Trichosanthes (PROSEA Vegetables)

Plant Resources of South-East Asia Introduction

List of species

Trichosanthes L.

Protologue: Sp. pl.: 1008 (1753); Gen. pl. ed. 5: 439 (1754).

Family: Cucurbitaceae

Chromosome number: x= 11; 2n= 22 (T. cucumerina)

Major species and synonyms

• Trichosanthes celebica Cogn., Monogr. phan. 3: 385 (1881).

• Trichosanthes cucumerina L., Sp. pl.: 1008 (1753), synonyms: T. anguina L. (1753), T. cucumerina L. var. anguina (L.) Haines (1922).

• Trichosanthes ovigera Blume, Bijdr.: 934 (1826), synonyms: T. cucumeroides (Seringe) Maxim. (1875), T. himalensis C.B. Clarke (1879).

• Trichosanthes villosa Blume, Bijdr.: 934 (1826), synonym: T. kerrii Craib (1914).

Vernacular names

T. celebica

• Indonesia: tawuruk, amut tamburuk (Sulawesi)
• Malaysia: akar tiga chabang, chabang tiga, mentimun dendang (Peninsular).

T. cucumerina

• Snake gourd (En)
• Serpent végétal (Fr)
• Indonesia: paria belut, paria ular, pare welut (Javanese)
• Malaysia: ketola ular, timun bengkok, petola ular (Peninsular)
• Philippines: pakupis, tabubok (Tagalog)
• Laos: ngoo ngèèwz
• Thailand: buap ngu, nom phichit (central), ma noi (northern)
• Vietnam: dây na tây, dưa núi, mướp tây.

T. ovigera

• Indonesia: areuj tiwuk (Sundanese)
• Vietnam: hoa bát.

T. villosa

• Indonesia: areuj baduyut, waluh leuweung (Sundanese)
• Philippines: kandolamo (Bukidnon)
• Laos: cho' tau quân
• Vietnam: dây dỏ mỏ

Origin and geographic distribution

The genus Trichosanthes is native to southern and eastern Asia, including South-East Asia, and to Australia and the western Pacific. Although the genus is poorly known taxonomically, it is thought to comprise about 40 species, about 15 of which are present in South-East Asia.

• T. celebica is only known wild from Peninsular Malaysia and Sulawesi.

• T. cucumerina occurs wild in the whole area of the genus and in the same area it is also of ancient cultivation. Its domestication may have started in India. Only occasionally is it cultivated in other tropical or subtropical areas. As vegetable it is the most important Trichosanthes species.

• T. ovigera occurs wild in the whole area of the genus but is probably most important in China and Japan. It is possibly also cultivated occasionally.

• T. villosa occurs wild in Java, the Philippines, Thailand and Indo-China.

Uses

• T. celebica. Leaves are eaten cooked as a vegetable. They are also used as a substitute for soap and when smeared on the skin are reputed to repel mosquitoes.

• T. cucumerina. Immature fruits of cultivated forms are eaten boiled as a vegetable or in curries. Young shoots and leaves are also edible. In some forms, all young parts have an unpleasant smell and taste bitter but these characteristics disappear after boiling. The fruits become inedible upon ripening: they taste bitter and develop hardened fibrovascular bundles like the loofahs. In West Africa the red fruit pulp is used as a kind of cheap tomato paste. Fruits of the wild forms are very bitter and inedible. They are used in traditional medicine as a purgative and vermifuge. A kind of cough syrup is prepared from the pulp.

• T. ovigera. Boiled fruits are eaten as a side-dish with rice. In China and Japan the starch of the tubers is sometimes extracted.

• T. villosa. Young fruits are eaten boiled as a vegetable. Sap from the leaves is used to cure dysentery; pounded leaves are applied on the body to reduce fever and alleviate the pain of swollen legs.

Production and international trade

Snake gourd is mainly grown as a home garden crop for own consumption or for the local market. No statistics are available. The wild edible species are collected and consumed locally only.

Properties

The edible part of the immature fruits of snake gourd is 86-98%. Per 100 g edible portion it contains: water 94 g, protein 0.6 g, fat 0.3 g, carbohydrates 4 g, fibre 0.8 g, Ca 26 mg, Fe 0.3 mg, P 20 mg, vitamin A 235 IU, vitamin B₁ 0.02 mg, vitamin B₂ 0.03 mg, niacin 0.3 mg, vitamin C 12 mg. The energy value is approximately 70 kJ/100 g.

All species produce the purgative glucoside elaterin in their tissues, the amount of which increases as the fruit ripens. Seed oils of Trichosanthes species consistently have major proportions of punicic acid.

Description

• Annual or perennial, monoecious or dioecious, climbing or trailing herbs. Tendrils simple or 2-5-fid.
• Leaves alternate, simple, unlobed or palmately 3-9-lobed or compound.
• Male flowers in axillary racemes, rarely solitary; calyx tubular, 5-lobed; corolla 5-lobed, the lobes fringed with hairlike outgrowths, usually white; stamens 3, anthers free or united, 2 bilocular, 1 unilocular.
• Female flowers solitary; perianth as in male flowers; stigmas 3, entire or bifid.
• Fruit a fleshy, indehiscent berry (pepo), containing numerous seeds.
• Seed generally flattened.

T. celebica

• Leaves coriaceous, trifoliolate; petiole 2-3 cm long; leaflets unequal, mid-one largest, ovate-oblong, 7-12 cm × 3.5-6 cm.
• Fruit ovoid to oblongoid, 10-15 cm × 7-8 cm, red.
• Seed brown with thick margin.

T. cucumerina

• Monoecious annual with 5-angled, furrowed, slender stem. Tendrils 2-3-branched.
• Leaves simple, more or less deeply 5-7-lobed or angular, 7-25 cm × 8-20 cm, cordate at base, margins dentate, pubescent; petiole 2-10 cm long, furrowed, succulent, scabrid hairy.
• Male flowers on 10-30 cm long peduncles, 5 to many flowers together.
• Female flowers sessile.
• Fruit very slender, long cylindrical, often twisted, 30-180 cm × 2-10 cm, much smaller in wild forms, greenish-white when immature, dark red when mature.
• Seed thick, 1-1.5 cm long, brown, sculptured, margin undulate.

T. ovigera

• Dioecious perennial herb with tuberous roots. Tendrils 2-branched.
• Leaf-blade broadly ovate to suborbicular, 7-15 cm × 6-15 cm, unlobed to deeply 3-5-lobed, scabrid above, pubescent beneath; petiole 2-6 cm long.
• Male flowers in 4-12-flowered racemes 6-20 cm long; peduncle 3-10 cm long with dentate, obovate, 5-10 mm long bracts; pedicel 0.5-2 cm long.
• Female flowers on 2-3 cm long pedicel.
• Fruit ovoid to ellipsoidal, 8-10 cm × 2.5-3 cm, red when mature.
• Seed 3-locular, 6-8 mm long, grooved, brown.

T. villosa

• Dioecious herb with angular stem. Tendrils 3-5-branched.
• Leaf-blade ovate-orbicular, 10-16 cm × 5-18 cm, entire or acutely 3-lobed, pubescent above, densely soft hairy beneath; petiole 6-8 cm long.
• Male flowers in 10-20 cm long racemes; bracts entire, 3-4 cm × 1-1.5 cm; pedicel 2-3 cm long.
• Female flowers on 1.5 cm long pedicel.
• Fruit ellipsoid-globose, 8-13(-30) cm in diameter, yellow to red at maturity, fruit stalk robust.
• Seed flattened obovoid, about 2 cm × 1 cm × 0.5 cm.

Growth and development

Flowering of snake gourd starts about 5 weeks after planting; the male flowers appear first, followed by the female flowers about 3 days later. The flowers open in the evening or in the early morning. Anthers dehisce several hours before anthesis, stigmas are receptive from a few hours before anthesis to a few hours after. Pollination is effected by insects. In early-maturing cultivars the first young fruits are harvestable about 7 weeks after planting, and picking may be continued for 1-2 months.

Other botanical information

The genus Trichosanthes is poorly known and needs a thorough taxonomical revision. The snake gourd has been considered a separate species (T. anguina); now it is believed to be a cultivated form of T. cucumerina which can best be classified as a cultivar group (e.g. cv. group Snake Gourd) consisting of several cultivars. The traditional botanical classification of the cultivated and wild forms in different varieties (T. cucumerina L. var. anguina (L.) Haines and var. cucumerina respectively) or subspecies (ssp. anguina (L.) Grebenscikov and ssp. cucumerina) must be rejected.

Ecology

Snake gourd is well adapted to the humid tropical lowlands. It does not tolerate dry soil and requires a good moisture reserve in the soil, but it is also sensitive to waterlogging. The optimum average temperature for growth is 30-35 °C, with a minimum of 20 °C.

The wild species can be found in scrub, along forest edges and in open forest, up to 1000(-1500) m altitude.

Propagation and planting

Snake gourd is propagated by seed, requiring 4-6 kg/ha. Seed can be sown in a nursery and transplanted at the 2-true-leaf stage but usually it is sown in situ in planting holes or on ridges 1-1.5 m apart, 60-75 cm between plants.

Husbandry

Snake gourd plants require support from poles or a trellis (in home gardens the plants are often trailed over thatched huts or over walls) so that the fruits can hang vertically. A weight is usually hung onto the tip of the growing fruit to keep it straight. Usually the crop receives little attention. Response to manuring and fertilizer application is good, but if too much nitrogen is applied vine growth is excessive. Female to male flower ratio can be improved by pruning. In seasonal climates frequent irrigation may be necessary during the dry season.

Diseases and pests

The most serious diseases of snake gourd are downy mildew (Pseudoperonospora cubensis) and anthracnose (Colletotrichum lagenarium). Repeated spraying with fungicides, e.g. maneb, can control both diseases.

The major pests of snake gourd are leaf beetles (Aulacophora vinula, Copa occidentalis and Lagria villosa) and root knot nematodes (Meloidogyne).

Harvesting

Snake gourds are picked 12-20 days after fruit set. The fruits should be harvested when they are about 30-60 cm long, green and tender. For seed production fruits are harvested when they are fully ripe and have attained full size; only straight fruits with perfect form are selected.

Yield

Single snake gourd fruits weigh 0.5-1 kg. Per plant 6-10 fruits can be harvested from traditional cultivars, and up to 50 fruits from improved cultivars. Total yield varies from 8-10 t/ha.

Handling after harvest

Snake gourds are very succulent and do not keep well. They can be stored for 10-14 days at a temperature of 16-17°C at a relative humidity of 85-90%.

Genetic resources

Germplasm collections of snake gourd are available in the Philippines (NPGRL-IPB, Los Baños), India (Kerala Agricultural University, Trichur, Kerala), Nigeria (NACGRAB, Ibadan), Russia (the Vavilov Institute of Plant Industries, Petersburg) and the United States (Department of Horticultural Sciences, Cornell University, New York).

Breeding

Priority in breeding should be given to disease resistance and a high female to male flower ratio.

Prospects

Trichosanthes will remain a minor vegetable crop in South-East Asia. Adequate investigation of the wild species might reveal desirable characteristics of interest to improve snake gourd or lead to domestication of other species with edible parts.

Literature

• Bates, D.M., Robinson, R.W. & Jeffrey, C. (Editors), 1990. Biology and utilization of the Cucurbitaceae. Comstock, Cornell University Press, Syracuse, New York, United States. 485 pp.
• Butani, D.K. & Verma, S., 1977. Pests of vegetables and their control. Chapter 11(3). Cucurbits. Indian Agricultural Research Institute (IARI), New Delhi, India. pp. 37-41.
• Deshpande, A.A., Bankapur, V.M. & Venkatasubbaiah, K.A., 1980. Studies on floral biology of snake gourd (Trichosanthes anguina L.) and ash gourd (Benincasa hispida (Thunb.) Cogn.). Mysore Journal of Agricultural Science 14: 8-10.
• Herklots, G.A.C., 1972. Vegetables in South-East Asia. George Allen & Unwin, London, United Kingdom. pp. 346-349.
• Keraudren-Aymonin, M., 1975. Cucurbitacées. Trichosanthes. In: Flore du Cambodge, du Laos et du Vietnam [Flora of Cambodia, Laos and Vietnam]. Vol. 15. Muséum National d'Histoire Naturelle, Laboratoire de Phanérogamie, Paris, France. pp. 75-92.
• Seshadri, V.S., 1986. Cucurbits. In: Bose, T.K. & Som, M.G. (Editors): Vegetable crops in India. Naya Prokash Press, Calcutta, India. pp. 91-164.

Authors

• B.H. Gildemacher, G.J. Jansen & K. Chayamarit