Effect of water stress at reproductive stage on yield potential and stability of rice (Oryza sativa L.) genotypes grown in rainfed lowland conditions

Abstract

The present study was conducted at ICAR research complex for eastern region, Patna during kharif 2012 and 2013 with objective to identify rice genotypes having high yield potential and stability under water stress (drought) conditions. Fifteen rice (Oryza sativa L.) genotypes were grown under irrigated and water stress conditions. Water stress was imposed at reproductive stage by withholding irrigation supply. Yield and yield attributes of rice genotypes under water stress condition were recorded. The effects of water stress on various physio-morphological traits associated with drought tolerance were also studied at reproductive stage. Results revealed that, significant yield decline was observed in most of the genotypes grown under stress condition compared to non-stress condition. Drought susceptibility index (DSI) and relative grain yield (RY) were used to illustrate yield stability and yield potential, respectively. Significant variation in drought susceptibility index and relative yield values within genotypes were observed. The DSI values ranged from 0.68 to 1.46 and the mean RY values were 0.85 for irrigated plots and 0.77 for water stressed plots. The rice genotypes IR 83376-BB-24-2, IR 83373-B-B-24-3 IR 84895-B-B-127-CRA-5-1-1 and IR83387-B-B-27-4 showed high yield potential and stability (i.e. DSI<1; and RY>mean RY). These drought tolerant genotypes were also superior in terms of grain yield and higher content of desired physio-morphological traits in terms of plant biomass, relative water content, soluble protein and proline content. These drought tolerant rice genotypes may be adopted in large area in rainfed lowland ecosystem where drought is frequent, particularly at reproductive stage.