Somatic embryogenesis and in vitro plant regeneration in moth bean [Vigna aconitifolia (Jacq.) Marechal]: a recalcitrant grain legume

An efficient in vitro regeneration protocol for moth bean [Vigna aconitifolia (Jacq.) Marechal] via somatic embryogenesis has been developed. Embryogenic callus cultures were established from the cotyledonary node as explant on semi-solid Murashige and Skoog (MS) medium supplemented with 0.75 mg l(-1) 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.5 mg l(-1) 6-benzylaminopurine (BA) and with various additives (50 mg l(-1) ascorbic acid and 25 mg l(-1) each of adenine sulphate, citric acid and l-arginine). Numerous somatic embryos differentiated on MS basal nutrient medium supplemented with 0.25 mg l(-1) 2,4-D and 0.5 mg l(-1) of kinetin (Kin). Sustained cell division resulted in the formation of cell aggregates, which progressed to the globular- and heart-shaped somatic embryos and then, if they differentiated properly, to the torpedo shape and cotyledonary stages. The transfer of embryos onto fresh MS basal medium containing 0.2 mg l(-1) BA and 2.0 mg l(-1) gibberellic acid enabled the embryos to achieve complete maturation and germination. More than 80% of somatic embryos were converted into true-to-type fertile plants. In vitro-regenerated plantlets with well-developed roots were successfully hardened in a greenhouse and established in soil.