Vigna marina (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Vigna marina (Burm.) Merrill

Protologue: Interpr. Rumph. Herb. Amboin.: 285 (1917).

Family: Leguminosae - Papilionoideae

Chromosome number: 2n= 22

Synonyms

• Phaseolus marinus Burm. (1769),
• Dolichos luteus Swartz (1788),
• Vigna lutea (Swartz) A. Gray (1854).

Vernacular names

• Dune bean, sea bean (En). Notched cowpea (Am)
• Indonesia: kacang laut (Java), rerenge makenti (Sulawesi), fofuo dowongi (Ternate)
• Malaysia: kacang laut
• Philippines: pataning-dagat.

Origin and geographic distribution

The origin of V. marina is unknown. It is widely distributed pantropically along sea shores.

Uses

V. marina occurs as a natural sand binder on sea shores and coastal sand dunes. It is also cultivated as a cover crop. In the Maldives it is grown for its edible seeds, while in Australia its thicker roots are eaten after roasting. After thorough cooking, the leaves can be eaten as a vegetable. Livestock will eat the plant when cut as green forage.

Properties

The approximate composition of V. marina per 100 g fresh material is: water 66 g, protein 3 g, carbohydrates 24 g, fat 1 g, fibre 4 g, and ash 2 g.

Botany

• Prostrate or trailing, biennial or short-lived perennial herb up to several metres long. Stem subsucculent, glabrous or with a few scattered hairs, ribbed, rooting at the nodes.
• Leaves trifoliolate, succulent to membranaceous; stipules cordate, about 5 mm × 3 mm, persistent; petiole 5-11.5 cm long; rachis 1.5-3 cm long; petiolule about 0.5 cm long; stipels 2 mm long; leaflets rounded-obovate to oblong-ovate, 5-8.5(-9) cm × 5-8(-10) cm, often emarginate-mucronate at the apex, venation reticulate and raised, glabrous or with a few hairs on either surface.
• Inflorescence an axillary, erect raceme, 1.5-3 cm long; peduncle 4-7(-13) cm long, bearing 6-12 flowers at the top and between which extra-floral nectaries are present; pedicel 3-6 mm long.
• Flower yellow, 1.5-2 cm long; calyx tubular, tube 5.5-6.5 mm long, nearly glabrous, ending in 4 unequal teeth; standard of corolla obovate, 18-19 mm × 20-22.5 mm; stamens 10, diadelphous, 15-17 mm long; style bearded on the upperside and bearing a short beak beyond the stigma.
• Pod subcylindrical, 4-6 cm × 1 cm, straight or slightly curved, glabrous when old, strongly constricted between the 2-9 seeds, indehiscent, black.
• Seed subglobose to kidney-shaped, 4.5-6 mm in diameter, greyish-brown, with prominent yellowish hilum.

Nodulation occurs easily and profusely, probably with a wide range of Rhizobium strains. The coastal distribution seems related to the inflated, non-shattering pods, which may float from coast to coast.

For Africa, V. marina is subdivided into 2 subspecies: subsp. marina (as described here, occurring along the coast of the Indian Ocean, being similar to the form found in South-East Asia) and subsp. oblonga (Benth.) Padulosi (synonym: V. oblonga Benth.) (pods less inflated, seeds smaller, stems thinner, mainly occurring along the Atlantic coast). V. marina is often confused with the also pantropically occurring V. luteola (Jacq.) Bentham, from which it differs mainly in habitat. V. marina grows along sea shores, whereas V. luteola is found along freshwater shores. When crossed, the two species produce fertile hybrids.

Ecology

V. marina grows naturally in the vicinity of sandy or stony sea shores, often just above the high tide mark, in coastal lagoons and river mouths, and does not occur at much higher altitudes. It grows well on wet and poorly drained soils. At least 500 mm annual rainfall is required. It is very frost-sensitive and obviously salt-tolerant.

Agronomy

V. marina can easily be propagated by seed or cuttings. Per ha, 1-2 kg seed are needed. In Australia it has been tested in a 1:1 mixture with the grass Paspalum plicatulum Michaux. Its dry matter production was 3 t/ha containing 100 kg nitrogen. The grass yield was less than with other legumes such as Macroptilium atropurpureum (DC.) Urban.

Genetic resources and breeding

It is unlikely that any substantial germplasm collections of V. marina are being maintained. There are no known breeding programmes. Its adaptation to dry conditions and possible tolerance of salinity may be useful in breeding programmes of other Vigna species.

Prospects

V. marina is promising as a cover and forage crop especially for saline conditions, but more research is needed to optimize its use.

Literature

• Allen, O.N. & Allen, E.K., 1981. The Leguminosae: A source book of characteristics, uses and nodulation. Madison, Wisconsin, United States. pp. 682-687.
• Bogdan, A.V., 1977. Tropical pasture and fodder plants. Longman, London, United kingdom. p. 421.
• Jones, R.J., Davies, J.G. & Waite, R.B., 1967. Contribution of some tropical legumes to pasture yields of dry matter and nitrogen at Samford, Southeastern Queensland. Australian Journal of Experimental Agriculture and Animal Husbandry 7: 57-65.
• Maréchal, R., Mascherpa, J.-M. & Stainier F., 1978. Etude taxonomique d'un groupe complexe d'espèces des genres Phaseolus et Vigna (Papilionaceae) sur la base de données morphologiques et polliniques, traitées par l'analyse informatique [Taxonomic study of a complex group of species of the genera Phaseolus and Vigna (Papilionaceae) on the basis of morphological and pollen data, analysed by computer]. Boissiera 28: 166.
• Nakanishi, H., 1988. Dispersal ecology of the maritime plants in the Ryukyu Islands. Ecological Research 3(2): 163-174.
• Padulosi, S. & Ng, N.Q., 1993. A useful and unexploited herb, Vigna marina (Leguminosae - Papilionoideae) and the taxonomic revision of its genetic diversity. Bulletin du Jardin Botanique National de Belgique 62: 119-126.
• Pope, W.T., 1968. Manual of wayside plants of Hawaii, including illustrations, descriptions, habits, uses and methods of control of such plants as have a wild nature of growth, excluding ferns. C.E. Tuttle, Rutland, Vermont, United States. pp. 105-107.

Authors

• N.O. Aguilar