The jackfruit, Artocarpus heterophyllus Lam. (syns. A. integrifolius Auct. NOT L. f.; A integrifolia L. f.; A. integra Merr.; Rademachia integra Thunb. ), of the family Moraceae, is also called jak-fruit, jak, jaca, and, in Malaysia and the Philippines, nangka; in Thailand, khanun; in Cambodia, khnor; in Laos, mak mi or may mi; in Vietnam, mit. It is an excellent example of a food prized in some areas of the world and allowed to go to waste in others. O.W. Barrett wrote in 1928: “;The jaks . . . are such large and interesting fruits and the trees so well-behaved that it is difficult to explain the general lack of knowledge concerning them.”
The tree is handsome and stately, 30 to 70 ft (9-21 m) tall, with evergreen, alternate, glossy, somewhat leathery leaves to 9 in (22.5 cm) long, oval on mature wood, sometimes oblong or deeply lobed on young shoots. All parts contain a sticky, white latex. Short, stout flowering twigs emerge from the trunk and large branches, or even from the soil-covered base of very old trees.
The tree is monoecious: tiny male flowers are borne in oblong clusters 2 to 4 in (5-10 cm) in length; the female flower clusters are elliptic or rounded. Largest of all tree-borne fruits, the jackfruit may be 8 in to 3 ft (20-90 cm) long and 6 to 20 in (15-50 cm) wide, and the weight ranges from 10 to 60 or even as much as 110 lbs (4.5-20 or 50 kg). The “rind’ or exterior of the compound or aggregate fruit is green or yellow when ripe and composed of numerous hard, cone-like points attached to a thick and rubbery, pale yellow or whitish wall. The interior consists of large “bulbs” (fully developed perianths) of yellow, banana-flavored flesh, massed among narrow ribbons of thin, tough undeveloped perianths (or perigones), and a central, pithy core. Each bulb encloses a smooth, oval, light-brown “seed” (endocarp) covered by a thin white membrane (exocarp). The seed is 3/4 to 1 1/2 in (2-4 cm) long and 1/2 to 3/4 in (1.25-2 cm) thick and is white and crisp within. There may be 100 or up to 500 seeds in a single fruit. 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.
((Origin and Distribution))
No one knows the jackfruit’s place of origin but it is believed indigenous to the rainforests of the Western Ghats. It is cultivated at low elevations throughout India, Burma, Ceylon, southern China, Malaya, and the East Indies. It is common in the Philippines, both cultivated and naturalized. It is grown to a limited extent in Queensland and Mauritius. In Africa, it is often planted in Kenya, Uganda and former Zanzibar. Though planted in Hawaii prior to 1888, it is still rare there and in other Pactfic islands, as it is in most of tropical America and the West Indies. It was introduced into northern Brazil in the mid-19th Century and is more popular there and in Surinam than elsewhere in the New World. In 1782, plants from a captured French ship destined for Martinique were taken to Jamaica where the tree is now common, and about 100 years later, the jackfruit made its appearance in Florida, presumably imported by the Reasoner’s Nursery from Ceylon. The United States Department of Agriculture’s Report on the Conditions of Tropical and Semitropical Fruits in the United States in 1887 states: “There are but few specimens in the State. Mr. Bidwell, at Orlando, has a healthy young tree, which was killed back to the ground, however, by the freeze of 1886. ” There are today less than a dozen bearing jackfruit trees in South Florida and these are valued mainly as curiosities. Many seeds have been planted over the years but few seedlings have survived, though the jackfruit is hardier than its close relative, the breadfruit (q.v.).
In South India, the jackfruit is a popular food ranking next to the mango and banana in total annual production. There are more than 100,000 trees in backyards and grown for shade in betelnut, coffee, pepper and cardamom plantations. The total area planted to jackfruit in all India is calculated at 14,826 acres (26,000 ha). Government horticulturists promote the planting of jackfruit trees along highways, waterways and railroads to add to the country’s food supply. There are over 11,000 acres (4,452 ha) planted to jack fruit in Ceylon, mainly for timber, with the fruit a much-appreciated by-product. The tree is commonly cultivated throughout Thailand for its fruit. Away from the Far East, the jackfruit has never gained the acceptance accorded the breadfruit (except in settlements of people of East Indian origin). This is due largely to the odor of the ripe fruit and to traditional preference for the breadfruit.
In South India, jackfruits are classified as of two general types:
1) Koozha chakka, the fruits of which have small, fibrous, soft, mushy, but very sweet carpels;
2) Koozha pazham, more important commercially, with crisp carpers of high quality known as Varika. These types are apparently known in different areas by other names such as Barka, or Berka (soft, sweet and broken open with the hands), and Kapa or Kapiya (crisp and cut open with a knife). The equivalent types are known as Kha-nun nang (firm; best) and Kha-nun lamoud (soft) in Thailand; and as Vela (soft) and Varaka, or Waraka (firm) in Ceylon. The Peniwaraka, or honey jak, has sweet pulp, and some have claimed it the best of all. The Kuruwaraka has small, rounded fruits. Dr. David Fairchild, writing of the honey jak in Ceylon, describes the rind as dark-green in contrast to the golden yellow pulp when cut open for eating, but the fruits of his own tree in Coconut Grove and those of the Matheson tree which he maintained were honey jaks are definitely yellow when ripe. The Vela type predominates in the West Indies.
Firminger described two types:
the Khuja (green, hard and smooth, with juicy pulp and small seeds);
the Ghila (rough, soft, with thin pulp, not very juicy, and large seeds).
Dutta says Khujja, or Karcha, has pale-brown or occcasionally pale-green rind, and pulp as hard as an apple; Ghila, or Ghula, is usually light-green, occasionally brownish, and has soft pulp, sweet or acidulously sweet. He describes 8 varieties, only one with a name. This is Hazari; similar to Rudrakshi; which has a relatively smooth rind and flesh of inferior quality. The ‘Singapore’, or ‘Ceylon’, jack, a remarkably early bearer producing fruit in 18 months to 2 1/2 years from transplanting, was introduced into India from Ceylon and planted extensively in 1949. The fruit is of medium size with small, fibrous carpers which are very sweet. In addition to the summer crop (June and July), there is a second crop from October to December. In 1961, the Horticultural Research Institute at Saharanpur, India, reported the acquisition of air-layered plants of the excellent varieties, ‘Safeda’, ‘Khaja’, ‘Bhusila’, ‘Bhadaiyan’ and ‘Handia’ and others. The Fruit Experimental Station at Burliar, established a collection of 54 jackfruit clones from all producing countries, and ultimately selected ‘T Nagar Jack’ as the best in quality and yield. The Fruit Experimental Station at Kallar, began breeding work in 1952 with a view to developing short, compact, many-branched trees, precocious and productive, bearing large, yellow, high quality fruits, 1/2 in the main season, 1/2 late. ‘Singapore Jack’ was chosen as the female parent because of its early and late crops; and, as the male parent, ‘Velipala’, a local selection from the forest having large fruits with large carpers of superior quality, and borne regularly in the main summer season. After 25 years of testing, one hybrid was rated as outstanding for precocity, fruit size, off-season as well as main season production, and yield excelling its parents. It had not been named when reported on by Chellappan and Roche in 1982.
In Assam, nurserymen have given names such as ‘Mammoth’, ‘Everbearer’, and ‘Rose-scented’ to preferred types. Pollination Horticulturists in Madras have found that hand-pollination produces fruits with more of the fully developed bulbs than does normal wind-pollination.
The jackfruit is adapted only to humid tropical and near-tropical climates. It is sensitive to frost in its early life and cannot tolerate drought. If rainfall is deficient, the tree must be irrigated. In India, it thrives in the Himalayan foothills and from sea-level to an altitude of 5,000 ft (1,500 m) in the south. It is stated that jackfruits grown above 4,000 ft (1,200 m) are of poor quality and usable only for cooking. The tree ascends to about 800 ft (244 m) in Kwangtung, China.
The jackfruit tree flourishes in rich, deep soil of medium or open texture, sometimes on deep gravelly or laterite soil. It will grow, but more slowly and not as tall in shallow limestone. In India, they say that the tree grows tall and thin on sand, short and thick on stony land. It cannot tolerate “wet feet”. If the roots touch water, the tree will not bear fruit or may die.
Propagation is usually by seeds which can be kept no longer than a month before planting. Germination requires 3 to 8 weeks but is expedited by soaking seeds in water for 24 hours.
Soaking in a 10% solution of gibberellic acid results in 100% germination. The seeds may be sown in situ or may be nursery-germinated and 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. Budding and grafting attempts have often been unsuccessful, though Ochse considers the modified Forkert method of budding feasible. Either jackfruit or champedak (q.v.) seedlings may serve as rootstocks and the grafting may be done at any time of year. Inarching has been practiced and advocated but presents the same problem of transplanting after separation from the scion parent. To avoid this and yet achieve consistently early bearing of fruits of known quality, air-layers produced with the aid of growth promoting hormones are being distributed in India.
In Florida cuttings of young wood have been rooted under mist. At Calcutta University, cuttings have been successfully rooted only with forced and etiolated shoots treated with indole butyric acid (preferably at 5,000 mg/l) and kept under mist. Tissue culture experiments have been conducted at the Indian Institute of Horticultural Research, Bangalore.
Soaking one-month-old seedlings in a gibberellic acid solution (25-200 ppm) enhances shoot growth. Gibberellic acid spray and paste increase root growth. In plantations, the trees are set 30 to 40 ft (9-12 m) apart. Young plantings require protection from sunscald and from grazing animals, hares, deer, etc. Seeds in the field may be eaten by rats.
Firminger describes the quaint practice of raising a young seedling in a 3 to 4 ft (0.9-1.2 m) bamboo tube, then bending over and coiling the pliant stem beneath the soil, with only the tip showing.
In 5 years, such a plant is said to produce large and fine fruits on the spiral underground. In Travancore, the whole fruit is buried, the many seedlings which spring up are bound together with straw and they gradually fuse into one tree which bears in 6 to 7 years. Seedlings may ordinarily take 4 to 14 years to come into bearing, though certain precocious cultivars may begin to bear in 2 1/2 to 3 1/2 years. The jackfruit is a fairly rapid grower, reaching 58 ft (17.5 m) in height and 28 in (70 cm) around the trunk in 20 years in Ceylon. It is said to live as long as 100 years. However, productivity declines with age.
In Thailand, it is recommended that alternate rows be planted every 10 years so that 20-year-old trees may be routinely removed from the plantation and replaced by a new generation. Little attention has been given to the tree’s fertilizer requirements. Severe symptoms of manganese deficiency have been observed in India. After harvesting, the fruiting twigs may be cut back to the trunk or branch to induce flowering the next season.
In the Cachar district of Assam, production of female flowers is said to be stimulated by slashing the tree with a hatchet, the shoots emerging from the wounds; and branches are lopped every 3 to 4 years to maintain fruitfulness. On the other hand, studies at the University of Kalyani, West Bengal, showed that neither scoring nor pruning of shoots increases fruit set and that ringing enhances fruit set only the first year, production declining in the second year.
In Asia, jackfruits ripen principally from March to June, April to September, or June to August, depending on the climatic region, with some off-season crops from September to December, or a few fruits at other times of the year. In the West Indies, I have seen many ripening in June; in Florida, the season is late summer and fall.
- HARVESTING & YIELD
Fruits mature 3 to 8 months from flowering. In Jamaica, an “X” is sometimes cut in the apex of the fruit to speed ripening and improve flavor.
In India, a good yield is 150 large fruits per tree annually, though some trees bear as many as 250 and a fully mature tree may produce 500, these probably of medium or small size.
Jackfruits turn brown and deteriorate quickly after ripening. Cold storage trials indicate that ripe fruits can be kept for 3 to 6 weeks at 52Â° to 55Â°F (11.11Â°-12.78Â°C) and relative humidity of 85 to 95%.
- PESTS & DISEASES
Principal insect pests in India are the shoot-borer caterpillar, Diaphania caesalis; mealybugs. Nipaecoccus viridis, Pseudococcus corymbatus, and Ferrisia virgata, the spittle bug, Cosmoscarta relata, and jack scale, Ceroplastes rubina. The most destructive and widespread bark borers are Indarbela tetraonis and Batocera rufomaculata. Other major pests are the stem and fruit borer, Margaronia caecalis, and the brown bud-weevil, Ochyromera artocarpio.
In southern China, the larvae of the longicorn beetles, including Apriona germarri; Pterolophia discalis, Xenolea tomenlosa asiatica, and Olenecamptus bilobus seriously damage the fruit stem. The caterpillar of the leaf webbers, Perina nuda and Diaphania bivitralis, is a minor problem, as are aphids, Greenidea artocarpi andToxoptera aurantii; and thrips, Pseudodendrothrips dwivarna.
Diseases of importance include pink disease, Pelliculana (Corticium) salmonicolor, stem rot, fruit rot and male inflorescence rot caused by Rhizopus artocarpi; and leafspot due to Phomopsis artocarpina, Colletotrichum lagenarium, Septoria artocarpi, and other fungi. Gray blight, Pestalotia elasticola, charcoal rot, Ustilana zonata, collar rot, Rosellinia arcuata, and rust, Uredo artocarpi, occur on jackfruit in some regions. The fruits may be covered with paper sacks when very young to protect them from pests and diseases. Burkill says the bags encourage ants to swarm over the fruit and guard it from its enemies.