In Vitro Callus Proliferation from Stem Explants of Three Varieties of Green Gram after In Situ Ultraviolet-B Exposure

The in vitro callus induction was carried out with stem explants (nodal region from third node from top of canopy) harvested on 30 days after seed germination from in situ control and supplementary ultraviolet-B irradiated (UV-B = 2 hours daily @ 12.2 kJ m -2 d -1 ; ambient = 10 kJ m -2 d -1 ) three varieties of green gram viz. CO-8, NVL-585 and VAMBAN-2 to evaluate the viability of the stem explants for the purpose of germplasm storage. Callus and axillary bud initiation occurred only in NVL-585 control stem explants. Stem explants of CO-8 and VAMBAN-2 controls failed to proliferate callus. Stem explants of all UV-B exposed green gram varieties also failed to proliferate callus losing the possibility of utilizing them for germplasm conservation.