Plant regeneration from meristems of grain legumes: soybean, cowpea, peanut, chickpea, and bean

Abstract

The regeneration potential of shoot apical meristems of soybean, cowpea, peanut, chickpea and bean was studied on agar solidified MS [Murashige and Skoog] nutrient medium supplemented with various concentrations of benzyladenine (BA) and naphthaleneacetic acid (NAA) alone or in combination. Soybean plantelets could be regenerated only when 0.05-0.1 .mu.M BA was applied in conjunction with 1 .mu.M NAA. Cowpea meristems did not require exogenously supplied hormones for maximum (100%) plant regeneration to occur. Extremely low levels of BA (0.1-0.005 .mu.M) in assocation with low levels of NAA (0.05 .mu.M) also induced plant regeneration at very high frequency. Similarly, bean meristems differentiated into plantlets on hormone-free medium or on medium containing only the auxin, NAA. Multiple bud regeneration (15-30 buds per meristem) was induced from bean meristems at high cytokinin levels (10 .mu.M BA). Elongated bean shoots differentiated roots on half-strength MS medium containing 1 .mu.M IAA. Although most combinations of BA or BA and NAA induced shoot regeneration from peanut and chickpea meristems, whole plant regeneration occurred more frequently (75%) from the former only when 0.1 .mu.M BA was applied in combination with 10 .mu.M NAA. Multiple axillary branching occurred from the main shoots regenerated from chickpea meristems; rooting occurred only when these shoots were recultured on medium containing 1 .mu.M IBA. Plantlets regenerated from the meristems of all these grain legumes were successfully transferred to pots and grown to maturity.