Effect of drought on yield potential and drought susceptibility index of promising aerobic rice (Oryza sativa L.) genotypes

Selection of drought tolerance is highly complex and involves evaluating genotypes either for high yield potential or stable performance under varying degrees of water stress. Seventeen advanced rice genotypes were evaluated under aerobic and water stress condition at Department of Genetic and Plant Breeding, GKVK, UAS, Bangalore during summer 2010. Water stress was imposed at late vegetative stage by withholding irrigation supply in one experiment for 15 days and other was maintained as aerobic control. Drought susceptibility index (DSI) and Relative yield (RY) values were used to describe yield stability and relative yield among genotypes. In the present study, there were high variations in drought susceptibility index and relative yield among genotypes. DSI values ranged from -9.37 (25P25) to 18.48 (IR 68897B) and mean RY values were 0.707 and 0.752 for Aerobic condition and water stress respectively. Higher relative yield under water stress indicated the positive response of genotypes to drought. The varieties MAS26, SEL 128, 25P25, PHB 71, MAS25, IR 58025B and MAS946-1 showed high yield potential and yield stability (i. e., DSI mean RY). MAS26 and SEL 128 not only have yield stability but they also have high per day productivity per drop of water. So these varieties could be further tested for drought confirming characters and could be used as donor parents in drought tolerance breeding in rice