Two Vigna Species Native to Argentina with Ornamental Potencial

HOC, P. S. & OJEDA, F. S.

ACTA HORTICULTURAE

ISHS

Año: 2013 vol. 1000 p. 83 - 90

0567-7572

Vigna candida (Vell.) Maréchal, Mascherpa and Stainier and V. adenantha(G.F.W. Meyer) Maréchal, Mascherpa and Stainier have potential as ornamentalsand could be used as forage crops in warm areas. They are scandent, stolonate andpluriannual. In both species the flowering period begins in springtime and last untilautumn. The flowers are flag blossoms, disposed in 5-10-flowered racemes of 10 cmlong. The standard and the keel are white, the wings are white with violet nectarguides; a variation in the color pattern of these petals occur between the species.During the anthesis, that lasts 1-2 days, an anular nectary that surround the ovarysecrete the nectar offered as reward. Legitimate flower visitors are species ofXylocopa, Centris and Bombus (Hymenoptera), because of only these individuals cantrigger the system of pollen transfer; also, nectar and pollen thieves or robbers weredetected but did not affect the reproductive success. In V. candida, aroma is alsoemitted as other secondary attractant. Experiments of controlled pollinations werecarried out in order to know the reproductive system of each species. V. adenantha isself-compatible but the reproductive success reach the 100% when pollinators visitthe flowers, oppositely, in V. candida, which is self-incompatible, if pollinators do notwork, fruits and seeds cannot be produced. Because of the growing pattern,phenology, the beautiful and conspicuous flowers, and the nitrifying capacity, bothspecies should be appreciated as ornamentals in warm or temperate areas, even inflooded land.