Abstract
Okra is an important vegetable crop and very few studies have been carried out for the development and in vitro regeneration of somatic embryos. In this study, we have developed an efficient protocol for somatic embryogenesis from cotyledonary leaf explants of Okra (Abelmoschus esculentus L. Monech). In this investigation, the genotype CoBhH1 of A. esculentus was tested with different amino acids and casein hydrolysate for the optimization culture conditions and development of somatic embryos. The explants were cultured on Murashige and Skoog (MS) medium containing Gamborgs (B5) vitamins, 400mg/l l-glutamine, 300mg/l casein hydrolysate, 8g agar, 1.5mg/l 2, 4-dichlorophenoxyacetic acid (2, 4-D) and 1mg/l naphthaleneacetic acid (NAA). Proembryoids were observed after 4weeks of regular subculturing in the same media. Globular to torpedo shaped somatic embryo development was observed after 8weeks of culture. Mature embryos were selected by their cotyledonary stage and subcultured on the regeneration medium. Half strength MS medium containing B5 vitamin (half strength), 30g sucrose, 8g agar, 1mg/l BAP and 0.5mg/l GA3 were used for regeneration and shoot elongation. A total of 17.43 plantlets were obtained from single explant through this protocol. The plantlets were transferred to plastic cups in laboratory condition and finally transferred to the greenhouse with a 100% survival rate. Inter simple sequence repeats (ISSR) analysis was used to check the genetic fidelity of regenerated plants. No polymorphism was detected revealing the genetic integrity of regenerated plantlets. The regenerated plants were morphologically similar to those of the mother plant.
•We have developed a highly effective protocol for somatic embryogenesis and regeneration using cotyledonary leaf explants of A. esculentus.•The addition L-glutamine and casein hydrolysate in MS medium showed increase in the frequency of somatic embryo maturation and plant regeneration.•ISSR analysis confirmed the genetic integrity of the micropropagated plants. This protocol can be used for transformation and other molecular studies in A. esculentus.•This is the first report for successful somatic embryogenesis from the cotyledonary leaf explants of A. esculentus and confirmation of genetic fidelity of regenerated plants using ISSR markers.