Studies on indices and morphological traits for drought tolerance in rainfed rice (Oryza sativa L.)


The present experiment comprised of 48 rice genotypes was conducted to identify stress-tolerant genotypes under reproductive stage drought stress and controlled conditions during Rabi 2017-18. Drought tolerance indices like stress susceptibility index (SSI), drought tolerance efficiency (DTE), stress tolerance index (STI) and stress tolerance (TOL) and morphological traits responses were employed in screening of the genotypes. Significant yield reduction was observed under drought stress in the majority of the rice genotypes studied. Drought stress at reproductive stage caused a reduction in grain yield (51%), a number of panicles per square metre (15%), panicle length (13%), spikelet fertility (17%), plant height (9%) and harvest index (26%). The variation in SSI values ranged from 0.83 – 1.33, DTE from 36.90-66.67%, STI ranged from 0.39-1.02 and TOL varied from 0.98 -2.97. The genotypes with high DTE and STI and low SSI and TOL were identified as drought-tolerant genotypes. Based on screening, rice genotypes PM 17015 and PM 15048 showed low SSI and TOL and high DTE and STI values were identified as drought-tolerant genotypes. The present study indicates that selection based on stress tolerance indices likes DTE, SSI, STI and TOL will result in the identification of drought-tolerant genotypes for the rainfed ecosystem.

Research Article