Jackfruit (Artocarpus heterophyllus) is a congener of (i.e., member of the same genus as) Breadfruit (Artocarpus altilis), as well as a number of other culturally and economically important trees (e.g., A. mariannensis, A. camansi, A. integer, A. lakoocha, A. odoratissima, and A. lingnanensis) (Elevitch and Manner 2006).
The jackfruit, the largest of all cultivated fruits, is oblong to cylindrical and typically 30 to 40 cm in length, although it can sometimes reach 90 cm. Jackfruits usually weigh 4.5 to 30 kg (commonly 9 to 18 kg), with a maximum reported weight of 50 kg. The heavy fruits are borne primarily on the trunk and on the interior parts of main branches. Jackfruit is a multiple aggregate fruit (i.e., it is formed by the fusion of multiple flowers in an inflorescence). It has a green to yellow-green exterior rind. The hard outer covering is derived from the enlarged female flowers. The whitish fibrous pulp within contains many seeds (as many as 500 per fruit). The acid to sweetish (when ripe) banana-flavored flesh (aril) surrounds each seed. The heavy fruit is held together by a central fibrous core. In the Northern Hemisphere, the fruiting season is mainly late spring to early fall (March to September), especially the summer. A few fruits mature in winter or early spring. The succulent, aromatic, and flavorful fruit is eaten fresh, cooked as a starchy vegetable, or preserved (e.g., salted like a pickle). The nutritious seeds are boiled or roasted and eaten like chestnuts, added to flour for baking, or added as ingredients to cooked dishes. (Little and Wadsworth 1964; Seddon and Lennox 1980; Vaughan and Geissler 1997; Elevitch and Manner 2006)
Male and female flowers are borne on the same individual trees (i.e., Jackfruit is monoecious), but in separate enlarged, fleshy flower clusters that sprout from older branches and from the trunk. The yellowish green fleshy club-shaped male flower spike is borne on a stalk 5 to 10 cm long. Male spikes are found on younger branches above female spikes. The numerous tiny flowers, each with a 2-lobed calyx and a single stamen, are pale green when young but darken with age. The similarly numerous but slightly larger female flowers are borne in an elliptic or rounded cluster. Each female flower has a tubular hairy calyx, a pistil with a 1-celled 1-ovuled ovary, a slender style, and a broader yellow stigma. Jackfruit flowers are reportedly pollinated by both insects and wind, with a high rate of cross pollination. The simple, alternately arranged leaves (10 to 15 cm long and 5 to 8 cm wide) are glossy dark green, thick, and leathery. The petioles (leaf stalks) are stout and 1 to 2 cm long. Leaf blades have entire margins and may be oblong to oval or narrow. Leaves are often deeply lobed on young plants and shoots. The cut bark of Jackfruit trees produces a milky juice. (Little and Wadsworth 1964; Elevitch and Manner 2006)
Jackfruit trees typically reach a height of 8 to 25 m and a canopy diameter of 3.5 to 6.7 m at 5 years of age. They grow well in equatorial to subtropical maritime climates at elevations of 1 to 1600 m with average rainfall of 100 to 240 cm. Growth is moderately rapid in early years, up to 1.5 m in height per year, but slows to around 0.5 m per year as trees reach maturity. Typical fruit yield is around 70 to 100 kg per tree per year. Jackfruit flowers are open-pollinated, resulting in highly variable seedlings. However, commercial growers normally plant grafted cultivars. The fruits of most cultivars weigh 10 to 30 kg, although the range for known cultivars extends from 2 to 36 kg. (Elevitch and Manner 2006) Elevitch and Manner (2006) provide details on propagation, cultivation, and harvesting, as well as traditional uses.
Jackfruit is an important tree in home gardens in India, the Philippines, Thailand, Sri Lanka, and other regions where Jackfruit is grown commercially and is perhaps the most widespread and economically important Artocarpus species, both providing fruit and functioning as a visual screen and ornamental. (Elevitch and Manner 2006)
The wood of Jackfruit, which ages to an orange or red-brown color, is highly durable, resisting termites and decay (Elevitch and Manner 2006). A yellow dye is sometimes extracted from the wood and used for dyeing clothes, especially in India and the Far East (Seddon and Lennox 1980).
Champedak (A. integer) is easily mistaken for Jackfruit (although rarely found in the Pacific), but has smaller and rounder fruits with less latex and a thicker rind. (According to Elevitch and Manner (2006), contrary to many sources, A. integer and its synonym A. integrifolia are not synonyms of A. heterophyllus).
Jackfruit is reportedly native to the rainforests of Malaysia and the Western Ghats of India, but today it is distributed far more widely. It has been cultivated since prehistoric times and has naturalized in many parts of the tropics, especially in Southeast Asia, where it is now an important crop in India, Burma, China, Sri Lanka, Malaysia, Indonesia, Thailand, and the Philippines. It is also grown in parts of Africa, Brazil, Surinam, the Caribbean, Florida, and Australia. It has been introduced to many Pacific islands since European contact and is of particular importance in Fiji, which is home to many people of Indian descent. (Elevitch and Manner 2006)