Evaluation of mutant rice genotypes for tolerance to high temperature

Abstract

Rice (Oryza sativa L.) is planted in about a tenth of the arable area around the world and is the largest source of food energy for half of humanity. Climatic change with increasing frequency of severe and prolonged drought periods and significant increases in air temperature has affected global rice production. Therefore, generating mutant rice cultivars tolerant to high temperatures and low water supplies is of utmost importance. Advanced mutant rice lines which were derived from irradiated Amistad -82 and J-104 were evaluated in the field under high temperatures and low water supply conditions using Amistad-82 variety as control. The genotypes with the best and worst field performances were compared using physiological parameters such as cell membrane thermostability, pollen viability, lipid peroxidation, and peroxidase and catalase activity under high temperature conditions. Three mutant lines, 8852, 8552 and LP-12 showed high yielding under high temperatures and low water supplies conditions in the field and also showed better pollen viability, cell membrane thermo stability, lipid peroxidation and peroxidase than LP-16 mutant lines and the control cv. Amistad-82. These results show that the physical irradiation of seeds with protons followed by subsequent in vitro embryo culture using 2,4D may generate genetic variability for tolerance to high temperatures. The variation observed for the physiological and biochemical indicators evaluated could be used for the early selection of high temperature tolerant rice genotypes