Combining ability studies on yield and yield components in rice

摘要

Combining ability was studied for grain yield, days to 50 percent flowering, plant height, productive tillers plant.t, panicle length, number of fertile grains panicle, spikelet fertility percent and 100-grain weight using line X tester analysis involving three CMS lines and 33 restorer lines. The combining ability analysis revealed that, in general, the variances due to sca were higher than gca variances for all the characters, indicating the predominance of non additive gene interaction in governing yields and related traits. This suggests the possibility of exploiting heterosis in this self pollinated crop. Among CMS lines studied, V 20 A is good general combiner for earlyness, whereas IR 58025A and IR 62829A were rated as good general combinerfor yield. Ten restorers viz., R_2, R_4, R_5, R_7, R_9, R_(15), R_(17), R_(22), R_(30) and R_(31) were rated as good general combiners for yield. These also showed average to good gca effects for yield components. Seventeen cross combinations exhibitedhigh sca effects for yield. These crosses were found to involve at least one parent with high gca and other parents having either high, average or low gca effect indicating the involvment of additive as well as nonadditive genetic interactions operatingin these crosses.