Response of physiological and biochemical parameters in deeper rooting rice genotypes under irrigated and water stress conditions

An experiment was conducted under vegetative stage drought stress condition with the objective to determine the effect of water deficit stress on various physiological and biochemical traits associated with drought tolerance attributes of twelve promising rice genotypes selected on the basis of deeper rooting abilities. Drought stress at vegetative stage caused reduction in relative water content (RWC) (31.57%), grain yield (55.31%), number of effective tillers (37.70%), plant biomass (23.65%), and increase in grain sterility (51.5%) and proline content (55.9%) in rice genotypes. However, the responses varied among genotypes. Out of the twelve rice genotypes, Bamawypan, showed superiority in terms of grain yield, 1000-grain weight, total plant biomass, RWC, leaf area index (LAI), proline content, catalase activity, peroxidase activity and total chlorophyll content. Significant and positive correlations were observed between yield and physiological attributes like proline content, LAI, relative water content, catalase activity, peroxidase activity, total chlorophyll content and plant biomass under drought stress condition. The current study indicated that the physiological and biochemical traits have direct or indirect effect on yield performance of rice genotypes under water stressed environment at vegetative stage.