Somatic Embryogenesis and Plant Regeneration from Hypocotyl Explant of Green Gram (Vigna Radiata L) – A Recalcitrant Grain Legume

A protocol for plant regeneration via somatic embryogenesis was developed in two high yielding green gram cultivar TAP-7 & Pusabaisaki. Somatic embryos were induced from hypocotyl explants on MS medium fortified with different concentrations of 2, 4-dichlorophenoxyacetic acid (2,4-D), 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), α-naphthalene acetic acid (NAA) and picloram either singly or in combination with 0.5–1.5 mg/l N⁶-benzylaminopurine (BAP) or 0.5–1.5 mg/l kinetin (KN). Type of auxin, its concentration and genotype influenced the frequency of somatic embryogenesis. NAA was better for somatic embryo induction compared to other auxins. The well formed, cotyledonary shaped embryos germinated into plantlets with 62.4% frequency on MS medium supplemented with 0.5 mg/l BAP + 0.75 mg/l ABA. The frequency of embryogenesis and subsequent plantlet regeneration was higher in TAP-7 than in Pusabaisaki. Regenerated plants were transferred to soil and grown to maturity with 30% survival. This protocol to produce embryos with a high frequency and their subsequent conversion to whole plants offers potential for gene transfer and development of transgenics in this important grain legume.