Determination of stress indices for selection of superior genotypes under drought situation in rice (oryza sativa L.)

Abstract

One of priority research area in rice is identification of suitable genotypes for rain fed condition. Quantifying the drought tolerance genotypes was done with different stress indices obtained from the yield data under severe drought and irrigated condition with four backcross inbred lines derived from the cross between IR64 (drought susceptible) and Apo (drought tolerant) which carried three mega QTL in different combination of classes namely qDTY2.2, qDTY3.1 and qDTY8.1. The genotype CB 229 is the highly tolerant one confirmed by tolerant and susceptible indices, which had three DTY QTL (qDTY2.2, qDTY3.1 and qDTY8.1) combinations maximizes the yield in drought condition. Among the selection indices, YI, MPI, DRI, STI, HM, GMP, MRP and RE are the best indices to identify tolerant genotype. Clustering based on principal component analysis exhibits that CB 229, CB 193-2 and CB 193-3 falls on the quarter where tolerant indices found. Overall study shows that the selection based on stress indices may be rewarded to identify superior genotypes under severe drought condition.