Optimizing factors affecting adventitious shoot regeneration, in vitro flowering and fruiting of Withania somnifera (L.) Dunal

The effects of plant growth regulators, sucrose and temperature on adventitious shoot regeneration, in vitro flowering and fruiting of Withania somnifera were investigated. The highest frequency of shoot regeneration (96%) with an average of 22.8 shoots per stem segment was obtained on Murashige and Skoog (MS) medium fortified with 2.0 mg l−1 kinetin, 0.5 mg l−1 α-naphthaleneacetic acid (NAA), 0.3 mg l−1 gibberellic acid (GA3) and 40 g l−1 sucrose. The greatest frequency of rooting (100%) with an average of 14.1 roots per shoot was obtained when the regenerated shoots were cultured on the half-strength MS medium containing 2.0 mg l−1 indole-3-butyric acid (IBA) and 15 g l−1 sucrose. Regenerated plantlets were successfully established in the soil with 98% survival rate. The acclimatized plants grew well, developed flowers that were morphologically similar to the donor plants. The highest frequency of flowering (88%) with an average of 8.3 flowers per shoot and the greatest frequency of fruiting (74.9%) with an average of 5.1 fruit per shoot were obtained when shoot tips were cultured on MS medium fortified with 0.3 mg l−1 N6-benzyladenine (BA) and 60 g l−1 sucrose, and maintained at 20 °C. Seeds were separated from the in vitro formed mature fruits and placed on MS medium containing 0.3 mg l−1 GA3 to test their viability. The percentage of seed germination was 66%. The developed in vitro culture protocol can be useful for large scale propagation, genetic transformation and plant breeding studies.