Variation for Drought Tolerance in Hill Rice Genotypes

Twenty five hill rice genotypes were evaluated for their relative drought tolerance under water stress (E₁) and irrigated (E₂) environments. All the characters studied were significantly affected by water stress. The grain yield m⁻² ranged from 208g to 694g under stress conditions (with mean of 465.2gm⁻²), where as under irrigated (E₂) conditions it ranged between 295g to 1024g. The grain yield reduction in E₁ from E₂ ranged from 7.54% to 59.28% with an overall reduction of 33.51%. Panicles m⁻² reduced under water stress at tillering stage to the extent of 30.95% from irrigated environment. Panicle components like panicle length, spikelets panicle⁻¹ and spikelets fertility resulted irrlesser number of grains panicle⁻¹. Fourteen genotypes exhibited high spikelet fertility (>80%) for which test weight ranged from 23.15 to 29.73g suggesting that these traits mostly decide the yield level under water stress conditions. The stress susceptibility index (SSI) among genotypes ranged from 0.27 to 2.12 indicating great sensitivity of material studied to water stress. Correlation studies revealed that under water stress, yield had significant association with harvest index, grains panicle⁻¹, 1000-grain weight and spikelets panicle⁻¹, it was concluded that water stress resulted in poor grain yield due to reduction in panicle m⁻², grains panicle⁻¹, spikelet fertility and harvest index. Minimum reduction in grain yield of SKAU-338, K-78, SKAU-337 and Baderwah-1 under water stress and displaying lower SSI (<0.5) indicated their tolerance and hence yield stability.