Artocarpus heterophyllus Lam.

Tree up to 10(-30) m tall, sometimes with short buttresses, evergreen. Leafy twigs 2-6 mm thick, minutely whitish appressedly puberulous (to subpunctate), smooth, drying brown to greyish; lenticels scattered. Leaves spirally arranged; lamina (sub)coriaceous, entire (or if juvenile 3-lobed), elliptic to (sub)obovate, 4-15 by 2-8(-12) cm, apex short-acuminate to obtuse, base cuneate to rounded, mostly ± decurrent, margin entire, ± revolute; upper surface often initially with sparse (retrorse) whitish uncinate hairs, soon glabrous, smooth; lower surface sparsely minutely whitish appressedly puberulous on the main veins or only on the midrib, often initially also sparse (retrorse) uncinate hairs, smooth; lateral veins 6-10 pairs, tertiary venation scalariform, slightly prominent; petiole 0.8-3 cm long, 1-2 mm thick, sparsely minutely whitish appressedly puberulous, the epidermis persistent; stipules fully amplexicaul, 1-5(-8) cm long, minutely whitish appressedly puberulous, caducous. Staminate inflorescences axillary or cauliflorous on slender leafy branchlets, solitary; peduncle 1-5.5 cm long, minutely whitish appressedly puberulous, at the apex broadened into a rim; head cylindrical to spicate or to subellipsoid, 2.5-7 by 0.8-2.8 cm; perianth tubular 0.7-1 mm long, the apex 2-lobed, minutely puberulous; stamen 1.5-2 mm long, anther c. 0.3 mm long; flower intermixed with numerous (to few?) cylindrical processes, these as long as the flowers, or processes absent. Pistillate inflorescences axillary, ramiflorous or cauliflorous on leafy branchlets, solitary; peduncle 3-10 cm long, minutely whitish (appressedly) puberulous, the apex broadened into a broad rim; head ellipsoidal to cylindrical; perianth tubular, white puberulous to subhispidulous, the apex convex; stigma simple; interfloral bracts (sometimes?) present, these peltate with the apical part 0.2-0.4 mm diameter. Infructescences ellipsoid to narrowly ellipsoid to pyriform, 30-100 by 25-50 cm, covered with c. 3 mm long conical to pyramidate apices of the perianths; fruits ellipsoid, c. 3 cm long.

A tropical plant. It grows in the tropical lowlands and up to about 1200 m altitude. It grows in Nepal up to 800 m altitude. It can stand some drought, but not water-logging. Trees do best where there is year round rainfall. An annual rainfall between 1,000-2,400 mm is best. It yields poorly where humidity is low. It does best in a well drained, frost-free location that is warm and sunny. They are slightly more tolerant of cold than breadfruit. It suits areas with a temperature range 22-35°C. Trees can survive occasional frosts down to 0°C. It is best with a pH of 6-6.5. They have some wind and salt tolerance. It grows between 25°N and 30°S. In XTBG Yunnan. It suits hardiness zones 10-12.

Cultivated for its edible fruit, especially in southeast Asia. Jackfruit is rich in nutrients, including carbohydrates, proteins, vitamins, minerals and phytochemicals (Ranasinghe et al. 2019). The fruit, leaves and bark have been used in traditional medicines. See Ranasinghe et al. (2019), and references therein, for a review of nutritional benefits and various uses including food products. See also Slik (2009) for uses, including cooking methods and food products, stock feed, dyes, tannin, timber and medicines.

Trees are usually sown from seeds, but it is best to sow them in their final location as the plants don't transplant easily. They have a long delicate taproot which makes transplanting difficult. Fresh seed must be used (less than 4 weeks). If fresh seed are planted immediately they grow more quickly and more seeds germinate. It is better to use larger seed. The fleshy layer around the seeds should be removed. Seeds can be soaked in water for 24 hours to give better germination. It is best to sow seeds with the embryo pointing downwards and also with the narrow end pointing downwards. Seeds germinate in 3-8 weeks. A spacing of 12 m is suitable. Where trees are used as a wind break, trees are spaced 6 m apart. Air-layering can be used, and stem cuttings are also possible. Air layering is best done in the rainy season. Rooting hormones can be used to help roots develop. The shoots used for air layering should be 2-3 years old and brown in colour. To produce air layers, a small branch 3-4 cm across, is cut below a node and only part way around the stem. A ring 5-7 cm wide is cut and a layer of sand wrapped around the stem and covered with plastic. Using 1% IBA growth substances helps shoots to strike and form roots. Roots form in about 22 days and the stem can be cut off and planted after about 2-3 months. Because trees vary in their growth rate, how quickly they flower and fruit, and in the fruit quality, it is best to grow plants by using vegetative parts from good trees. This can be done by budding or grafting onto 12 month old seedlings already established in the field. Budding and grafting are not easy with jackfruit. Because the fruit develops on the trunk, early pruning to allow 2-3 trunks to develop is helpful. As well, trees can be topped to prevent them becoming too tall and large.