Effect of moisture content on in vitro regeneration of embryonic axis explants of cowpea (Vigna unguiculata L.)

To see the effect of ultra desiccation on seed survival, cowpea (Vigna unguiculata L.) seeds were conditioned to various moisture contents ranging from 8–2%. When monitored after one year of storage, variability was observed in seed viability in the seeds conditioned to different moistures. Seeds conditioned to very low moisture contents exhibited greater loss in viability. Therefore, efforts were made to see the possibility of germinating the embryo under artificial condition using various media and growth regulators. The effect of various combinations of hormone in plant tissue culture media were evaluated on the growth of excised embryonic axisin vitro to develop an embryo rescue protocol. An efficient protocol was developed for in vitro shoots regeneration from cowpea embryonic axis to improve the survival of low viability seeds to avoid the loss of potentially valuable genes. Shoots were developed in most of the explants on medium containing MS salts and B5 vitamins supplemented with 0.2 mg/l BAP. All the regenerated shoots were rooted on the same medium and in vitro plantlets were acclimatized in pots containing soilrite at room temperature. All the plants produced healthy seeds after 2 months in greenhouse. This protocol can be used to rescue cowpea germplasm with low germination percentage which results in successful regeneration.