Morpho-physiological traits associated with reproductive stage drought tolerance of rice (Oryza sativa L.) genotypes under rain-fed condition of eastern Indo-Gangetic Plain

Abstract

A field experiment was conducted under reproductive stage drought stress condition with the objective to determine the effect of water deficit stress on yield and yield attributes of 75 rice genotypes. The effect of drought stress on various physiological and biochemical traits associated with drought tolerance was also studies at reproductive stage in twelve promising genotypes selected on the basis of yield performance under stress condition. Result revealed that significant yield decline was observed almost in all rice genotypes grown under water deficit stress condition as compared to irrigated situation. Drought stress at reproductive stage caused reduction in relative water content (RWC) (31.57 %), membrane stability index (MSI) (25.8 %). 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 genotype. Out of the twelve rice genotypes, IR 84895-B-B-127-CRA-5-1-1, IR 83387-B-B-40-1, IR 83376-B-B-24-2, IR55419-04 and IR 83373-B-B-24-3 showed superiority in terms of grain yield, 1000 grain weight, total plant biomass, RWC, leaf area index (LAI), MSI and proline content. Significant and positive correlations were observed between yield and physiological attributes like proline content, LAI, relative water 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 reproductive stage.