Use of meta-Topolin (mT) has significantly affected tissue culture results in several plant species. In this study, a fast and efficient micropropagation protocol for Withania somnifera was standardized. Also, a comparison was made between the effect of using M.S. media supplemented with mT and M.S. media supplemented with different concentrations of B.A.P. + AdSO(4) on the in vitro regeneration of W. somnifera. M.S. media supplemented with I.B.A. was used to obtain a healthy and advantageous root system. The resulting plantlets were analyzed for their total chlorophyll and protein content. The comparison revealed that 2.5 mg/l mT supplemented M.S. media showed better results with 88.9 +/- 0.42% bud breaking percentage, a shoot multiplication rate of 22.4 +/- 4.16 shootlets per explants, total chlorophyll content of 0.887 +/- 0.004 mg/g and protein content of 25.67 +/- 0.25%. Healthy adventitious root systems were observed in regenerated shootlets inoculated in M.S. media supplemented with 2.0 mg/l I.B.A. During hardening, 80% of plants treated initially with mT survived. Whereas treatment with M.S. media supplemented with 1.0 mg/l B.A.P. + 50 mg/l AdSO(4) resulted in bud breaking percentage of 61.1 +/- 0.09%, a shoot multiplication rate of 15.8 +/- 7.81 shootlets per explant, total chlorophyll content of 0.7194 +/- 0.0055 mg/g and protein content of 23.33 +/- 0.25%. During hardening, 78% of plantlets treated initially with B.A.P. + AdSO(4) survived. Therefore, the study concludes that mT may be used as an alternative source of cytokinin for obtaining healthy plantlets with a higher rate of plant regeneration in W. somnifera. Key message The study carried out to standardize a viable protocol for meta-Topolin as alternative source of cytokinins in micropropagation for Withania somnifera and to compare the effects using different phytohormones.
