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 nutrient medium supplemented with various concentrations of benzyladenine (BA) and napthaleneacetic acid (NAA) alone or in combination. Soybean plantlets could be regenerated only when 0.05–0.1 μM BA was applied in conjunction with 1 μM 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 μM) in association with low levels of NAA (0.05 μM) 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 μM BA). Elongated bean shoots differentiated roots on half-strength MS medium containing 1 μM indoleacetic acid (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 μM BA was applied in combination with 10 μM NAA. Multiple axillary branching occurred from the main shoots regenerated from chickpea meristems; however, rooting occurred only when these shoots were recultured on medium containing 1 μM indolebutyric acid (IBA). Plantlets regenerated from the meristems of all these grain legumes were successfully transferred to pots and grown to maturity.