EFFECTS OF DROUGHT STRESS ON HYBRIDS OF VIGNA RADIATA AT GERMINATION STAGE

Drought is one the critical abiotic factors that reduces the germination, growth and yield of crops. Therefore the present project was designed with the objective to screen the best drought tolerant hybrid of Vigna radiata. Genetic variations for drought tolerance among these hybrids were assessed by simple and efficient technique. Seven hybrids of V. radiata (9801, 7002, 9706, 08003, 07007, 97012 and 08007) were used for screening against three levels of drought stress (zero, control), 5% (-0.05 MPa) and 10% (-0.1 MPa) induced by Polyethyleneglycol (PEG(6000)). A higher proline content was observed in 07007 (6.10 mu g/g fresh weight) as compared to all other hybrids. Treated seedlings of each hybrid were compared with their respective control to evaluate the differences in their growth under drought. Different parameters such as percentage of germination, germination stress tolerance index (GSI), shoot and root weights (bath fresh and dry) and lengths, root length stress index (RLSI), dry matter stress index (DMSI) and plant height stress index (PHSI) showed considerable variations. Germination percentage, shoot weights, PHSI and DMSI decreased in all hybrids along with the increase of PEG induced drought stress (5% and 10% PEG). In contrary, root weights and RLSI were increased under drought. Overall 07007 showed a better performance, and can therefore be classified as a drought tolerant hybrid.