Study of physiological and biochemical responses of rice mutant lines derived from gamma ray irradiation and local varieties under saline field conditions

Rice (Oryza sativa L.) is one of the crops which is the main source of food for more than a third of the world's population. Limiting factors such as environmental stress require increasing the yield of agricultural products per unit area. Soil salinity is one of the most important factors reducing the productivity of crops throughout the world. Induced mutation is widely used as an effective tool for improving the yield, quality, and resistance to biotic and abiotic stresses in product modification. In order to screen salt-tolerant superior mutant lines of rice, 10 mutant lines (M5) derived from three Iranian local varieties (Tarom, Anbarbo, and Hasani) were assessed during two generations (M6 and M7) at saline field (EC of soil was 6-8 ds/m). The experiment was conducted based on a randomized complete block design with three replications. Three salt-tolerant superior mutant lines (13-3, 32-18 and 22-1) were selected in comparison with their parents (control). Physiological parameters of superior mutant lines (high stomatal conductivity, Fv/Fm, and total chlorophyll) were biochemical (lower Na+/K+ ratio, high proline accumulation, less membrane damage). These superior mutant lines will be introduced as new salt-tolerant rice varieties and sources of plant germplasm.