Jackfruit: Botany, Production and Uses

1 Botany, Origin, History and Production

Michel Chauvet¹* and Sisir Mitra²

¹15 Avenue du Quartier Bas, 34230 Vendémian, France; ²Former Professor, Faculty of Horticulture, Bidhan Chandra Krishi Viswavidyalaya, West Bengal, India

*Corresponding author: [email protected]

©CAB International 2023. Jackfruit : Botany, Production and Uses (ed. S. Mitra)

DOI: 10.1079/9781800622319.0001

1.1 The Family Moraceae

Moraceae is a family of 37 genera and approximately 1100 species, which extends worldwide, mainly in tropical areas, with some species in subtropical and temperate regions.

The family consists of trees, shrubs, climbers and herbs, usually with milky latex. The leaves are alternate, rarely opposite or subverticillate, most frequently simple and entire, sometimes dentate, palmately veined, pinnately or palmately incised, and rarely pinnate or palmate. Some species show both entire and lobed leaves on the same tree (Broussonetia papyrifera), or lobed leaves when juvenile (Artocarpus heterophyllus). Stipules are present and often conspicuous.

The inflorescences are extremely diverse. They may be bisexual or unisexual, and racemose or cymose to capitate or urceolate. Pistillate inflorescences are sometimes uniflorous. The flowers are unisexual, perianth simple with (0–)4(–10) persistent tepals. The flowers are staminate with (1–)4(–6) stamens. The flowers are pistillate with a unilocular, superior to inferior ovary, one or two styles and stigmas, and one ovule.

The fruits are rarely dry, more frequently drupaceous, usually enveloped by a fleshy perianth or immersed in a fleshy receptacle, often with the whole infructescence forming a syncarp. In their extreme form (e.g. Artocarpus, Parartocarpus), these syncarps are so highly integrated that their constituents (tepals, bracts and axial tissue) cannot be identified with certainty. The large syncarps of Artocarpus reach a weight of up to 50 kg.

Ficus pollination has attracted a lot of attention. The pollinators are agaonid wasps, and each Ficus sp. depends on a particular wasp. Little is known about the pollination of other Moraceae.

Individual drupes or small syncarps are usually brightly coloured and dispersed by birds. Larger syncarps are less coloured but odoriferous, and are dispersed by mammals. In some cases, sticky fruits suggest exozoochory.

A common feature of the family is the latex. Its composition is rather variable, with rubber, proteins, waxes, triterpenoid resins, polyphenols and cardenolides being the main components. In some species of Ficus, papain-like enzymes can be found.

1.2 Taxonomy

In the past, members of the order Urticales (Urticaceae, Moraceae, Cannabaceae, Ulmaceae) were kept separate from the Rosaceae, largely because of their very reduced and usually wind-pollinated flowers, but they have now been merged into the order Rosales (Stevens, 2001; Sytsma et al., 2002).

The subdivision of the family Moraceae is not yet stabilized. According to Zerega et al. (2010), the tribes are Moreae, Artocarpeae, Castilleae, Dorstenieae and Ficeae. Ficeae has only one genus, Ficus. Within Moreae (ten genera), the genus Maclura is sometimes put into a separate tribe, Maclureae. Artocarpeae (five genera) includes Parartocarpus and Hullettia. Castilleae (11 genera), previously Olmedieae, now excludes the genus Olmedia, which is included in the genus Trophis. Dorstenieae contains nine genera, but the genus Treculia is sometimes included in Artocarpeae.

1.3 Distribution

The Moraceae are a pantropical family, with some members in subtropical and northern temperate regions. Most Moraceae are components of humid tropical lowland forests, but many species are also found in drier tropical or subtropical habitats. Ficus is the only pantropical genus, with a centre of diversity in Asia–Australasia. Dorsteniae are represented in tropical America and tropical Africa, while Castilleae are mainly neotropical. Moreae are the only tribe including truly temperate representatives (species of Morus and Maclura); the majority of its species, however, are tropical, with a centre of diversity in South-east Asia. Artocarpeae are neotropical and Asian, with the genus Treculia found in Africa.

Most species are evergreen, but Broussonetia, Morus and some species of Artocarpus, Ficus and Maclura are deciduous.

1.4 Economic Importance

The most important products of the Moraceae are fruits: breadfruit (Artocarpus altilis), jackfruit (Artocarpus heterophyllus), figs (Ficus spp., especially Ficus carica and Ficus sycomorus) and to a lesser extent mulberries (Morus spp.) and Antiaris toxicaria. Brosimum alicastrum gives an edible nut.

Artocarpus odoratissimus is cultivated in Borneo and the Philippines for the sweet pulp around the seed. Artocarpus nitidus, with the uniformly succulent kind of infructescence, is sometimes found in gardens in West Malesia, where it is also used for jam and conserves.

Many species yield valuable timbers: iroko (Milicia excelsa) in tropical Africa, letterwood or snakewood (Brosimum guianense) in the Guyanas, muirapiranga (Brosimum rubescens) in Brazil, Osage orange (Maclura pomifera) from North America, Antiaris toxicaria, Streblus elongatus and several species of Artocarpus in Asia.

A fine paper is prepared from the bark of the paper mulberry (Broussonetia papyrifera) in Asia. Tapas (bark tissues) are also obtained from this species, as well as from Artocarpus elasticus, Artocarpus altilis and Ficus prolixa in Oceania.

Morus alba is grown extensively for its leaves, which feed the larvae of the silkmoth (Bombyx mori). Maclura pomifera is sometimes used in India for that purpose.

The latex of many species is used locally, usually as an arrow poison (Antiaris toxicaria and Parartocarpus venenosus) or as a glue (Artocarpus spp.). Some species (Castilla elastica, Ficus elastica) have been grown as a source of rubber but are largely replaced nowadays by Hevea brasiliensis (Euphorbiaceae). Other species yield a yellow dye, such as Maclura pomifera, Maclura cochinchinensis and Artocarpus heterophyllus (Cardon, 2007). Brosimum acutifolium produces a psychotropic drug called takini (Grenand et al., 2004), as does Maquira sclerophylla. Dorstenia contrajerva has long been renowned as a medicinal against snake bites.

Many species also have ornamental value (e.g. Ficus benjamina, Ficus elastica, Ficus lyrata, Broussonetia papyrifera, Maclura pomifera), or are used as shade trees. The banyan (Ficus benghalensis) and the peepal (Ficus religiosa) are sacred trees in India, while Ficus sycomorus has a high prestige in the Near East.

1.5 The Tribe Artocarpeae

Artocarpeae has long been a heterogeneous, ill-defined and ever-changing tribe within the Moraceae (Jarrett, 1959a; Corner, 1962; Rohwer, 1993; Berg, 2001; Datwyler and Weiblen, 2004; Berg et al., 2006; Clement and Weiblen, 2009). Based on evidence from phylogenetic analyses of molecular data, and considering morphological characters, Zerega et al. (2010) circumscribed a monophyletic Artocarpeae comprising two neotropical (Clarisia and Batocarpus) and one paleotropical (Artocarpus including Prainea) genus. Three genera have been removed from recent circumscriptions of Artocarpeae: Parartocarpus and Hullettia form a monophyletic group that may warrant tribal status, and Treculia has been transferred to Dorstenieae.

Artocarpeae as defined by Zerega et al. (2010) are supported by a reduction in stamen number within the family. Members of the genera Artocarpus, Prainea, Clarisia and Batocarpus all have one (or less frequently two in Batocarpus and Artocarpus annulatus, and one to three in Clarisia) stamen per flower compared with the more typical two to five in other Moraceae. The typical number of stamens per flower in the Moraceae is four, but exceptions exist in all of the tribes.

Artocarpeae bear unisexual flowers, as do all Moraceae, and typically have unisexual inflorescences. Pistillate inflorescences are condensed capitate heads (or rarely uniflorous as in some Clarisia spp.), which develop into syncarps (Jarrett, 1959c). Both pistillate and staminate inflorescences typically comprise numerous small, tightly packed flowers, which sit on a fleshy receptacle, and have a perianth (Jarrett, 1959a).

Staminate inflorescences are spicate or less frequently globose. They have numerous flowers with two to four connate tepals, and typically one stamen (occasionally two to three may be present) that is straight in bud.

Pistillate inflorescences have one to more typically numerous flowers with two to four connate tepals, and adjacent perianths may be free or partially to completely fused to one another. This allows the entire inflorescence to develop into a highly specialized syncarp formed by the enlargement of the entire female head, even if only a portion of the flowers develop seeds (Jarrett, 1977). However, in Prainea, Batocarpus and Clarisia spp., adjacent pistillate perianths remain free so that only fertilized ovules enlarge.

Members of the Artocarpeae can be latex-producing trees, shrubs or, rarely, climbers, and are either monoecious or dioecious. The leaves are simple (rarely compound), spirally alternate or distichous, and have either amplexicaul or non-amplexicaul stipules. The inflorescences are typically axillary but are cauliflorous in a few species. Interfloral bracts may be present or absent.

1.5.1 Key to the genera of Artocarpeae

1. Staminate inflorescences spicate with a distinct abaxial sterile strip; staminate flowers crowded in longitudinal rows; leaves alternate and distichous with lateral stipules; neotropical in distribution…………2

1. Staminate inflorescences spicate to globose to obovoid or clavate, lacking a distinct abaxial sterile strip; staminate flowers crowded but not in longitudinal rows; leaves alternate and distichous with lateral stipules or spirally alternate with amplexicaul stipules; paleotropical in distribution………… Artocarpus

2. Inflorescences axillary; pistillate inflorescences multiflorous and globose-capitate; fruiting perianth green………… Batocarpus

2. Inflorescences often cauliflorous, or, if axillary, then bark at base of the trunk reddish; pistillate inflorescence suniflorous or multiflorous and discoid-capitate; fruiting perianth red, orange, pale yellow or greenish-yellow ………… Clarisia

1.6 The Genus Artocarpus

Artocarpus J.R. Forster & G. Forster (1776), nom. cons.

Synonyms:

•Sitodium Banks & Sol. ex Parkinson (1773)

•Radermachia Thunb. (1776) (‘Rademachia’)

•Prainea King ex Hook. f. (1888)

•Saccus O. Kuntze (1891)

Artocarpus is a nomen conservandum, against the earlier name Sitodium. The name is formed from the Greek ρτος (artos) for ‘bread’ and καρπός (karpos) for ‘fruit’. Forster, who coined the name, writes: ‘The fruit is locally used as bread.’ Breadfruit, Artocarpus altilis (Parkinson) Fosberg, is indeed an important starchy vegetable in Oceania.

Table 1.1. Major species of Artocarpus and their vernacular/common names. From Ghosh (2000).

The genus Artocarpus J.R. Forst. & G. Forst. (Moraceae) contains approximately 70 species of monoecious trees. Its range extends from India to the Solomon Islands, with a centre of diversity in Borneo (Williams et al., 2017). Notable species include the widely cultivated A. altilis (Parkinson) Fosberg (breadfruit) and Artocarpus heterophyllus Lam. (jackfruit), in addition to other species of more regional importance, such as Artocarpus integer (Thunb.) Merr. (chempedak) and Artocarpus odoratissimus Blanco (terap) (Table 1.1). Sixteen species of Artocarpus occur in Singapore, of which 14 are indigenous to the island (Table 1.2) (Gardner and Zerega, 2021).

Artocarpus was revised by Jarrett (1959a, b) with subsequent taxonomic work by Kochummen (1978) and Berg et al., 2006Berg et al., 2011. The subgenera were revised following a phylogenetic study by Zerega et al. (2010), leading to four subgenera being distinguished. Additional phylogenetic work has provided a molecular framework for taxonomic revisions (Williams et al., 2017; Gardner et al., 2021). Gardner and Zerega (2020) updated the Artocarpus subgenus Pseudojaca Trécul, with a particular focus on the taxa in Singapore. Artocarpus griffithii (King) Merr. has been reinstated as distinct from Artocarpus lamellosus Blanco (which is called Artocarpus nitidus Trécul in the earlier literature), also requiring the reinstatement of the following taxa not found in Singapore: Artocarpus borneensis (Merr.) F.M. Jarett, Artocarpus humilis Becc., Artocarpus vrieseanus Miq. var. subsessilis F.M. Jarrett and Artocarpus xanthocarpus Merr. Artocarpus dadah Miq. has been reinstated as distinct from Artocarpus lacucha Roxb. ex Buch.-Ham., thereby necessitating the reinstatement of the following taxa not found in Singapore: Artocarpus fretessii Teijsm. & Binn. ex Hassk., Artocarpus ovatus Blanco and A. vrieseanus var. refractus (Becc.) F.M. Jarrett. Artocarpus gomezianus Wall. ex Trécul is restricted to the type subspecies, and A. zeylanicus (F.M. Jarrett) E.M Gardner & Zerega, formerly a subspecies, has been elevated to species level.

Table 1.2. Artocarpus species occurring in Singapore, with relevant taxonomic changes noted. Adapted from Gardner and Zerega (2021).

*species found primarily in cultivation. Taxa in bold belong to Artocarpus subgenus Artocarpus.

Gardner and Zerega (2021) recently made taxonomic updates of Artocarpus subgenus Artocarpus based on 517 nuclear genes. They proposed the following: Artocarpus subgenus Cauliflori (F.M. Jarrett) Zerega is reduced to a section within the Artocarpus subgroup Artocarpus, and Artocarpus section Glandulifolium F.M. Jarrett is raised to subgenus status. The new monotypic subgenus Artocarpus subgenus Aenigma E.M. Gardner & Zerega is proposed for Artocarpus sepicanus Diels, whose phylogenetic position remains uncertain and may be of ancient hybrid origin. Artocarpus elasticus Reinw. ex Blume, Artocarpus scortechinii King and Artocarpus corneri Kochummen are recognized as distinct species. Artocarpus clementis Merr. is reinstated as a distinct form of Artocarpus lanceifolius Roxb. Artocarpus calophyllus Kurz and Artocarpus melinoxylus Gagnep. are reinstated as distinct from both Artocarpus chama Buch-Ham. and Artocarpus rigidus Blume. Elmer is reinstated as distinct from Artocarpus treculianus Elmer.

Artocarpus species are monoecious trees, except in the subgenus Prainea, which is dioecious and includes a climber (Artocarpus scandens). The leaves are simple (rarely compound: Artocarpus anisophyllus), alternate and spiral (subgenera Artocarpus and Cauliflori) or alternate and distichous (subgenera Pseudojaca and Prainea), with large fully amplexicaul stipules (subgenera Artocarpus and Cauliflori) or small lateral stipules (subgenera Pseudojaca and Prainea).

The inflorescences are capitate, the head being cylindric to clavate, obovoid, ellipsoid or globose, and occasionally rami- or cauliflorous, with numerous flowers. Staminate flowers are free, usually mixed with peltate to clavate interfloral bracts, and the perianth is tubular, entire or two to four lobed, with one stamen and no pistillode. Pistillate flowers are at least distally connate with each other or with interfloral bracts, the perianth is tubular, thin-walled below and thick-walled above, and the apices either completely fused, forming an areolate surface, or free, forming variously shaped processes on the surface. The ovary is free, and the stigmas are one or two, equal or unequal.

The fruit is a syncarp, with at least the lower part of the perianth (the middle layer of the syncarp) becoming fleshy, and sometimes the entire head.

Pollination syndromes in Artocarpeae are still largely unknown, and empirical studies will be necessary for further elucidation. Phylogenetic classification will be a useful tool to understand and interpret pollination in an evolutionary context.

1.6.1 Key to the subgenera of Artocarpus

1. Perianths of adjacent pistillate flowers entirely free from one another; only fertilized flowers enlarging at maturity…………subgenus Prainea

1. Perianths of adjacent pistillate flowers partially to completely fused to form a syncarp; entire pistillate head enlarging at maturity…………2

2. Leaves distichous; stipules lateral and non-amplexicaul, less than 1 cm, stipule scar not annulate; pistillate inflorescences with adjacent perianths fused apically, giving the inflorescence and syncarp a smooth/uniform surface…………subgenus Pseudojaca

2. Leaves spirally alternate; stipules fully amplexicaul, 1 cm or longer, leaving an annulate stipule scar; pistillate inflorescences with adjacent perianths fused only medially, leaving perianth apices free and giving the inflorescence and syncarp a spiky or bumpy surface…………3

3. Inflorescences always axillary …………subgenus Artocarpus

3. Inflorescences develop directly from the trunk or branches of the previous year’s growth (cauli- or ramiflorous). Axillary inflorescences may also be present and male inflorescences may have ring-like constrictions (in Artocarpus annulatus ) …………subgenus Cauliflori .

1.6.2 Subgenus Artocarpus (synonym: subgenus Jaca Trécul (1847))

Breadfruit, A. altilis (Parkinson) Fosberg (1941), is by far the most important economic species of the subgenus Artocarpus. Its starchy fruits are a staple in Oceania. It probably originates from New Guinea and spread early on over all Oceania up to Hawaii and later to all tropical countries. Two types are known, one with seeds (breadnut) and one without seeds, which is reproduced vegetatively. It belongs to a complex of species that Jarrett (1959c) treated as one highly variable pantropical species (Ferrer-Gallego and Boisset, 2018). Zerega et al. (2005) distinguish two more species from A. altilis, Artocarpus camansi Blanco (1837) from New Guinea, and Artocarpus mariannensis Trécul (1847) from Palau and the Northern Mariana Islands, and their hybrids. Berg et al. (2006) included Artocarpus horridus F.M. Jarrett (1959) (the Moluccas), Artocarpus blancoi (Elmer) Merr. (1923), Artocarpus multifidus F.M. Jarrett (1959) and Artocarpus pinnatisectus Merr. (1921) (the last three from the Philippines), considering them all to represent a range of variation from wild to cultivated forms of breadfruit.

Recently, Gardner et al. (2021) identified a new species in the breadfruit clade from North Maluku, Indonesia, Artocarpus bergii E.M. Gardner, Arifiant and Zerega. This is a monoecious tree, of height at least 22 m; the leaves are spirally arranged, with the lamina subcoriaceous, elliptical to subobovate, and 11–29 × 5–14.5 cm; the apex is short-acuminate, acute to nearly rounded, base acute to obtuse. The staminate inflorescence (at anthesis) is in the leaf axil and solitary; the peduncle is 38–54 × 2 mm and pale green. The pistillate inflorescence (postreceptive) is in the leaf axil and solitary; the peduncle is 66–70 × 2.5 mm and pale green. The syncarp is cylindrical, 45–70 × 18–25 mm, and the surface is yellow when ripe.

Breadfruit is an evergreen tree (12–15 m up to 21 m). A. altilis tends to have a denser, more spreading canopy than A. camansi. The leaves (15–60 cm or longer) are alternate and broadly obovate to ovate, almost entire to deeply pinnately dissected with one to six pairs of lobes. The fruits (10–30 cm long × 9–20 cm wide) are variable in shape, size and surface texture. They are usually round, oval or oblong, weighing 0.25–6 kg. Skin texture varies from smooth rough to spiny. The colour is light green, yellowish-green or yellow when mature, although an unused variety (Afara, from French Polynesia) has pinkish or orange-brown skin (Ragone, 2006a). The flesh is creamy white to pale yellow. The fruits are typically mature and ready to cook as a starchy staple in 15–19 weeks (Worrell et al., 1998). Ripe fruits have a yellow or yellow-brown skin and a soft, sweet, creamy flesh that can be eaten raw or cooked. The fruits contain none to many seeds depending on the cultivar. The seeds are obovoid or rounded, irregularly compressed, 1–3 cm long and pale to dark brown in colour (Ragone, 2007; Zerega and Ragone, 2016).

Breadnut (A. camansi Blanco) is one of the wild progenitors of breadfruit (Ragone, 2006b). Breadnut is scattered throughout the lowlands of New Guinea where it occurs naturally, and is also found cultivated in home gardens. It only occurs in cultivation in the Philippines where it is typically grown as a backyard tree. It is infrequently grown in the Pacific outside its native range. A few trees are found in New Caledonia, Pohnpei, Marquesas, Tahiti, Palau and Hawaii, introduced by immigrants from the Philippines (Ragone, 2007). The tree typically forms buttresses at the base of the trunk and has a more open branching structure (Fig. 1.1A) than A. altilis or A. mariannensis. The leaves are alternate, large (40–60 cm long) and moderately dissected with four to six pairs of lobes and sinuses cut halfway to the midrib. The fruits are oval (10–15 cm × 7–12 cm) weighing approximately 800 g (Ragone, 2006a). The spiny skin, with pointed, flexible 5–12 cm elongated sections, is dull green to greenish-brown when ripe (Fig. 1.1B). The fruit contains numerous seeds comprising 30–50% or more of the fruit weight (Bennett and Nozzolillo, 1987). The seeds are typically obovoid or flattened by compression, 2.5 cm long with a thin, light brown seedcoat patterned with darker veins (Ragone, 2007).

Fig. 1.1. The tree (A) and fruit (B) of Artocarpus camansi tree. Photographs courtesy of Dr N.J.C. Zerega.

Chebiei or Dugdug (A. mariannensis Trécul) is cultivated through Micronesia for its edible fruits and seeds (Ragone, 1997, 2001) and has naturally hybridized and introgressed with A. altilis (Fosberg, 1960; Ragone, 1997, 2001; Zerega et al., 2004, 2005). Trees of A. mariannensis and hybrid cultivars tend to be more massive than A. altilis and A. camansi, with large trunks, extensive buttresses and full, rounded canopies. The leaves are alternate, 15–30 cm long, broadly obovate to broadly elliptic, and typically entire or shallowly one to three lobed on the upper third of the blade. The fruit is small (8–15 cm long), weighing 0.25–0.5 kg. The skin is dark green, even when ripe, with a sweet aroma and taste. The fruit is not as solid or dense as breadfruit and contains up to 15 rounded or obovoid, dark brown, shiny seeds (1.5 cm long) (Ragone, 2007).

Fig. 1.2. The tree (A) and fruit (B) of Artocarpus odoratissimus. Photographs courtesy of Dr N.J.C. Zerega.

Marang or terap (A. odoratissimus Blanco (1837)) trees are less cold tolerant than breadfruit and grow well in coastal areas where the temperature never goes below 7°C (Fig. 1.2A). It resembles both jackfruit and breadfruit in appearance. The fruits are round to oblong (Fig. 1.2B) and are regarded to superior to jackfruit and chempadak. The ripe fruit is light brown and succulent, weighs 1–3 kg and contains 60–200 seeds (bin Osman, 1993). The fruit is said to have a finer and more delicate flavour than jackfruit. The seeds are eaten roasted or boiled. Young fruits are also cooked.

A. elasticus Reinw. ex Blume (1825) is native to Burma, Thailand, Malaysia, Brunei, Indonesia and the Philippines. The yellowish-brown syncarp is oblong, with long flexible spines. The fleshy perianths are whitish in colour and sweet, and have a strong aroma. The seeds are edible on roasting. It is mostly used to provide barkcloth and timber.

A. chama Buch.-Ham. (1826) (synonym: A. chaplasha Roxb. (1832)) is native to north-eastern India, lower Burma, and the Andaman and Nicobar Islands. It is an important timber in India; its leaves are also used for elephant fodder.

Artocarpus hirsutus Lam. (1789), from India, is a tall evergreen tree reaching up to 50 m in height with a girth of 5 m or more, with a straight clean stem and dense foliage. The fruits are ovoid (Fig. 1.3), developing an orange hue when mature. The tree is valued for its timber and its wood is also used for furniture. The leaves are used as fodder for elephants, goats, etc.

Artocarpus lakoocha Roxb is known as monkey jack, lokhat and tampang. The tree grows 6–9 m tall with deciduous, large, leathery leaves. It is a native of the sub-Himalayan regions of India up to 1200 m and also Malaysia and Sri Lanka. The fruits are round or irregular (Fig. 1.4), 5–12 cm diameter, velvety, and dull yellow tinged with pink. The sweet–sour pulp is eaten raw or made into curries and chutney. The wood is hard and is used in the preparation of boats and furniture.

Fig. 1.3. Artocarpus hirsutus fruit. Photograph courtesy of Dr G. Karunakaran.

A. rigidus Blume is distributed in the lowland forests of India, Myanmar and Malaysia, and in Sumatra, Kalimantan and Java in Indonesia where it is cultivated in homestead gardens. It is a tall tree of 30–35 m in height with a dense, dark green, spreading crown (Fig. 1.5A). The fruits are roundish, 7.5–12.5 cm diameter, and greenish-yellow becoming dull yellow (Fig. 1.5B). The pulp is yellow and has a sweet, pleasant flavour. The seeds are covered by the waxy pulp and are roasted and eaten in many parts of tropical Asia. The wood is yellow to orange-red, fairly heavy, durable and resistant to termites, and is used in making furniture, native boats and houses.

Many other species are used for their timber, latex or fruit. They include:

•Artocarpus anisophyllus Miq. (1861) (Malaysia, Sumatra, Borneo);

•Artocarpus kemando Miq. (1861) (Malaysia, Sumatra, Borneo);

•Artocarpus lanceifolius Roxb. (1832) (Thailand, Malaysia, Sumatra, Bangka, the Riau and Lingga Archipelago, and Borneo);

•Artocarpus lowii King (1888) (Malaysia, Sumatra);

•Artocarpus maingayi King (1888) (Malaysia, Sumatra);

•Artocarpus sarawakensis F.M. Jarrett (1975) (Malaysia);

•Artocarpus scortechinii King (1888) (Malaysia, Sumatra and the Lingga Archipelago);

•Artocarpus sepicanus Diels (1935) (New Guinea);

•Artocarpus sericicarpus F.M. Jarrett (1959) (Philippines, Borneo, Sulawesi and the Moluccas);

•Artocarpus tamarin Becc. (1902) (Borneo);

•Artocarpus teysmannii Miq. (1861) (Nicobar Islands, Malaysia, Sumatra, Borneo, Sulawesi, the Moluccas and New Guinea); and

•Artocarpus treculianus Elmer (1909) (Philippines).

Two kinds of timber are distinguished: terap, a light-weight wood, and keledang, a medium-weight wood.

Fig. 1.4. Artocarpus lacucha fruit. Photograph courtesy of Dr G. Karunakaran.

Fig. 1.5. The tree (A) and fruit (B) of Artocarpus rigidus. Photographs courtesy of Dr N.J.C. Zerega.

1.6.3 Subgenus Prainea (King) Zerega, Supardi & Motley (2010)

The hard and heavy wood of members of the subgenus Prainea is used for posts and beams in house and bridge building. The fleshy perianth surrounding the fruit is edible. Three species are known:

•Artocarpus frutescens (Becc.) Renner (1907) (Sarawak, Kalimantan);

•Artocarpus limpato Miq. (1861) (Malaysia, Sumatra and Borneo); and

•Artocarpus papuanus (Becc.) Renner (1907) (Moluccas and New Guinea).

1.6.4 Subgenus Pseudojaca Trécul (1847)

Some species are mostly known for their fruits:

•Artocarpus nitidus Trécul (1847) (extends to southern China, Indo-China, Thailand, Malaysia, Borneo, Sumatra and Philippines). It includes four subspecies, with subspecies Lingnanensis being cultivated in Vietnam.

•Artocarpus lacucha (lakoocha ) Buch.-Ham. (1826) (south of Himalayas);

•Artocarpus tomentosulus F.M. Jarrett (1960) (Malaysia, Indonesia);

•Artocarpus tonkinensis A. Chev. (1918) (China, Vietnam, Cambodia); and

•Artocarpus vrieseanus Miq. (1867) (Philippines, Sulawesi, Moluccas, New Guinea, Bismarck Archipelago, Japan, Salawati, Aru Island, Louisiade Archipelago, Solomon Islands).

Other species are used for timber:

•Artocarpus altissimus (Miq.) J.J. Sm. (1907) (Sumatra, West Kalimantan);

•Artocarpus dadah Miq. (1861) (Burma, Thailand, Malaysia, Sumatra and Borneo);

•Artocarpus fretessii Teijsm. & Binn. ex Hassk. (1866) (Philippines, Sulawesi, Moluccas, Irian Jaya);

•Artocarpus fulvicortex F.M. Jarrett (1960) (Indonesia, Malaysia);

•Artocarpus glaucus Blume (1825) (Malaysia, Sumatra, Borneo, Java, Lesser Sunda Islands);

•Artocarpus gomezianus Wall. ex Trécul (1847) (Burma, Thailand, Indo-China, Malaysia, Sumatra, Java, Philippines);

•Artocarpus hypargyreus Hance ex Benth. (1861) (East Asia, South China);

•Artocarpus ovatus Blanco (1837) (Philippines);

•Artocarpus rubrovenius Warb. (1904) (Philippines); and

•Artocarpus subrotundifolius Elmer (1908) (Philippines).

1.6.5 Subgenus Cauliflori (F.M. Jarrett) Zerega (2010)

This subgenus contains only two related species, A. heterophyllus (see section 1.7) and Artocarpus integer.

Artocarpus integer (Thunb.) Merr. (1917) has the following synonyms:

•Radermachia integra Thunb. (1776);

•Polyphema champeden Lour. (1790);

•Artocarpus integrifolia L.f. (1781) non Trimen (1898); and

•Artocarpus champeden (Lour.) Stokes (1812).

It is commonly known as chempedak (cempedak in Indonesian) and is widely distributed in Burma (Tenasserim), Peninsular Thailand, Peninsular Malaysia, the Lingga Archipelago, Sumatra, Borneo, Sulawesi, the Moluccas and Irian Jaya. It is also cultivated in these areas as well as in western Java. It is an important crop in Malaysia and is also popularly cultivated in southern Thailand and parts of Indonesia, but is underutilized elsewhere (Wang et al., 2018).

Chempedak is similar to jackfruit but has smaller and narrower fruits (Fig. 1.6B) with a thinner rind and more juicy flesh, and is darker yellow or orange when ripe. It also has a characteristic aroma when ripe, described as both harsh and penetrating like durian (Durio zibethinus L.) and musky sweet like overripe jackfruit (Corner, 1938). The starchy seeds are also edible when cooked. Young plants bear scattered, reddish, wiry hairs on the leaves, and twigs and the mature plants usually are smaller than the jackfruit trees (Fig. 1.6A).

Chempedak’s putative wild relative was first described by Corner (1938) as Artocarpus integer (Thunb). Merr. var. silvestris Corner, commonly known as bangkong. Bangkong is most commonly found from primary and secondary lowlands to montane forests of Peninsular Malaysia, although it has been recorded in Sumatra, Lingga Archipelago, and south/south-east Borneo (Jarrett, 1959a; Kochummen, 1978; Turner, 1995). Wang et al. (2018) stated that chempedak and bangkong are sister taxa and distinct genetically and morphologically, but the direction of domestication origin is unclear. Genetic diversity is generally higher in bangkong than in chempedak.

Fig. 1.6. The tree (A) and chempedak fruit (B) of Artocarpus integer. Photographs courtesy of Dr G. Karunakaran.

Some hybrids between chempedak and jackfruit are known, called ‘nangka-chempedak’ in Malaysia. One of these has been cloned and named ‘CH/NA’.

1.7 The Jackfruit, Artocarpus heterophyllus

1.7.1 Nomenclature

Artocarpus heterophyllus Lam. (1789) (‘heterophylla’) has the following synonyms:

•Sitodium cauliflorum Gaertn. (1788)

•Artocarpus philippensis Lam. (1789)

•Artocarpus nanca Noronha (1790), nom. inval.

•Polyphema jaca Lour. (1790)

•Artocarpus brasiliensis Gomes (1803)

•Arctocarpus maxima Blanco (1837)

•Saccus heterophyllus (Lam.) Kuntze (1891)

According to Art. 62.2 of the International Code of Nomenclature for algae, fungi and plants (Shenzhen Code, 2017), all names ending in - carpus are treated as masculine. Hence, it is A. heterophyllus and not A. heterophylla.

Artocarpus integrifolius L.f. (1782) is often but erroneously used as the correct name; it is a synonym for Artocarpus integer (Thunb.) Merr. (1917).

The etymology of heterophyllus comes from Greek τερος (heteros), meaning ‘other, different’, and φρλλον (phullon) meaning ‘leaf’. Thus, the meaning is ‘which exhibits different leaves’.

1.7.2 History

The first Westerner to observe jackfruit was Ibn Battuta, who travelled in India in 1333. He said that ‘shaki and barki are the best fruits of India. This name is given to long-lasting trees; their leaves are like those of walnuts and their fruits are born on the trunk of the tree itself. Those near the soil form barki; their sweetness is greater and their taste more aggregable than shaki. Those to be found above are called shaki, the fruit of which is similar to big bottle gourds and the bark like an ox skin. When it has become yellow, in autumn, it is collected, cut up, and one to two hundred seeds are to be found in each fruit, like gherkins (Cucumis sativus). When this kernel is roasted or boiled, it tastes like broad beans’ (Samuel Lee/Ibn Battuta, 2005). In fact, the names cited by Ibn Battuta represent two cultivar groups distinguished in southern India, chakka, which has a soft and sweet pulp, and barka or varaka, which has a firm and tasty pulp.

Later on, one of the first Europeans who described jackfruit was the traveller Jean de Marignolli (Yule, 1350):

There is again another wonderful tree called Chake-baruhe, as big as an oak. Its fruit is produced from the trunk and not from the branches, and is something marvellous to see, being as big as a great lamb, or a child of three years old. It has a hard rind like that of our pine-cones, so that you have to cut it open with an axe; inside it has a pulp of surpassing flavour, with the sweetness of honey and of the best Italian melon; and this also contains some five hundred chestnuts of like flavour, which are capital eating when roasted.

The Portuguese were the first Europeans to become established in southern India, and spread the knowledge of jackfruit to Europe. The name jaca appears in Portuguese in 1535, and Garcia da Orta describes the fruit in his Coloquios dos simples (1563) (Dalgado, 1919–1921). The name was further borrowed by the French (jaca in 1553, and jaque in 1611) (Arveiller, 1963) and English (jaca in 1613, later jacq, and then jack fruit in 1830) as described in the Oxford English Dictionary.

The first illustrations of jackfruit were in 1656 by Michał Boym in his book Flora Sinensis and Jan Nieuhof (1665) in his Description Générale de la Chine. A better description and illustration can be found in the Hortus Malabaricus of Rheede tot Drakenstein (1678–1703), who gives the Malayalam name tsjaka-maram, where tsjaca is chakka in the Dutch spelling, and maram means ‘tree’.

The first part of the Malayalam name is supposed to come from Proto-Dravidian k

a

(y), meaning ‘fruit’, but there are many other names in India, such as panasa or phanas, and kanthal. In the Malay area, it is called nangka. All these different names show that the use and cultivation of jackfruit is very old. It is thought that jackfruit originated in India, but it must have spread very early to South-east Asia.

Jackfruit spread to China in the 16th century, and to South America in the 18th, but has never gained popularity outside southern Asia.

1.7.3 Description

Jackfruit is an evergreen, monoecious tree up to 20–30 m tall and 80–200 cm in diameter. All living parts exude a viscid, white latex when injured. The bark is rough to somewhat scaly, and dark grey to greyish-brown. The crown is dense, conical in young and shaded trees, becoming rounded or spreading in the older tree (Fig. 1.7A). New shoots, twigs and leaves are usually glabrous but occasionally short-haired and scabrid. The stipules are ovate–acute, 1.5–8 cm × 0.5–3 cm, deciduous and leaving annular scars on the twigs.

Fig. 1.7. The tree (A) and fruit (B) of Artocarpus heterophyllus. Photographs courtesy of Dr G. Karunakaran.

The leaves are thin, leathery, obovate–elliptic to elliptic, 5–25 cm × 3.5–12 cm, broadest at or above the middle, the base cuneate, with the margin entire or in young plants often with one to two pairs of lobes; the apex is rounded or blunt with a short, pointed tip. The leaves are dark green and shiny above, dull pale green underneath, and the petiole is 1.5–4 cm long, shallowly grooved on the adaxial side, and sparsely hairy. The leaves are inserted alternately on horizontal branches but tend to be spiral on ascending branches with a 2/5 phyllotaxy. The stipules are present, ovate, about (1.5–)4(–8) cm long and (0.5–)1(–3) cm wide, deciduous noticeable scars on the stem.

The inflorescences are solitary and borne axillary on special lateral, short leafy shoots arising from older branches and the main trunk; the male flower heads are barrel-shaped or ellipsoid, 3–8 cm long and 1–3 cm across, composed of sterile and fertile flowers closely embedded on a central core (receptacle), dark green, with a stalk 1.5–3.5 cm long and 0.5–1 cm wide, bearing an annular ring near the distal end. Sterile male flowers have a solid perianth, while fertile male flowers have a tubular, bilobed, 1–1.5 mm long perianth, with stamens 1–2 mm long. Female heads are borne singly or in pairs distal to the position of the male heads, and are cylindrical or oblong, dark green, 5–15 cm long and 3–4.5 cm wide, with a distinct annulus at the top end of the stout stalk, subtended by a spathaceous, deciduous bract, 5–8 cm long; female flowers have tubular perianths, which are fused at both ends and projecting as three to seven angled, blunt or pointed, minute pyramidal protuberances topped by spathulate or ligulate styles and stigmas.

Female flowers have a tabular perianth of free segments when young but fusing in the mid-point; the perianth encloses a basal compressed ovary with an obliquely inserted terminal style with a club-shaped stigma. The stigmatic points are persistently sharp (becoming blunt in mature fruits). The stigmas protrude after 4–6 days of opening of the spathes. The female spikes become woolly with numerous stigmas within another 4–6 days. The receptivity of the stigma remains for 28–36 days (Sambamurthy and Ramalingam, 1954; Azad, 1989).

Moncur (1985) suggested a pollination mechanism that may involve the interplay of both wind and insect vectors in which the activity of insects on the male inflorescences may promote pollen release, with subsequent transportation by wind or gravity. However, Pushpakumara (2006) suggested that wind is primarily responsible for the pollination of A. heterophyllus and this is supported by the observations of the deposition of pollen grains on pollen traps and pollen grains and/or grains with pollen tubes counted on open-pollinated stigmas. Gardner et al. (2018) stated that jackfruit is thought to be pollinated by a gall midge, Clinodiplosis ultracrepidata (Diptera: Cecidomyiidae).

The fruit is a syncarp, barrel- or pear-shaped, 30–100 × 25–50 cm, with short pyramidal protuberances or warts; the stalk is 5–10 cm long, 1–1.5 cm wide; the rind is approximately 1 cm thick, together with the central core (receptacle) inseparable from the waxy, firm or soft, golden-yellow, fleshy perianths surrounding the seeds.

The seeds are numerous (100–500 per fruit), oblong–ellipsoid, 2–4 × 1.5–2.5 cm in size and 2.5–14 g in weight, enclosed by a horny endocarp and subgelatinous exocarp. The testa are thin and leathery. The embryo has a ventral radicle and fleshy cotyledons that are unequal (the smaller one being one-third to one-half of the larger). The endosperm is very small or absent (Wealth of India, 1985; Morton, 1987; Soepadmo, 1991; Campbell and Ledesma, 2003; Simon et al., 2007; Prakash et al., 2009; Witherup et al., 2019).

1.7.4 Distribution around the world

Jackfruit originated in the rainforest of the Western Ghats of India. Archaeological findings in India have revealed that jackfruit was cultivated in India 3000–6000 years ago. Findings also indicate that Indian Emperor Ashoka the Great (274–237 BC) encouraged arbori-horticulture of various fruits including jackfruit. It then spread its cultivation to neighbouring South and South-east Asian countries and to southern China (Haq, 2006).

Jackfruit is believed to have been introduced to the Philippines during the 12th century AD, when the coastal Filipinos started to trade with India, Malaysia and China (Pelzer, 1948). Jackfruit is now widely grown in many Asian countries especially India, Bangladesh, Myanmar, Nepal, Sri Lanka, Thailand, Malaysia, Indonesia and the Philippines. It is also grown in southern China and in the Indo-Chinese region in Laos, Cambodia and Vietnam. From Asia, it spread to tropical Africa, especially the eastern part: Zanzibar, Kenya, Uganda and Madagascar (Haq, 2006). Jackfruit spread further to tropical and subtropical America (Brazil, Surinam, Caribbean and USA) and Australia between the mid-17th and late 19th century.

India is the largest producer of jackfruit in the world producing 183,000 t of fruit in 2017–2018. The major producing states are Assam, Tripura, West Bengal, Kerala, Arunachal Pradesh, Tamil Nadu, Karnataka and Jharkhand. It is widely grown in the homesteads in most of the states, with very few commercial orchards.

Jackfruit is considered the national fruit of Bangladesh and is one of the most widely distributed and cultivated crops in this country. Major jackfruit-growing areas are the former districts of Dhaka, Mymensingh, Sylhet, Rajshahi, Dinajpur and Chittagong. In most rural areas, the jackfruit plant is grown in the homestead.

In China, jackfruit is grown over about 12,000 ha of which more than 60% is in Hainan province. Oher relatively small growing areas are the Guangdong, Guangxi, Yunnan, Sichuan and Fujian Provinces.

In Thailand, jackfruit is grown mostly as a backyard plant and in mixed fruit orchards, mostly in the east and south of the country. The total area under jackfruit cultivation increased from 7140 ha in 2005 to 8951 ha in 2020. Jackfruit is locally known as ‘Khanun’ in Thailand.

Jackfruit is widespread in Vietnam but is grown mainly in the south. The area under jackfruit cultivation has increased rapidly during the past 5 years, with an average growth of 20% year–1 from 2016. The total area planted to jackfruit is about 59,705 ha, excluding jackfruit trees grown as a backyard tree, with an annual production of 550,000 t in 2020. The Mekong Delta is known as the top jackfruit-producing area in Vietnam. The total cultivation is 30,045 ha and contributes about 50% of its share to the country. After the Mekong Delta, the south-east region and central highland rank as the second and third largest producers with an estimated acreage of 12,597 ha and 5312 ha, respectively, in 2020. The top five jackfruit-producing provinces in Vietnam are Tien Giang (13,141 ha), Dong Nai (7645 ha), Hau Giang (6966 ha), Dong Thap (2692 ha) and Dak Lak (2081 ha) (General Statistics Office, 2021). The area under cultivation of jackfruit reached an estimated 72,200 ha in 2021.

Most jackfruit produced in Vietnam is exported, and only a small percentage is consumed locally. The rate of processed jackfruit is estimated to be not more than 10% of the production output, and a small percentage is frozen pulp. The main processing product is jackfruit dried slices/chips. The export value of jackfruit has increased continuously in recent years, from more than US$61 million in 2016 to more than US$99.8 million in 2019 and not less than UD$138.1 million in 2020. China was the largest export market for Vietnamese jackfruit, accounting for more than 94% in 2018, 86% in 2019 and nearly 96% in 2020 (Anon, 2021b). Jackfruit is also exported to many other markets such as the Philippines, Papua New Guinea, Canada and Australia.

European colonists, perhaps the Portuguese and later the British, introduced jackfruit into Malaysia from southern India. It is locally known as ‘nangka’, ‘tsjaka’ and ‘jaka’. The main jackfruit-growing areas in Malaysia are Johor, Sarawak, Sabah, Kelantan and Kedah. The area planted with jackfruit in Malaysia in 2020 was 4675 ha with production of 35,624 t of fruit. Malaysia exports jackfruit to the Middle East, Europe, China, Australia, Hong Kong and Singapore.

Jackfruit is thought to have been introduced in the Philippines in 12th century AD and is now widely grown. The major growing regions are Cagayan Valley, Calabarzon, Bicol, Western Visayas, Central Visayas, Eastern Visayas, Zamboanga Peninsula, Northern Mindanao and Davao Region. Jackfruit is known locally by many names such as ‘langka’, ‘nangka’, ‘ananka’, ‘yanka’, ubiyen’, ‘badak’ and ‘sagakat’. However, the area and production of cultivated jackfruit in the Philippines has been decreasing since 2012. The total planted area in 2012 was 14.42 thousand ha, which decreased to 13.81 thousand ha in 2021.

Indonesia introduced jackfruit from India and it is now grown in Java, Sumatra, Bali, Nusa Tenggara, Kalimantan, Sulawesi, Maliku and Papua. It is mostly grown as backyard trees and in mixed fruit orchards. There are several local names of jackfruit in Indonesian regions such as ‘panch’, ‘nongko’, ‘langgae’, ‘anane’, ‘sibodak’, ‘naka’, ‘baduh’, ‘binaso’, ‘malasa’ and ‘kuloh’. The combined production of jackfruit and chempadak increased from 537,186 t in 2002 to 824,068 t in 2020.

Tropical exotic fruits including jackfruit were introduced into northern Australia as early as the late 1800s. In northern Australia, about 9300 jackfruit trees were recorded in 2012.

Jackfruit was reported in Hawaii prior to 1888. It is not widely cultivated in the USA but may be found in south Florida and Hawaii.

In Israel, jackfruit was introduced in the 1930s. The trees bore fruit for several seasons but eventually died. The fresh fruit is not marketed in Israel (Avner Galili, Juran Technologies, Israel, personal communication).

There is very little commercial production of jackfruit in Taiwan. It is grown mostly in backyards or private orchards for personal consumption. Most local jackfruit is used for fried fruit, while dry processed fruits are imported from Vietnam,