Fruit Facts from
the
California Rare Fruit Growers, Inc.
Jackfruit
Artocarpus heterophyllus
Lam.
Moraceae
Common
Names: Jackfruit, Jakfruit, Jaca, Nangka.
Related
Species: Breadfruit (Artocarpus
altilis), Breadnut (A.
altilis 'Seminifera'), Champedak (A. integer),
Lakoocha (A. lakoocha),
Marang (A. odoratissimus).
Distant
affinity: Figs (Ficus
spp.), Mulberries (Morus
spp.), African Breadfruit (Treculia
african).
Origin: The
jackfruit is believed indigenous to the rain forests of the Western
Ghats of India. It spread early on to other
parts of India, southeast Asia, the East Indies and ultimately the
Philippines. It is often planted in central and eastern Africa and is
fairly popular in Brazil and Surinam.
Adaptation:
Jackfruit is adapted to humid tropical and near-tropical climates.
Mature trees have survived temperatures of about 27° F in southern
Florida, but these were frozen to large limbs. Young trees are likely
to be killed at temperatures below 32° F. Unlike its relative, the
breadfruit, the jackfruit is not injured by cool weather several
degrees above freezing. There are only a dozen or so bearing jackfruit
trees today in southern Florida, and these are valued mainly as
curiosities. There are also several trees planted in the Asian exhibit
at the San Diego Zoo. What they will do or how high they will grow
remains a question. The tree is too large to make a suitable
container-grown plant.
Description
Growth Habit:
The jackfruit tree is handsome and stately. In the tropics it grows to
an enormous size, like a large eastern oak. In California it is very
doubtful that it would ever approach this size. All parts contain a
sticky, white latex.
Foliage:
The leaves are oblong, oval, or elliptic in form, 4 to 6 inches in
length, leathery, glossy, and deep green in color. Juvenile leaves are
lobed.
Flowers:
Male and
female flowers are borne in separate flower-heads. Male flower-heads
are on new wood among the leaves or above the female. They are swollen,
oblong, from an inch to four inches long and up to an inch wide at the
widest part. They are pale green at first, then darken. When mature the
head is covered with yellow pollen that falls rapidly after flowering.
The female heads appear on short, stout twigs that emerge from the
trunk and large branches, or even from the soil-covered base of very
old trees. They look like the male heads but without pollen, and soon
begins to swell. The stalks of both male and female flower-heads are
encircled by a small green ring.
Fruit:
Jackfruit is the largest tree-borne fruit in the world, reaching 80
pounds in weight and up to 36 inches long and 20 inches in diameter.
The exterior of the compound fruit is green or yellow when ripe. The
interior consists of large edible bulbs of yellow, banana-flavored
flesh that encloses a smooth, oval, light-brown seed. The seed is 3/4
to 1-1/2 inches long and 1/2 to 3/4 inches thick and is white and crisp
within. There may be 100 or up to 500 seeds in a single fruit, which
are viable for no more than three or four days. When fully ripe, the
unopened jackfruit emits a strong disagreeable odor, resembling that of
decayed onions, while the pulp of the opened fruit smells of pineapple
and banana.
There are two main varieties. In one, the fruits
have small, fibrous, soft, mushy, but very sweet carpels with a texture
somewhat akin to a raw oysters. The other variety is crisp and almost
crunchy though not quite as sweet. This form is the more important
commercially and is more palatable to western tastes.
Culture
Location:
The jackfruit tree should have a well-drained, frost-free location that
is sunny and warm.
Soil:
The jackfruit flourishes in rich, deep soil of medium or open texture.
Planting on top of an old compost heap would be ideal. The faster one
can force a tropical plant to grow, the better the chance of keeping it
alive. The tree needs the best drainage and cannot tolerate "wet feet".
Irrigation:
The tree will not tolerate drought. Water frequently during warm months
and warm periods in cooler months. Less water is necessary during
colder weather.
Fertilization:
The jackfruit's requirements are not known, but frequent, weak
solutions of all-purpose fertilizer will speed the plant's growth
without causing burn. In the regions where it is commonly grown, it
succeeds without much care from man, the sole necessity being abundant
moisture.
Frost
protection:
Although mature jackfruit trees will take several degrees of frost, it
is prudent to provide young plants with overhead protection if possible
and plant them on the south side of a wall or building. Small plants
should be given complete protection with a covering on cold nights and
even a light bulb if possible.
Propagation: Propagation
is usually by seeds, which can be kept no longer than a month before
planting. Germination requires 3 to 8 weeks. The seedlings should be
moved when no more than 4 leaves have appeared. A more advanced
seedling, with its long and delicate tap root is very difficult to
transplant successfully. Cutting-grown plants and grafted seedlings are
possible. Air-layering is common in India.
Pruning:
Little or no pruning is required other than to remove any dead branches
from the interior of the tree, so that sufficient light is obtained for
the developing fruit.
Pests and
diseases:
A variety of pests and diseases afflict the jackfruit tree and fruit
regions where it is commonly grown. In California the white fly is a
minor pest.
Harvest:
Jackfruits mature 3 to 8 months from flowering. When mature, there is
usually a change of fruit color from light green to yellow-brown.
Spines, closely spaced, yield to moderate pressure, and there is a
dull, hollow sound when the fruit is tapped. After ripening, they turn
brown and deteriorate rather quickly. Cold storage trials indicate that
ripe fruits can be kept for 3 to 6 weeks at 52° to 55° F and
relative humidity of 85% to 95%. Immature fruit is boiled, fried, or
roasted. Chunks are cooked in lightly salted water until tender and
then served. The only handicap is copious gummy latex which accumulates
on utensils and hands unless they are first rubbed with cooking oil.
The seeds can also be boiled or roasted and eaten similar to chestnuts.
In Southeast Asia dried slices of unripe jackfruit are sold in the
markets. The ripe bulbs, fermented and then distilled, produce a potent
liquor.
Cultivars
In
Malaysia and India there are named types of fruit. One that has caused
a lot of interest is Singapore, or Ceylon, a remarkable yearly bearer
producing fruit in 18 months to 2-1/2 years from transplanting. The
fruit is of medium size with small, fibrous carpels which are very
sweet. It was introduced into India from Ceylon and planted extensively
in 1949. Other excellent varieties are Safeda, Khaja, Bhusila,
Bhadaiyan and Handia. In Australia, some of the varieties are: Galaxy,
Fitzroy, Nahen, Cheenax, Kapa, Mutton, and Varikkha. None of these
appear to be available in the US at this time.
Further Reading
Morton, Julia F. Fruits of Warm Climates. Creative Resources Systems,
Inc. 1987. pp. 58-63.
Popenoe, Wilson. Manual Of Tropical And Subtropical Fruits. Hafner
Press. 1974. Facsimile of the 1920 edition. pp. 414-419
Tankard, Glenn. Tropical Fruit: an Australian Guide to Growing and
Using Exotic Fruits. Viking O'Neil. 1987. pp. 52-53.
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© Copyright 1996-2001, California Rare Fruit Growers, Inc.
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