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

Abstract

The present experiment comprised of 48 rice genotypes was conducted to identify stress-tolerant genotypes underreproductive stage drought stress and controlled conditions during Rabi 2017-18. Drought tolerance indices likestress 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 reductionwas observed under drought stress in the majority of the rice genotypes studied. Drought stress at reproductivestage 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 highDTE and STI and low SSI and TOL were identified as drought-tolerant genotypes. Based on screening, rice genotypesPM 17015 and PM 15048 showed low SSI and TOL and high DTE and STI values were identified as drought-tolerantgenotypes. The present study indicates that selection based on stress tolerance indices likes DTE, SSI, STI and TOLwill result in the identification of drought-tolerant genotypes for the rainfed ecosystem.