Department of Crop Physiology, C.S. Azad University of Agriculture and Technology, Kanpur-208002.
A pot experiment was conducted in a wire-net house to determine the effect of ten day spells of drought, given either at tillering or at flowring, in comparison to normally irrigated controls, on relative water content (RWC), nitrate reductase activity (NRA), yield and yield components of plants and their recovery after irrigation at the end often days duration of moisture stress treatment, in ten genotypes of rice. Relative water content and NRA were decreased when plants were subjected to drought at tillering and flowering stages. Under these stress conditions, genotypes Annada, IET 11677, IET 11675 and IET 11672 had higher RWC and NRA in their leaves and, thus, maintained higher recovery percentage of RWC and NRA. Drought at flowering stage was more detrimental than at tillering stage. It seems that plants were more sensitive to water stress during the flowering stage. Genotypes IET 11677 and Annada, which had higher number of grains and grain weight/panicle, grain yield/plant, harvest index and grain productivity per plant under stress showed greater tolerante to water stress in both the situations of drought.
