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Description
Fairly strong twiner, usually with fusiform tuberous root;
stems usually clothed with spreading silky hairs. Leaflets three, acute
at the apex, obliquely and broadly cuneate to almost rounded at the base,
the terminal one 7.5 to 15 cm long, all dark green and with appressed strong
silky hairs on both surfaces. Flowers pink or purplish, turning yellow,
2.5 cm long, on two- to four-flowered peduncles 7.5 to 30 cm long, keel
prolonged into an uncurved beak. Pod recurved, linear, 7.5 to 9 cm long,
silky (Andrews, 1952).
Distribution
It is common in the central Sudan, Zaire, Senegal, Sierra Leone,
Liberia, Côte d'Ivoire, Togo, Nigeria, Republic of Cameroon, Angola,
Ethiopia, Kenya, Tanzania, Malawi, Zambia, Colombia and Venezuela.
Characteristics
V. vexillata is an annual with good seedling vigour and good
wet-season growth, and is effective in weed suppression. The seed shatters
and it is not a good standover feed for the dry season. It is frost- and
fire-susceptible (Downes, 1966). Although hairy, it is quite palatable
(Bermudez, Ceballos and Chaverra, 1968) . It spreads fairly well naturally
and will appear seasonally in crop stubble. It did not perform as well
as cowpea (Vigna unguiculata) at the Kimberley Research Station, in northern
Australia (Parbery, 1967b). Its best yield of dry matter was only 309 kg./ha
unfertilized and 525 kg./ha with 100 kg. N/ha on the heavy Cunnunurra clay
and 1 122 kg./ha on unfertilized Cockatoo sand. Added nitrogen at 100 kg./ha
depressed the yield on Cockatoo sand. In Zambia, van Rensburg (1967) obtained
2 780 kg. DM/ ha.
The plant seeded in 91 days on Cockatoo sand and in 126 days on Cunnunurra
clay. Milford (1967) found that the dry-matter intake of the actively growing
flowering plant was one of the highest recorded among tropical legumes,
but intake fell after the plants were severely frosted. The crude protein
content of the dry matter at flowering was 20.3 percent, of which 80.9
percent was digestible.
It produced excellent leafy growth in Zambia and covered the ground
quickly. It yielded 1 442 kg. DM/ha but made no regrowth after cutting
(van Rensburg, 1967).
Links for the genus:
- Vigna
germplasm: Current status and future needs (report prepared by the Vigna
Crop Germplasm Committee)
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