Jack Fruit

In Brief:

Distribution Common in southeast Asia and found occasionally in Pacific island homegardens. Size Trees typically reach a height of 8–25 m (26–82 ft) and a canopy diameter of 3.5–6.7 m (11–22 ft) at 5 years of age. Habitat The tree grows well in equatorial to subtropical maritime climates at elevations of 1–1600 m (3.3–5250 ft) and average rainfall of 1000–2400 mm (40–95 in). Vegetation A common component in polycultures together with numerous other cultivated species. Soils Grows in freely draining, acid to neutral soils (pH 5.0–7.5). Growth rate Grows moderately rapidly in early years, up to 1.5 m/yr (5 ft/yr) in height, slowing to about 0.5 m/yr (20 in/yr) as trees reach maturity.

Main agroforestry uses Shade, windbreak, homegarden. Main products Fruit, timber, fodder, latex. Yields 70–100 kg/tree/yr (150–220 lb/tree/yr) is typical, although much larger yields have been reported. Intercropping It is interplanted with many other tree crops. Invasive potential Not considered invasive; naturalization in new environments is unusual.

INTRODUCTION:

Jackfruit (Artocarpus heterophyllus) is one of the most significant trees in tropical homegardens and perhaps the most widespread and useful tree in the important genus Artocarpus. It is a medium­size evergreen tree typically reaching 8–25 m (26–82 ft) in height that is easily recognized by its fruit, the largest among cultivated plants. The succulent, aromatic, and flavorful fruit is eaten fresh or preserved in myriad ways. The nutritious seeds are boiled or roasted and eaten like chestnuts, added to flour for baking, or cooked in dishes. It is also known for its remarkable, durable timber, which ages to an orange or red­brown color. The leaves and fruit waste provide valuable fodder for cattle, pigs, and goats. Many parts of the plant including the bark, roots, leaves, and fruit are attributed with medicinal properties. Wood chips yield a dye used to give the famous orange­red color to the robes of Buddhist priests.

The tree can provide many environmental services. It is highly wind tolerant and therefore makes a good component in a windbreak or border planting. Growing in pastures, it can provide fallen fruit for livestock, shade, and long­term timber. In homegardens, the dense jackfruit canopy can provide a visual screen and is very ornamental. Introduced to most Pacific islands after European contact, the tree can be found throughout the Pacific, mainly in multipurpose plants. It is easy to grow and more adaptable than some of the other common Artocarpus species such as breadfruit (A. altilis). It is not considered to be an invasive species.

DISTRIBUTION:

Native range

The tree is reportedly native to the rainforests of Malaysia and the Western Ghats of India.

Current distribution:

Jackfruit has been cultivated since prehistoric times and has naturalized in many parts of the tropics, particularly in Southeast Asia, where it is today an important crop of India, Burma, China, Sri Lanka, Malaysia, Indonesia, Thailand, and the Philippines. It is also grown in parts of Africa, Brazil, Suriname, the Caribbean, Florida, and Australia. It has been introduced to many Pacific islands since post­European contact and is of particular importance in Fiji, where there is a large population of Indian descent. In a 1985 survey, jackfruit was present on 10–24% of Indo­ Fijian sugarcane farms in western Viti Levu, Fiji (Thaman and Ali 1993). In comparison, mango (Mangifera indica), papaya (Carica papaya), drumstick tree (Moringa oleifera), Murraya koenigii, and tamarind (Tamarindus indica) were found on 75–100% of the farms. In Hawai‘i, it is occasionally found in homegardens, and it is sold in farmer’s markets, although commercial production is minor. Jackfruit is occasionally planted in backyard gardens in Guam. The species is also reported to have been introduced to Palau, Yap, Pohnpei, Nauru, Tabiteuea in Kiribati, Samoa, and other islands (Fosberg et al. 1979).

BOTANICAL DESCRIPTION:

Preferred scientific name:

Artocarpus heterophyllus Lam.

Family:

Moraceae (mulberry family)

Non-preferred scientific names:

• Artocarpus brasiliensis Gomez

• Artocarpus heterophylla Lam.

• Artocarpus maxima Blanco

• Artocarpus philippinensis Lam.

• Polyphema jaca Lour.

• Soccus arboreus major Rumph.

• Artocarpus integer (Thunb.) Merr and its synonym A. integrifolia

• L. f. are a different species (champedak), and these

• names have often mistakenly been used as synonyms for A.

• heterophyllus.

Common names:

• Pacific islands

• dapanapan (Yap)

• jack, jack tree, jackfruit, jak, jakfruit (English)

• jacquier (French)

• kapiak (Papua New Guinea)

• uto ni India (Fiji)

• ‘ulu initia (Samoa)

• Other?regions

• banun, khanun, makmi (Thai)

• buen pan, jaca, pan de fruta, rima (Spanish)

• chakki, kanthal, kathal, kathar, panos (Hindi)

• Jackfrutchbaum (German)

• langka, nancas (Filipino)

• nangka, nongko ( Javanese)

Size and form:

Jackfruit is a medium­size, evergreen tree that typically attains a height of 8–25 m (26–82 ft) and a stem diameter of 30–80 cm (12–32 in). The canopy shape is usually conical or pyramidal in young trees and becomes spreading and domed in older trees. The canopy diameter at 5 years old ranges from 3.5–6.7 m (11–22 ft) and can reach 10 m or more in older trees. The tree casts a very dense shade. Heavy side branching usually begins near the ground. All parts of the tree exude a sticky white latex when injured.

Flowers:

This species is monoecious, having male and female inflorescences (or “spikes”) on the same tree. Male and female spikes are borne separately on short, stout stems that sprout from older branches and the trunk. Male spikes are found on younger branches above female spikes. Male spikes are dense, fleshy, cylindrical to club­shaped, and up to 10 cm (4 in) in length. Flowers are tiny, pale green when young, turning darker with age. Female flowers are larger, elliptic or rounded, with a tubular calyx. The flowers are reportedly pollinated by insects and wind, with a high percentage of cross­pollination.

Leaves:

Leaves are dark green, alternate, entire, simple, glossy, leathery, stiff, large (up to 16 cm [6 in] in length), and elliptic to oval in form. Leaves are often deeply lobed when juvenile and on young shoots.

Fruit:

Jackfruit has a compound or multiple fruit (syncarp) with a green to yellow­brown exterior rind that is composed of hexagonal, bluntly conical carpel apices that cover a thick, rubbery, whitish to yellowish wall. The acid to sweetish (when ripe) banana­flavored flesh (aril) surrounds each seed. The heavy fruit is held together by a central fibrous core. Fruits are oblong­cylindric in shape, typically 30–40 cm (12–16 in) in length but sometimes up to 90 cm (35 in). They usually weigh 4.5–30 kg (10–66 lb), although a weight of 50 kg (110 lb) has been reported (Morton 1987). The heavy fruit is borne primarily on the trunk and interior part of main branches.

Fruits take 90–180 days to reach maturity. In the Northern Hemisphere, the main bearing season is late spring to early fall (between March and September). A few fruits mature in winter or early spring.

Seeds:

Seeds are light brown to brown, rounded, 2–3 cm (0.8–1.2 in) in length by 1–1.5 cm (0.4–0.6 in) in diameter, and enclosed in a thin, whitish membrane. Up to 500 seeds can be found in each fruit. Seeds are recalcitrant and can be stored up to a month in cool, humid conditions.

Rooting habit:

Jackfruit has a strong taproot. Similar species Champedak (Artocarpus integer [Thunb.] Merr.) is easily mistaken for jackfruit. There are several indicators differentiating the two species; perhaps the easiest to see is that champedak has smaller, rounder fruits, with less latex and thicker rind. However, champedak is rarely found in the Pacific.

Genetics:

Variability of species:

Because the flowers are open­pollinated, there is usually great variation in seedlings. Variation is exhibited in a wide range of characteristics such as tree size and structure, leaf and fruit form, age to bearing, and fruit quality. Fruit size, shape, and color of the fruit and texture, odor, and taste of the edible pulp vary tremendously. An exception is the ‘Singapore’ (or ‘Ceylon’) cultivar, which bears comparatively quickly from seed—usually in 18–30 months—and is relatively true to type. It has medium­size fruits (6–12 kg [13–26 lb]) with soft, fibrous, and very sweet flesh.

Known varieties:

Commercially, grafted cultivars are normally planted. The fruit of most cultivars weighs 10–30 kg (22–66 lb), although the full range of known cultivars is 2–36 kg (4.4–79 lb) and even heavier. The fruit is generally grouped into two major types by fruit quality: 1) thin, fibrous, and mushy edible pulp, usually very sweet and emitting a strong odor, and 2) thick, firm, often crisp, less fragrant pulp. There are numerous cultivars of each type in regions where jackfruit is a significant food crop, including South India, Thailand, Malaysia, the Philippines, and Ceylon. In Hawai‘i, grafted cultivars include ‘Black Gold’, ‘Dang Rasimi’, ‘Golden Nugget’, ‘Honey Gold’, and ‘NS1’. Jackfruit usually has two main seasons; in Hawai‘i it bears in May–August and November–January. Details on these and other cultivars are available from several excellent references (e.g., Crane et al. 2002, Campbell and Lesdesma 2003, and Morton 1987) and in Tables 1 and 2 below.

Culturally important related species in the genus Jackfruit belongs to the genus Artocarpus, a genus rich in culturally important species including breadfruit (A. altilis), dugdug (A. mariannensis), and breadnut (A. camansi). These three species represent some of the most important traditional subsistence trees of Pacific islands. Elsewhere in Southeast Asia and India, champedak (A. integer), lakoocha (A. lakoocha), marang (A. odoratissima), kwai muk (A. lingnanensis), and others are important fruit trees, all with culturally important uses, and many with other valuable products, such as timber.

ASSOCIATED PLANT SPECIES:

Associated native species commonly found Jackfruit is reported as a locally common endemic tree species of the evergreen and semi­evergreen forests of the Western Ghats of India. These mountains are a center of biodiversity where more than 800 species of trees have been recorded. Ramesh (no date) classifies the vegetation of the Western Ghats into the following: Wet evergreen forests (with three subtypes based on elevation, with the highest located above 1400 m [4600 ft]); dry evergreen forests; moist deciduous forests; dry deciduous forests; and grasslands. In these forests, jackfruit is one of 352 endemic tree species.

Species commonly associated as aboriginal introductions in Pacific islands Jackfruit is a post­European­contact introduction to Pacific islands. The tree is commonly planted in smallholder cane farms in Fiji held by farmers of Indian ancestry. It is occasionally found in small farms and homegardens throughout the Pacific. Associated tree species include breadfruit (Artocarpus altilis), dugdug (A. mariannensis), betel nut palm (Areca catechu), coconut (Cocos nucifera), Musa textilis, M. paradisiaca, M. sapendium, mango (Mangifera indica), Annona spp., Pangium edule, cocoa (Theobroma cacao), Eugenia spp., and guava (Psidium guajava). Jackfruit is found growing together with more than 50 tree species in Yapese homegardens (Falanruw 1990). It is found occasionally on farms and in homegardens throughout Hawai‘i.

Species commonly associated in modern times or as recent Pacific island introduction The tree is often found as a component of homegardens in many tropical regions, albeit few in number at each site. One example from Java shows but one jackfruit tree among a listing of 39 homegarden plants (Abdoellah 1990). The species is also a common associate of village tree gardens. Other tree species include durian (Durio zibethinus), Gnetum gnemon, Eugenia polycephala, Mangifera caesia, coffee (Coffea robusta), Pangium edule, and bilimbi (Averrhoa bilimbi), to name a few (Michon and Mary 1990).

ENVIRONMENTAL PREFERENCES AND TOLERANCES:

Jackfruit grows in a wide range of tropical to subtropical environments. It is most common in lowland forests up to 250 m (820 ft), decreasing in abundance up to 1000 m above sea level; it thrives best in moist tropical environments below 1000 m (3300 ft). Although tolerant of cooler environments up to 1600 m (5250 ft), jackfruit may suffer dieback in light frosts and does not tolerate freezing temperatures. It bears fruit at latitudes of up to 30° from the equator, with good crops at latitudes within ±24°.

Climate:

The tree grows well in the equatorial to subtropical maritime climates of the Indian and Pacific oceans. It is a component of the tropical moist (rainforest) to semi­dry forest.

Elevation range

1–1600 m (3.3–5250 ft)

Mean annual rainfall

1000–2400 mm (40–94 in)

Rainfall pattern

It favors environments with a uniform rainfall pattern, although it will grow in seasonally dry climates.

Dry season duration

(consecutive?months?with?< 0 mm?[1. ?in]?rainfall) 2–4 months

Mean annual temperature

24–28°C (75–82°F)

Mean maximum temperature of hottest month

32–35°C (90–95°F)

Mean minimum temperature of coldest month

16–20°C (61–68°F)

Minimum temperature tolerated

­3–0°C (27–32°F)

Soils:

Jackfruit grows best in well drained, deep soils of moderate fertility but tolerates a wide range of soils including shallow limestone, sand, and rocky substrates. The tree does not tolerate water stagnation or poor drainage. If the roots touch stagnant water, the tree fails to bear fruit, or it may die.

Soil texture

The tree can grow in light­ and medium­texture soils (sands, sandy loams, loams, and sandy clay loams).

Soil drainage

It requires free drainage.

Soil acidity

The tree tolerates moderately acid to neutral soils (pH

5.0–7.5).

Special soil tolerances

Jackfruit tolerates shallow, slightly saline, and infertile soils. It also tolerates high pH limestone soils, rocky, and laterite soils.

Tolerances:

Drought:

Jackfruit tolerates 3–4 months of drought. However, it does best with even and continuous soil moisture.

Full sun:

The tree prefers full sun at maturity.

Shade:

Seedlings are best grown in 30–50% sunlight, with sun exposure increasing to 100% as the tree matures.

Frost:

Jackfruit is more cold­tolerant than other species in the genus and can even tolerate light frost. At 0°C (32°F) the leaves may be damaged, and at –2°C (28°F), branches or the whole tree may die.

Waterlogging:

The tree does not tolerate waterlogging or poor drainage and will decline and die if roots become waterlogged for more than a day or two.

Salt spray

Jackfruit has moderate tolerance for salt spray.

Wind

The tree tolerates moderate wind quite well and has been known to survive hurricane­force winds, recovering from loss of leaves and small limbs.

Abilities

Self-prune:

Jackfruit tends not to self­prune, instead retaining side branches along the main trunk. Even when side branches are pruned off, fruiting branchlets continue to sprout on the lower trunk.

Coppice:

The tree regrows well even after heavy pruning.

GROWTH AND DEVELOPMENT:

Jackfruit is a rapid grower, reaching a height of 3 m (10 ft) and canopy diameter of 2 m (6.6 ft) in 2 years. Height growth for the first few years is about 1.5 m/yr (5 ft/yr), slowing to 36–60 cm/yr (14–18 in/yr) (Acedo 1992). A 20­ year­old tree can reach 17.5 m (57 ft) in height and 20 cm (8 in) in trunk diameter (Morton 1987). While trees can live to 100 years of age, their removal and replacement in Thailand plantations after 20 years of growth suggests a significant decrease in productivity with age.

Flowering and fruiting:

Seedlings usually take 4–14 years before bearing fruit, although the ‘Singapore’ (or ‘Ceylon’) cultivar begins bearing fruit 18–30 months after transplanting (Morton 1987). Fruits of most cultivars reach maturity in middle to late summer. Morton (1987) reports that in Asia, depending on the climatic region, fruits ripen mainly from March to June, April to September, or June to August, with some offseason crops from September to December.

Reaction to competition:

Jackfruit seedlings grow slowly in heavy shade. Weeding is recommended to lessen competition for light, water, and nutrients.

PROPAGATION

(after Wilkinson and Elevitch 2003) Jackfruit seedlings are very easy to grow. Seedlings devel­ op very quickly, reaching 25 cm (10 in) in height within 3–4 months. Seeds are cross­pollinated and therefore not true­to­type, so grafting known varieties onto rootstocks is often done, especially for commercial production where a uniform product with the best market qualities is important. Because the seeds are large and grow quickly and their root systems are sensitive to damage during transplanting, direct­seeding in the field can give the best results. Fieldsown seedlings can be top­worked (grafted) with select varieties once they are established. Propagation by vegetative means such as cuttings and air­layering is also possible, although uncommon.

Seedlings:

Growing area

Seeds are sown at a depth of 2 cm (0.8 in), and can be laid flat or planted with the hilum pointing down.

Germination:

Germination begins in 1–3 weeks, or longer (up to 6 weeks) if seeds were stored more that a few days after collection. Daily watering is often necessary once seeds germinate.

Media:

A well drained medium is recommended, such as 50% peat moss, 25% perlite, 25% vermiculite amended with a little compost, dolomite lime, gypsum, and a 14­14­14 slow­release or an organic fertilizer. In the nursery, 2–4 l (2–4 qt) root­training containers work well. The seedlings should not be allowed to root through the container into the underlying substrate, as the roots would have to be cut or broken for transplanting.

Approximate size at outplanting:

Seedlings have reached target size when approximately 20 cm in height and have a stem diameter of 9 mm (0.35 in). This takes about 3–4 months in good growing conditions.

Guideline for outplanting:

If seedlings are grown in the nursery, it is crucial to outplant them before they become root­bound. Transplanting seedlings when they have just filled out their growing container will ensure minimal trauma to the root system. In ideal conditions, field survival of about 90% can be expected.

Direct-seeding:

Direct­seeding in the field is the best propagation method if the planting locations are well prepared, weed free, and frequently tended for the first 6–12 months of growth. It eliminates any transplant trauma. In direct­seeding, an area is prepared for each planting spot, cleared of weeds, and cultivated to a depth of 50 cm (20 in) if the soil is compacted. Seeds are planted at a depth of 2–3 cm (0.8–1.2 in). Sowing several seeds at each site allows for selecting the most vigorous seedling and can prevent the necessity of reseeding. The drawbacks of direct­seeding include risk of predator damage (e.g., rats, pigs, cattle, etc.), lack of rains to sustain the newly germinated seeds, and the mandatory frequent maintenance that must be done to ensure weeds do not overcome the seedlings.

Seed collection:

Trees usually bear fruit in two main seasons, although offseason fruiting is common. Collect seeds from fruits of trees with outstanding growth and fruit qualities.

Seed processing:

After opening the fruit with a large knife, seeds are separated from the fleshy sheaths that enclose the seeds. Each fruit contains 100–500 seeds; there is no correlation between fruit size and the number of seeds it contains. There are about 50–90 seeds/kg (23–41 seeds/lb). The thin, slimy coating around the seed (perianth lobe) should be removed and the seeds thoroughly rinsed in water to remove any remaining pulp juice or sugary residue. Only the largest seeds should be used, as these will give the earliest and highest germination and produce the strongest seedlings. Seeds may be air­dried in the shade for about an hour for ease of handling, but they should not be allowed to dry out, as this will kill them. Germination for seed sown within a few days of harvesting is usually high, around 90%.

Seed storage:

Seeds are recalcitrant, i.e., they do not retain viability when dried or stored for extended periods. They should be planted immediately for best germination and seedling vigor. Seeds can be stored moist in a plastic container in the refrigerator for up to a few weeks. Stored seeds germinate more slowly than fresh seeds.

Seed pretreatment:

No pretreatment is required. However, soaking in water or a dilute gibberellic acid solution for 24 hours prior to sowing hastens germination and is recommended. Hot water treatment has been used successfully to stimulate germination (Oyen and Dung 1999).

DISADVANTAGES:

Jackfruit is susceptible to damage by a wide number of boring insects and plant diseases. Although the tree is long­ lived, the recommended practice in some regions is to remove 20­year­old trees because of declining productivity. Some people find the aroma of the fruit to be objectionable, particularly in confined spaces.

Potential for invasiveness:

Jackfruit does not spread readily and is not considered invasive. In most areas of the world where jackfruit is grown, its presence is indicative of human cultivation.

Pests and diseases:

In southwestern and southern Asia, boring insects seem to be the major pests of jackfruit. These include Indarbela tetraonis, Batocera rufomaculata, Margaronia caecalis, and Ochyromera artocarpio (Morton 1987). In India the main insect pests are the shoot­boring caterpillar (Diaphania caesalis), mealybugs (Nipaecoccus viridis, Pseudococcus corymbatus, and Ferrisia virgata), spittle bug (Cosmoscarta relata), and jack scale (Ceroplastes rubina). In southern China, the fruit stem is susceptible to damage from the larvae of the longicorn beetles Aprona germarri, Pterolophia discalis, Xenolea tomenlosa asiatica, and Olenecamptus bilobus. The caterpillars of leaf webbers (Perina nuda and Diaphania bivitralis), aphids (Greenidea artocarpi and Toxoptera aurantii), and thrips (Pseudodendrothrips dwivarna) are minor problems (Morton 1987).

Important diseases of jackfruit are pink disease (Pelliculana [syn. Corticum] salmonicolor); stem, fruit, and male inflorescence rot caused by Rhizopus artocarpi; and leafspot due to Phomopsis artocarpina, Colletrotrichum 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 (Morton 1987). According to Crane et al. (2002), wood boring insects in Florida include Elaphidion mucronatum, Nyssodrysina haldemani, and Leptostylopsis terraecolor. Various scales and mealybugs may attack stems and fruit. Diseases include Rhizopus fruit rot (Rhizopus artocarpi), gray mold (Botrytis cinerea), root rot (Pythium splendens, Phytophthora spp., Fusarium spp., and Rhizoctonia spp.), and leaf spotting by fungi (Gloeosproium sp. and Phyllosticta artocarpi).

Other disadvantages:

The fruit is relatively uncommon in many parts of the Pacific including Hawai‘i, and the large size and characteristic odor can be deterrents in the marketplace. Young plants require protection from grazing animals and sun scald. In plantations, fairly wide spacing between trees is required in order to reduce competition for light, water, and nutrients.

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