1548

2: Edible fruits and nuts

Syzygium cumini (L.) Skeels

USDA Bur. Pl. Industr. Bull. 248: 25 (1912).

MYRTACEAE

2n = variously recorded as 22, 42—44, 44, 66.

Myrtus cumini L. (1753), Eugenia jambolana Lamk (1789), Syzygium jambolanum (Lamk) DC. (1828), Eugenia cumini (L.) Druce (1914).

Jambolan (En), jamélongue (Fr). Indonesia: jamblang, duwet (Java). Malaysia: jambulana, jambulan. Philippines: duhat (Tagalog, Bisaya), lomboi (Ilokano). Burma: thabyay-hpyoo. Cambodia: pring bai. Laos: va. Thailand: wa (central), hakhiphae (Chiang Rai). Vietnam: vôi rung, trâm môc.

Jambolan is native to the subtropical Himalayas, India, Sri Lanka, Malesia and Australia, where it is also widely cultivated. At present it is grown throughout the tropics and subtropics.

The ripe fruit is usually eaten fresh. It tastes subacid and rather astringent. It is common practice in the Philippines as well as in India to sprinkle the fruits with salt and shake them inside a covered bowl to soften them. They may also be made into juice, jelly or wine. Jambolan wine is produced in commercial quantity in the Philippines. Leaves may be used as fodder. The flowers have abundant nectar from which bees make a fine quality honey. The bark is an astringent and may be used as a gargle. It can also be used for dyeing. Powdered seed is helpful in treating diabetes, dysentery, diarrhoea and other ailments. In India the tree is grown to provide shade for coffee. It is wind-resistant and is sometimes closely planted in rows as a windbreak. The wood can be used as a fairly satisfactory fuel.

Jambolan is mainly a home garden fruit tree or grows wild in secondary forests. Fruit sold in local markets or used for processing comes mainly from these sources. Jambolan seeds used to be traded for medicinal use; they were exported from India to Malaysia and Polynesia, and from the West Indies to Europe.

Per 100 g edible portion the fruit contains: water 84—86 g, protein 0.2—0.7 g, fat 0.3 g, carbohydrates 14—16 g, fibre 0.3—0.9 g, ash 0.4—0.7, calcium 8—15 mg, phosphorus 15 mg, iron 1.2 mg, riboflavin 0.01 mg, niacin 0.3 mg, traces of vitamin A and thiamine, vitamin C 5—18 mg. The energy value averages 277 kJ/100 g.

An evergreen, stout tree, 10—20(—30) m tall, trunk 40—90 cm in diameter, low branching, crown irregular or globose, spreading 12 m; bark rough, dark grey on lower part of tree, further up smooth and light grey. Leaves opposite, broadly obovate-elliptic to elliptic-oblong, 5—25 cm x 2—10 cm, cuneate or rounded at base, apex blunt or tapering to a point, entire, edges thin transparent, thick coriaceous, pinkish when young, later shiny dark green above, faintly turpentine-scented when bruised; petiole 1—3.5 cm long. Inflorescences in panicles, usually borne on leafless branches, solitary or fascicled, dense, many-flowered, 5—12 cm long; flowers small and fragrant; calyx widely campanulate, 4—6 mm long, irregularly dentate above; disk yellow; petals 4, free, orbicular, greyish-white to pink; stamens numerous, 4—7 mm long, white; ovary 2—3-celled, style 6—7 mm long, white. Fruit an ovoid-oblong berry, often curved, crowned by the calyx lobes, 1—5 cm long, dark violet, in clusters up to 40; pulp grey-yellow to violet, juicy, almost inodorous, with sourish astringent taste. Seeds 0—5, oblong, up to 3.5 cm long, green to brown.

Seed germinates within the second week after sowing. The resulting seedling grows fast; it starts flowering 7—8 years later, at which stage it has a low-branched trunk and well-spread branches. Budded or grafted trees are more precocious and may start flowering in 3—4 years. The numerous inflorescences are produced mainly from the leaf axils of 5—12-month-old shoots; they may also be produced terminally or on leafless branches. Pollination is by bees and flies, but also by wind. In the Philippines the trees flower from January to March; the fruits ripen from the end of March until early June. In Java flowering occurs in July—August and the fruits ripen in September and October. Flower and fruit drop adjust the crop. Four weeks after full bloom about half the flowers and fruitlets may be shed, and there is some further loss of fruit right up to maturity. The tree continues to grow fast and may attain full size in about 40 years.

The jambolan is extremely variable in tree habit and fruit quality as well as season of fruiting. Seedling trees usually bear small, very sour and astringent fruits; improved selections may bear large, savoury, small-seeded fruits.
There are many cultivars. Usually the fruit colour is light purple to black-violet, but there are also white-fruited cultivars. Some cultivars are seedless, but in seedling populations 20—50% of the seeds are polyembryonic. Some named cultivars are: 'Early Wild', 'Late Wild'. 'Pharenda', 'Small Jaman', 'Dabka', 'Krian Duat' and 'Super Duhat'.

Jambolan grows best in the tropics at elevations up to 600 m, although it can be found as high as 1800 m. In the latter case it does not fruit but can be grown for its timber. It develops well in regions with over 1000 mm annual rainfall with a distinct dry season. Jambolan grows on river banks and can withstand prolonged flooding. It is drought-tolerant after its initial development. It also grows well in the warmer parts of the subtropics. In southern Florida (United States), mature trees may suffer from occasional frosts. Jambolan can thrive on a variety of soils in low, wet areas and on higher, well-drained land (loam, marl, sandy soils, calcareous soils).

Jambolan is generally propagated by seeds (which lose viability quickly), although superior cultivars can be propagated asexually by marcotting, inarching, grafting and budding. In marcotting, rooted branches may be separated within 90 days from girdling. Grafting and budding are employed for large-scale propagation. Cleft grafting, the method used in the Philippines, can be carried out any month, but up to 95% success is achieved if done in November to December. Budding can be done by the patch or shield method. Budded or grafted trees are planted at the onset of the rainy season at a suggested spacing of 8—10 m.

The trees need very little care and attention until they bear fruit. In India manure is applied after harvest. If trees do not bear satisfactorily they may be root-pruned or girdled.

No serious pests and diseases infest jambolan trees. Leaf-feeding caterpillars, white fly, scales, mealy bugs and fruit flies occasionally reach damaging levels.

Fruits do not all ripen at the same time. Ripe fruits turn dark purple or almost black in colour and drop to the ground. Fruit for home use may simply be gathered under the tree, but fruit for the market should be picked selectively. This is a tedious job as the tree has to be climbed to hand-pick mature fruit.

Yield varies considerably; prolific trees have been reported to yield as much as 100 kg per tree. Clonal trees remain smaller but may still produce 60—70 kg, which is quite a lot of fruit for the home gardener!

Fruits are sorted, discarding those that are damaged or off-size. They are immediately brought to the market and disposed of promptly as they are very perishable.

The large variations between seedling trees offer much room for collecting germplasm for immediate use as commercial cultivars or for breeding work. The existing cultivars have resulted from selection and cloning of superior trees.
There is a modest germplasm collection in Los Baños, the Philippines.

Jambolan is a popular seasonal fruit in South-East Asia. Difficulty of harvesting and the perishable nature of the fruit make it doubtful whether jambolan will become a commercial fruit crop in the future. Extension of the markets for processed products such as juice and wine may offer the best chances.

Bajpai, P.N. & Chaturvedi, O.P., 1985. Jamun [Jambolan]. In: Bose, T.K. (Editor): Fruits of India, tropical and subtropical. Naya Prakash, Calcutta. pp. 581—590.
Crisostomo, L. C., 1977. Preservation of fruits and vegetables. Laboratory Services Division, Bureau of Plant Industry, Manila. pp. 12, 42.
Lazo, F.O. & Batoon, M.P., 1962. A report on the occurrence of a superior strain of duhat, Syzygium cumini (Linn.) Skeels). Plant Industry Digest 22: 6—7.
Misra, R.S. & Bajpai, P.N., 1975. Studies on flower biology of jamun (Java plum) (Syzygium cumini (L.) Skeels). Indian Journal of Horticulture 32: 15—24.
Padolina, F., 1931. Vegetative propagation experiments and seed germination. Philippine Journal of Agriculture 2: 347—355.

R.E. Coronel

Coronel, R.E., 1991. Syzygium cumini (L.) Skeels. In: Verheij, E.W.M. and Coronel, R.E. (Editors): Plant Resources of South-East Asia No 2: Edible fruits and nuts. PROSEA Foundation, Bogor, Indonesia. Database record: prota4u.org/prosea