Identification of drought tolerant, high yielding rice genotypes for rainfed upland ecosystem of Uttarakhand hills through different drought tolerance indices

Aim: To identify drought tolerant rice genotypes for rainfed upland hills at reproductive stage through different drought tolerance indices, PCA Biplot Analysis and Cluster Analysis. Methodology: Forty eight rainfed upland genotypes were evaluated under drought stress at reproductive stage and non-stress (irrigated) conditions. Different drought tolerance indices viz., drought tolerance efficiency (DTE), mean productivity index (MPI), relative efficiency (REI), mean relative performance (MRP), stress tolerance index (STI), drought yield index(DYI), stress tolerance (TOL), stress susceptibility index (SSI) and Schneider's stress susceptibility index (SSSI)were used for screening genotypes. Results: The reduction in grain yield was observed in all the genotypes grown under drought stress condition and the per cent reduction in grain yield between stress and non-stress trial varied from 23.62% to 67.69%. The highest value of DTE was recorded in VL 20541 (76.38%) whereas VL 20441 showed the highest value for MPI (2656), REI (1.478), MRP (2.44) and STI (0.79). The lowest value of DYI (1.31), TOL (625), SSI (0.51) and SSSI (-0.23) was observed in VL 20541. Highest value for DTE, MPI, REI, MRP, STI and lowest value for DYI, TOL, SSI, SSSI are preferred and desirable as it indicate drought tolerance. A positive and highly significant correlation was exhibited by grain yield under stress (YS) with DTE, MPI, REI, MRP, STI and highly negative significant with DYI, TOL, SSI SSSI indicating that selection of low DYI, TOL, SSI, SSSI value and high DTE, MPI, REI, MRP, STI for screening of rice genotypes under drought stresses condition. Principal component analysis revealed that PC1 and PC2 accounted for 80.05% and 19.40% of the total variations, respectively. Cluster analysis grouped the 48 rice genotypes into two main clusters. Interpretation: On the basis of drought tolerant indices, PCA Biplot analysis and Cluster analysis six genotypes viz., VL 20441, VL 20225, VL 20541, VL 20468, VL8549, and VL20316 were identified as drought tolerant.