spp., also in the
Sapotaceae, which had many applications in industry before the advent
of plastics.
The wood is an excellent material for making
cabinets and furniture. The seeds are antipyretic. In Indonesia the
flowers are used as one of the ingredients in preparing a powder which
is rubbed on the body of a woman after childbirth. The tannin from the
bark is used to tan ship sails and fishing tackle; in Cambodia the
tannin is used to cure diarrhoea and fever.
Production and International Trade
Sapodilla
is popular in South-East Asia because the fruit is very sweet.
Statistics indicate that the region is the major producer of the fruit:
in 1987 Thailand produced 53 650 t with a total area of 18 950 ha; the
Philippines 11 900 t with 4780 ha, Peninsular Malaysia 15 000 t with
1000 ha; in Indonesia production during 1986 was estimated at 54 800 t.
The fruit is consumed almost entirely in the country of production and
international trade is negligible. In many areas it is available when
few other fruits are in season.
Properties
The sapodilla
fruit is rather dry and some cultivars have a gritty texture. About 84%
of the fruit is edible and contains, per 100 g: water 74 g, protein 0.5
g, fat 0.9 g, carbohydrates 24 g, fibre 3.0 g, ash 0.4 g, phosphorus 32
g, calcium 9 mg, iron 1 mg, sodium 5 mg, potassium 198 mg, vitamin A 85
IU, thiamine and riboflavin 0.01 mg, niacin 0.3 mg and vitamin C 26 mg.
The energy value is 400 kJ/100 g. The predominant organic acid in the
fruit is malic acid.
Description
Evergreen,
upright to spreading tree, 5—20(—30)m tall, all parts rich in white
gummy latex; trunk low-branched, bark rough, dark-brown, crown globose
or pyramidal, conforming to Aubréville's architectural model. Leaves
alternate, ovate-elliptic to oblong-lanceolate, 3.5—15 cm x 1.5—7 cm,
cuneate or obtusely acuminate at both ends, frequently emarginate,
entire, glabrescent, glossy dark green, midrib prominent below, lateral
nerves numerous, parallel; petiole 1—3.5 cm long. Flowers solitary in
upper leaf axils, usually pendulous, up to 1.5 cm in diameter,
brown-hairy outside; pedicel 1—2 cm long; calyx deeply 6-parted,
usually in two whorls, densely grey or brown tomentose outside; corolla
white, campanulate, 6 lobes about half as long as the tube; staminodes
6, petaloid; stamens 6; ovary 10—12-celled, villous; style subulate,
exserted from the flower. Fruit a pendulous berry, globose, ovoid or
ellipsoid, 3—8 cm x 3—6 cm, rounded or impressed at base, apex rounded
and crowned by the remnants of the style; skin thin, dull reddish to
yellow-brown, covered with a sandy brown scurf; flesh juicy, soft,
yellow to red-brown, sweet. Seeds 0—6(—12), oblong, 2 cm long, brown or
black, compressed laterally, hilum distinct.
Growth and Development
The
seeds germinate about 30 days after sowing without any treatment and
exhibit an epigeal type of germination. The seedlings grow very slowly,
producing a central stem which dominates the whorls of laterals in
trees with an upright habit; the spreading habit is achieved by more
prominent sympodial extension of the laterals. In an equable climate
some extending shoots can be found at any time, but trees relieved from
stress may seem to produce a general flush. Seedling trees start to
flower 6—10 or more years after planting; grafted trees in 4—6 years
and marcotted trees in 3—4 years. Flowers are produced in the leaf
axils near the tip of young or mature shoots. These shoot tips have
greatly shortened internodes, so that the flowers appear to be borne in
clusters. Flowering may take place throughout the year but the peak of
flowering in the Philippines is April to June, that is early in the
rainy season.
Observation of 2 cultivars in the Philippines
showed that flower buds reach anthesis 45—60 days after emergence. The
stigma is receptive between one day before and 3 days after flower
opening; on the day of opening it is sticky with stigmatic fluid.
Self-fertile cultivars produce much pollen, which is viable.
Cross-pollination by insects, e.g. bees, is recommended and is
necessary for low-yield cultivars, most of which produce little pollen,
which is defective. Fruit growth as observed in India proceeds in 3
distinct stages: in the first 16 weeks diameter exceeds length; after a
transitory period of 4 weeks the fruit assumes its characteristic
oblong-ovoid shape and takes another 9 weeks to ripen. The fruits take
about 6—8.5 months to mature so that in the Philippines the main
harvest season is from December to February. In Thailand the fruit is
more seasonal and abundant from September to December.
Other Botanical Information
Numerous cultivars exist, often bearing local names; in many cases names in different localities are presumably synonyms.
In
Indonesia 2 groups of cultivars are distinguished: Sawo manila with
ovoid fruit, including 'Sawo Betawi' and 'Sawo Kulan' and Sawo apel
with globose fruits, e.g. 'Sawo Apel Benar' and 'Sawo Apel Lilin'.
In
the Philippines the small-fruited, prolific 'Pineras' is most common.
'Ponderosa' has large fruit of excellent quality but it does not soften
uniformly after harvest and trees require cross-pollination for good
yield. Other cultivars are 'Sao Manila' and 'Gonzalez'. Well-known Thai
cultivars are the small-fruited 'Krasuey', the fairly large-fruited
'Kai Hahn' and the medium sized, globose 'Makok'. Popular cultivars in
Malaysia are 'Santong', 'C 54' and 'C 58'. In Queensland, Australia,
cultivars from various countries have been evaluated; the most
promising cultivars are 'Kai Hahn', 'Makok', 'C 58', 'Tropical', 'BKD
110' and 'Sao Manila'.
Ecology
Sapodilla
is a very adaptable species. It thrives in the tropics, but is found in
large numbers at elevations up to 2500 m in Ecuador and also in the
subtropics (Israel); mature trees are not greatly damaged by a few
degrees of frost. Sapodilla is very drought-resistant, doing well in
the taxing monsoon climates of India.
With its tough branches
the tree tolerates strong winds and salt sprays close to the seashore.
However, growth and fruit quality are impaired in extreme environments;
the tree thrives in warm, moist tropical lowlands, usually below 600 m
in South-East Asia. The best soil for sapodilla is a rich, well
drained, sandy loam, but few soils are unsuitable and sapodilla comes
second after the date palm in the category of fruit trees with high
tolerance of saline soils.
Propagation and planting
Cultivars
are propagated either by grafting or marcotting. The seeds for
rootstocks are sown in a sandy seedbed, about 2 cm apart and at a depth
of about 1 cm. The seeds germinate in about 30 days, fresh seed giving
up to about 80% germination. Seeds can be kept for several months but
it is best to sow them immediately after collection. After a few months
the seedlings are transplanted into polybags. They grow very slowly;
even if spurred on by nitrogen applications, it takes 2—3 years before
the rootstocks are ready for grafting.
Other species of Manilkara
Adans. have been tried as rootstocks, partly to find faster growing
seedlings. Manilkara kauki (L.) Dubard did well in Indonesia and India
and is being tried in the Philippines. However, in India Manilkara
hexandra (Roxb.) Dubard proved to be the best rootstock, even after 40
years, provided only the more vigorous seedlings were grafted, there
being much variation in vigour. Some species of Madhuca J.F. Gmelin,
Palaquium Blanco and Sideroxylon L. are also graft-compatible with
sapodilla. Inarching is the traditional grafting method, giving as much
as 95—100% success. However it is a rather laborious method. In the
Philippines it has been replaced by cleft or wedge grafting. Sapodilla
can be grafted any month of the year, but best results are obtained
during the cooler and drier months (November—February in the
Philippines).
Scions are cut from quiescent terminal shoots with buds
ready to sprout. Fruiting twigs are better than non-fruiting twigs.
Cleft grafting gives 80—90% success.
Marcotting is best done during
the rainy season. The branches to be used should be more or less
upright and have a diameter of about 1 cm. Coconut coir is one of the
common rooting materials used. Treating the girdled stem with a root
hormone is beneficial. Complete rooting is achieved in 4—12 months
depending on the size of the branch and on the cultivar used. Success
in marcotting is 60% or more, the smaller branches generally showing
the highest percentage take. Mist propagation using leafy stem cuttings
treated with a root-promoting substance has been successful. The
suggested tree spacing in the orchard is 6—10 m. Planting is best done
at the onset of the rainy season.
Husbandry
Newly
planted trees need to be watered during dry periods to improve
establishment. Moreover, the trees respond by extra growth and come
into bearing more quickly. Although the trees are very
drought-resistant, flowers and fruitlets are shed under moisture
stress; hence in dry climates bearing trees also benefit from
irrigation.
The tree architecture with a central leader and
whorls of laterals extending sympodially, calls for little pruning, the
more so since the flowers are borne near the shoot tip. However, in
clonally propagated trees the architecture is not so clearly expressed.
In cultivars with upright growth the central leader may be headed back
in the formative years to promote lateral growth. In cultivars with a
cluttered habit pseudo-central-leaders should be removed and some
thinning of weak and interlacing branches is recommended as the trees
grow older. Also the lower whorl of branches is removed as it sags
towards the ground.
In experiments in India the response of both
growth and fruiting to nitrogen was quite convincing. Mature trees need
1.5 kg N or more per year, recommended doses of P2O5 and K2O
are about 0.5 kg per tree. Fertilizer or manure is applied at the onset
of the rainy season, in time to support the increased extension growth
and flowering brought on by the rains, and well before the end of the
rainy season to sustain fruit growth. In this way fertilizing may
further concentrate the crop in a certain period. Fertilizer is applied
in a ring under the dripline of the tree canopy.
Diseases and Pests
There are no serious diseases of the sapodilla. The pink disease (Corticium salmonicolor) is a canker which kills affected branches. In India, a leaf spot disease (Phaeophleospora indica) has been reported.
Some insect pests may inflict serious damage to the sapodilla trees. The maggots of the oriental fruit fly (Dacus dorsalis) feed on the flesh of ripe fruit making it unfit for consumption. The larvae of the phycitid fruit borer (Alophia sp.) attack the fruits at all stages of development. The larvae of the gelechiid moth (Eustalodes anthivora) feed on the flowers causing them to drop. The twig-borer (Niponoclea albata and N. capito)
larvae tunnel into the twigs and pupate inside, whereas the adult
beetles girdle the branches. Mealy bugs and aphids feed on the leaves,
young shoots, flowers and young fruits. Scale insects cluster around
the twigs and branches and along the leaf midribs, causing leaf drop
and twig dieback.
Harvesting
Some
fruit may be ripening on the tree throughout the year, but generally
there are one or two major harvest peaks because of concentrated
blossoming, or because viable pollen is produced during certain
periods. The fruit is climacteric and is picked when mature but still
firm; it needs a few days to soften and become edible. The fruits are
considered mature when the skin colour turns from green to
yellowish-brown, the scurfy bloom on the skin comes off easily and the
latex flow is minimal when the fruit is detached. This change is not
easily seen, however, because the fruit surface is covered with a brown
powdery material. Therefore the surface of a few fruits is rubbed with
the thumb to remove the bloom and to observe the skin colour; as a
final test these fruits may be detached. Mature fruits are picked
without the stalk. A white latex exudes from the stalk, and the
practice in the Philippines is to put the fruits in a container with
water and allow them to 'bleed'. Bleeding is stimulated by scraping the
stalk end with the thumb nail or with a sharp object. If this is not
done the latex remains inside the fruit and coagulates there. The
fruits are scrubbed with a piece of cloth to remove the bloom and
allowed to dry by placing them with their stalk ends down.
Yield
There
are few records of actual yields. In India, a norm for annual fruit
number for trees of 7 years and older is to multiply tree age by 100,
2500 fruits being considered the maximum. Although the average yields
calculated on the basis of area and production are low (except for
Peninsular Malaysia), sapodilla is certainly not a reluctant bearer.
Annual yields per ha of 20—30 t have been reported in Florida, 20—25 t
in the Philippines and 20—80 t in India.
Handling After Harvest
The
fruits are usually graded and marketed immediately after harvest. They
ripen in 3—7 days. The fruits can be stored at low temperature to
prolong their shelf life. Unripe fruits stored at 15°C can be kept in
good condition for about 17 days; at lower temperatures unripe fruits
stored for more than 10 days do not ripen normally. Ripe fruits stored
at 0°C remain in good condition for 12—13 days.
Genetic Resources
Seedling
trees exhibit much variation in plant and fruit characters. In the
Philippines, for example, the introduction of new cultivars and the
planting of their seedlings has led to wide variability in the
sapodilla population. Moreover, many seedlings never bear fruit, pollen
sterility being quite common in seedling populations. In recent years
germplasm has been collected by the Institute of Plant Breeding in Los
Baños, the Philippines; Australia (Queensland), India, Cuba, Brazil,
Costa Rica, the United States (Florida, Puerto Rico, Hawaii) and some
other countries also maintain sapodilla germplasm collections.
Breeding
Cultivars
result from clonal propagation of selected seedling trees. The major
objectives in varietal improvement are large fruit size, good eating
quality and seedless fruits. Controlled hybridization started in India
in the 1950s, but this has not yet resulted in the introduction of new
cultivars. Only a few parents (e.g. 'Prolific' from Florida) produce
seedling offspring with viable pollen, bearing regularly.
Prospects
The
sapodilla is a very popular fruit in South-East Asia and other tropical
countries. It would seem that supplies do not fully meet domestic
demand. Trees are sufficiently fruitful and manageable to be grown in
orchards. The factors that largely determine the scope for expansion of
commercial production are shortening of the nursery period, better
insight into pollen viability and the compatibility of cultivars, as
well as development of growing techniques to shift the main flowering
and harvesting seasons.
Literature
Clarke, F.F.G., 1954. Eustalodes anthivora (Gelechiidae, Lepidoptera), a new pest of Achras zapota in the Philippines. The Philippine Agriculturists 37: 450—454.
Coronel, R.E., 1966. That chico called Ponderosa. Agriculture at Los Baños 5: 1—3.
De
Peralta, E. & de la Cruz, E.J., 1954. Preliminary study on the
vegetative propagation of the chico. Araneta Journal of Agriculture 2:
25—32.
Gonzalez, L.G. & Fabella, E.L., 1952. Intergeneric graft-affinity of the chico. The Philippine Agriculturists 35: 402—407.
Gonzalez,
L.G. & Feliciano. Jr., P.A., 1953. The blooming and fruiting habits
of the Ponderosa chico. The Philippine Agriculturists 37: 384—398.
Moncur,
W.M., 1988. Floral development of tropical and subtropical fruit and
nut species. An atlas of scanning election micrographs. Natural
Resources Series No 8. Division Water and Land Resources, CSIRO,
Melbourne. pp. 171—174.
Moore, H.E. & Stearn, W.T., 1967. The identity of Achras zapota L. and the names for the sapodilla and the sapote. Taxon 16: 382—395.
Schroeder,
C.A., 1958. The origin, spread and improvement of the avocado,
sapodilla and papaya. Indian Journal of Horticulture 15: 116—128.
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