In vitro studies of epicotyl and embryo culture in cultivated, wild and inter-specific hybrids of okra (Abelmoschus spp.)

The present study aimed to determine the optimal concentration of growth regulators for regenerating Abelmoschus species through epicotyl and embryo culture. Five popular okra genotypes (four varieties, one inbred), two wild species and interspecific hybrids from crossing var. Pusa Sawani with wild relatives were used to develop in vitro regeneration protocol. SSR primers confirmed the hybridity of interspecific crosses. A total of 64 different combinations of indole-3-butyric acid (IBA), naphthalene acetic acid (NAA) and kinetin, referred to as MSOM1 to MSOM64 were used to test regeneration efficiency. Among these combinations, MS medium supplemented with NAA and IBA each with concentration of 0.5-1 mg/L and kinetin @ 1- 1.5 mg/L proved to be effective for regeneration using epicotyl and embryo explants in cultivated okra genotypes, wild species and interspecific hybrids. Regeneration efficiency in cultivated genotypes through epicotyl culture ranged from 40 to 65%. However, for both cultivated genotypes and wild species regeneration efficiency ranged from 25 to 65% by embryo culture. On an average, interspecific hybrids achieved regeneration efficiency of 35% to 75% through embryo culture. The present study indicated that the success of apical shoot culture and embryo culture in okra is influenced by the genotype, type of growth hormones and their concentrations.