Heterosis for antioxidant enzymes in rice hybrid under abiotic stress conditions

Activities of superoxide dismutase (SOD), glutathione reductase (GR), catalase (CAT) were analyzed in rice hybrid DRRH-2 and its respective male (DR 714-1-2R) and female (IR 68897A) parents under water, salinity and low temperature stresses. The superoxide dismutase (SOD) activity was significantly increased in all the three stresses and in all the three genotypes, while highest increase was observed under water stress condition. In case of glutathione reductase (GR) activity the hybrid did not show significant change with the type of stress, where as male parent exhibited decrease and female parent exhibited increase in the enzyme activity under water stress and salt stresses. The catalase activity decreased in all the three types of stresses in hybrid and both parents, while the reduction was relatively higher in male parent followed by hybrid. The hybrid DRRH-2 showed distinct heterosis under all the stresses for the activities of SOD and GR as indicated by their heterosis over the better of parents (HOBP) and heterosis over the mean of parents (HOMP) values, while for CAT activity these heterosis values were non-significant. From the study, we conclude that heterotic vigor for the antioxidant enzymes (SOD, GR) played a role in improvement of stress tolerance in hybrid than the parental lines, which could be an important biochemical basis towards understanding the heterosis under abiotic stress conditions.