THIDIAZURON INDUCED PLANT REGENERATION IN BRASSICA RAPA VAR. TURNIP VIA SEED DERIVED CALLI INDUCTION AND RADICAL SCAVENGING ACTIVITY

The present study is first report on in vitro regeneration and antioxidant potentials of economically important Brassica rapa var. turnip from seed derived calli and using Thidiazuron (TDZ (1-phenyl-3- (1, 2, 3- Thiadiazol-5-yl) as primary growth regulator. Results exhibited that seed germination medium supplemented with TDZ (2mgL^-1) and NAA (1mgL^-1) yielded highest frequency of callus induction (71.3%) within 7 days of culture. Shoot differentiation was achieved within five weeks of callus transfer to MS medium with similar concentrations of growth regulators. Medium containing TDZ (1mgL^-1) and BA (1mgL^-1) provided optimum conditions for in-direct shoot organogenesis (28 shoots per callus). Furthermore, the addition of TDZ (0.5mgL^-1) to MS medium containing BA (1mgL^-1) produced as long as 2.8cm shoot. TDZ improved antioxidant potential of regenerated plantlets, roots and shoots as compared to control plants and their parts. Highest frequency of radical scavenging activity was observed in seed derived calli (80.1%). All in vitro regenerated plants were successfully rooted and acclimatized to in vivo conditions. This study contributes to better understanding of mechanism of TDZ as potential growth regulator for regeneration via seed derived callus and increased radical free scavenging activity in Brassica rapa var. turnip.