Genetic analysis to assess the physiological efficiency of parental lines in rice (oryza sativa L.)

Information on physiological potential of the genotypes is more important in the crop improvement programme, to evolve hybrids suitable for aerobic cultivation. Four CMS lines and 22 male parents were subjected to combining ability analysis and evaluated to identify the best combining parents for developing rice hybrids suitable for aerobic condition. The investigation was carried out under aerobic condition using the line x tester mating design in three replications and studied for different biometrical and physiological traits. The aerobic rice culture IR 72875-94-3-3-2 had high per se performance for grain yield, yield traits followed by higher harvest index, SPAD values, relative water content, total dry matter and root dry weight. The other genotype IR 71604-4-1-4-7-10-2-1-3 had superior performance for grain yield and for most of the yield contributing traits, relative water content and root length. The hybrids involving IR 72875-94-3-3-2 namely IR 68886A x IR 72875-94-3-3-2, IR 68888A x IR 72875-94-3-3-2 and COMS 14A x IR 72875-94-3-3-2 had higher grain yield under aerobic condition. Similarly PSBRC 80, the male parent best suited for aerobic condition had better performance for most of the traits like harvest index, high relative water content, total dry matter production, root dry weight and grain yield. PSBRC 82, the other aerobic culture also had, higher harvest index, leaf chlorophyll content, relative water content and grain yield. The female parents IR 68888A and COMS 14A and the male parents IR55838-B2-2-3-2-3, IR 36, WGL 14 and WGL 32100 had good performance for most of the yield contributing traits and physiological parameters under aerobic condition. The hybrids developed from these parental lines viz., IR 68888A x IR55838-B2-2-3-2-3, IR 68888A x IR 36, IR 68888A x WGL 14, IR 68888A x WGL 32100, COMS 14A x IR55838-B2-2-3-2-3, COMS 14A x IR 36, COMS 14A x WGL 14 and COMS 14A x WGL 32100 were found superior for most of the yield traits and physiological traits. Therefore, these parental lines could be best utilized for developing high yielding hybrids suitable for water limited conditions.