Drought Stress Screening in Backcross Inbred Lines of Rice (Oryza sativa L.) at Germination and Seedling Stage

Drought is a key stress factor that limits rice production globally. The present study was carried out to identify drought tolerant rice lines at the germination and seedling stages using polyethylene glycol (PEG) induced stress. Twenty promising high yielding BC2F4 lines, stacked with drought yield QTLs qDTY₁⸳₁ and qDTY₁₂.₁, derived from the cross between Manu Ratna X Improved White Ponni, were subjected to drought stress. Drought was imposed during germination using three levels (0, 10 and 15%) of polyethylene glycol (PEG 6000) concentrations. The experiment was conducted in factorial completely randomized block design with three replications and the observations on number of seeds germinated, root length, shoot length, germination index, germination stress tolerance index, fresh weight stress tolerance index, dry weight stress tolerance index and seedling vigour index were evaluated after stress treatment. A significant difference was noted among lines for characters under drought stress. Among the lines, MIB-29-2-3-1, MIB-29-8-5-35, MIB-43-5-3-66 and MIB-119-5-7-33 were selected which showed higher germination percentage, root length, shoot length, germination stress tolerance index and and seeding vigour index. The selected lines can be further evaluated in the field to develop drought tolerant rice varieties.