Evaluation of drought tolerant indices for screening of some elite rice genotypes under normal and drought stress condition

The present study comprised of selected 20 rice genotypes was evaluated to identify the drought stress tolerant genotypes under non-stress (NS) and stress (S) conditions during the year 2022-23. This experiment employed a randomized block design with three replications. The fourteen drought tolerant indices Yield Stability Index (YSI), Yield Index (YI), Drought Resistance Index (DRI), Mean Productivity Index (MPI), Geometric Mean Productivity (GMP), Harmonic Mean (HM), Tolerance Index (TOL), Stress Tolerance Index (STI), Drought Susceptibility Index (DSI), Yield Reduction Ratio (YR), Goldean Mean (GOL), Stress Susceptibility Index (SSPI), Modified Stress Tolerance Index (K1STI and K2STI) were calculated based on grain yield under non-stress (NS) and stress (S) conditions. The yield reduction by drought conditions ranged from 42-60%. Based on drought tolerant indices and ranking method, the genotypes AU1GSR, ANNA R4 and PMK2 showed as the most drought tolerant. Correlation analysis revealed that yield in stress condition (Ys) was significantly and positively correlated with YSI, YI, DRI, MPI, GMP, HM, TOL, STI, SSPI, K1STI, and K2STI. Further, principal component analysis showed that 72.26% of SSPI, STI, MPI, HM, GMP, YSI, GOL, DRI, YI, K1STI and K2STI. PCA indicated that first two principal components accounted for the more than 92.78% of the total variances for drought tolerant indices. Furthermore, drought tolerant indices MPI, GMP, HM, TOL, STI, DSI, GOL and SSPI can be used as the most suitable predictors for screening drought tolerance genotypes and AU1GSR, PMK3, PMK2, ANNA R4, IR14G3556 and IR14G3615 considering the highest tolerance to drought yield potentials of the genotypes. Hence, they are recommended to be used as donor parents in a drought breeding programme.