In vitro culture of Bambara groundnut [<i>Vigna subrerranea</i> (L.) Verdc., Favaceae ]: Effect of plant growth regulators, explant type and genotype on callus induction and differentiation

Abstract

A technique was developed to induce callus formation and differentiation using leaf, petiole and root explants from Bambara groundnut [Vigna subterranea (L.) Verdc.]. The combinations and concentrations of different
growth regulators were shown to be critical factors in the frequency of callus formation, as well as, in the potential for callus differentiation. It was established that the best responses in callus induction (75 %) were
obtained from petiole on a MS (Murashige and Skoog, 1962) basal medium, supplemented with 3 -5 mg/l N-benzylaminopurine (BAP) + 0.5 mg/l á-naphthaleneacetic acid (NAA). Callus growth (GI) was more
significant with Ci1 (3.52) and Ci4 (2.76) landraces, while root formation was especially observed with the Ci3 (24.81 %) landrace. Here, for the first time, induction of embryogenic and organogenic callus from petiole,
leaf and root of Vigna subterranea (L.) was reported. Both adventitious buds and somatic embryos were initiated after 3 months of subculture on a callus induction medium containing 3-5mg/l BAP + 0.1 -0.5 mg/l ANA. Somatic embryogenesis (50 - 68 %) occur more frequently than organogenesis
(11 - 27 %).

Un protocole a ete developpe pour induire la formation de cals, a partir des explants de feuille, de petiole et de racine chez le pois de bambara [Vigna subterranea (L.)]. Les combinaisons et les concentrations de
differents regulateurs de croissance se sont averees etre des facteurs determinants dans la frequence d'induction des cals, de meme que pour le potentiel de differenciation des cals. Les resultats montrent
egalement que l'induction des cals a ete plus importante avec le petiole (75 %) sur le milieu de base MS (Murashige et Skoog, 1962) supplemente avec 3 - 5 mg/l de la N-benzylaminopurine (BAP) + 0,5 mg/l de
l'acide ƒ¿-naphthalene acetique (ANA). La croissance des cals (IC) a ete plus importante avec les ecotypes Ci1 (3,52) et Ci4 (2,76), tandis que la rhizogenese a ete particulierement observee chez l'ecotype Ci3
(24,81 %). Pour la premiere fois, l'induction de cals organogenes et embryogenes a ete rapportee chez cette plante. Les bourgeons adventifs et les embryons somatiques ont ete inities apres 3 mois de subculture, sur
le milieu MS supplemente avec la BAP (3 - 5 mg/l) + ANA (0,1 - 0,5 mg/l). La frequence d'induction de l'embryogenese somatique (55 - 68 %) a ete plus elevee que celle de l'organogenese (11 - 27%).