Regeneration Efficiency in Trifolium apertum as Influenced by Explant Media Interaction

Abstract

In vitro response of interaction of various growth regulators and explants was studied in Trifolium apertum (genotype EC 401712), a diploid species domesticated in Russia. The species is considered as a progenitor of T. alexandrinum, a very important fodder legume cultivated in Indian sub-continent. The callus induction was found to be dependent on level of growth regulators, auxin and cytokinin ratio and the explants. Medium ‘A’ with low level of growth regulators failed to induce callus in 5 out of 6 explants. High hormone medium ‘D’ showed good callogenesis in hypocotyl, cotyledon and petiole explants. In collar, leaf and root explants the frequency of callus induction was very low. Friable green calli were observed in hypocotyl and petiole explants. The high auxin: cytokinin ratio favoured callus induction. NAA in high concentration was found to be better than Picloram as auxin source. The differences in callus induction frequency were found to be statistically significant for both explant and media as well as their interaction. The calli from petiole explant-‘D’ medium combination showed very good organogenetic and embryogenetic potential on sub-culture. 50% of sub-cultures showed shoot induction and a large number of them showed root induction in rooting media. A suitable protocol for regeneration and transfer of plantlets in vitro in this genotype of T. apertum has been developed for first time. The cytology of the plants revealed normal meiotic pairing with 8 bivalents.