In Vitro Callus Induction in Leaf Explants of Black Gram Varieties Grown Under In Situ UV-B Radiation

Callus induction was tried with leaf explants (third leaf from top of canopy) harvested from 30 DAS (days after seed germination) in situ control and supplementary UV-B irradiated (UV-B = 2 hours daily @ 12.2 kJ m -2 d -1 ; ambient = 10 kJ m -2 d -1 ) VAMBAN-3, NIRMAL-7 and T-9 varieties of black gram to study their viability for utilization in germplasm conservation. Callus induction occurred only in leaf explants of in situ grown VAMBAN-3 and NIRMAL-7 controls. Parenchyma cells in the callus of control VAMBAN-3 were larger and less in number compared to NIRMAL-7. VAMBAN-3 and NIRMAL-7 varieties had 57.14% similarity between them, while T-9 remained separated showing only 14.28% similarity with other members. The leaf explants excised from all varieties of black gram cultivated under in situ UV-B stress, failed to induct callus as they succumbed to the abiotic stress.