Heterosis and combining ability studies in rice hybrids (Oryza sativa L.) with an emphasis to gall midge resistance
Sameena Begum, V Ram Reddy, B Srinivas, Ch Aruna Kumari
The aim of this study was to develop rice hybrids with resistance to gall midge and make inferences regarding components of heterosis in hybrids obtained by crossing six lines and seven testers in Line X Tester mating design. General combining ability (GCA) of parents (six lines and seven testers) and specific combining ability (SCA) and heterosis among 42 hybrids for gall midge resistance, yield and its related traits were analyzed. The magnitude of SCA variances was higher than GCA variance for all the traits except panicle length and thousand-grain weight, where the GCA variance was higher. Among the lines, JMS 21A was found to be a good general combiner for spikelet fertility, number of grains per panicle, grain yield per plant and gall midge incidence. Among the testers, JR 67 recorded high grain yield per plant along with favorable GCA for the number of grains per panicle, grain yield per plant and gall midge incidence. Most of the hybrids recorded positive significant standard heterosis for grain yield per plant. Hybrid JMS 19A X JR 80 recorded significantly positive SCA effect and highest relative heterosis, heterobeltiosis and standard heterosis over checks for grain yield per plant along with moderate resistance to gall midge. The alleles that control resistance to gall midge resistance have a degree of dominance more than 1, which indicates a favorable situation for obtaining resistant hybrids.
Sameena Begum, V Ram Reddy, B Srinivas, Ch Aruna Kumari. Heterosis and combining ability studies in rice hybrids (Oryza sativa L.) with an emphasis to gall midge resistance. International Journal of Ecology and Environmental Sciences. 2020; 2(4): 113-123.