Physiological Characterization of Trait Introgressed Lines of Rice (Oryza sativa L.) for Drought Stress Tolerance

Twenty-five lines of rice which were introgressed for root traits and water use efficiency (WUE) were physiologically characterized for drought adaptive traits in the present study. These lines along with the parents were screened for yield and other trait performance under semi-irrigated aerobic cultivation. Leaf temperature was selected as surrogate for root traits and SCMR for WUE. Apart from these traits, yield and yield associated traits, relative water content (RWC), membrane stability index and chlorophyll content were measured. The lower leaf temperature of trait introgressed lines than IR-64 suggests lines have better root biomass which enabled them to maintain its temperature. The yield performance of trait introgressed lines were better than recurrent parent, IR-64 under semi-irrigated aerobic cultivation. It indicates that the introgression of the respective traits onto an elite background, IR-64 improved the efficacy of the introgressed lines under water limited condition. Comparative analysis of introgressed lines for drought adaptive traits suggested G 25, G 4, G 12 and G 18 performed better than other lines. Therefore, these lines introgreseed for drought tolerance traits could be utilized for other breeding programs for further improvement in drought tolerance in rice for the development of elite genotypes.