Combining ability and heterosis for yield and grain quality characters in rice (Oryza sativa L.)

Twelve F₁ crosses derived from four lines and three testers, crossed in L x T mating design were utilized to estimate the combining ability and heterosis for 17 yield and grain quality traits and also to detect the superior crosses for the breeding program. Analysis of variance showed significant differences among all the traits under study except for plant height in lines. In the case of testers, the traits viz., the number of tillers per plant, the number of productive tillers per plant, hundred seed weight, single plant yield, alkali spreading value, amylose content, gel consistency, kernel length, kernel length breadth ratio, kernel length after cooking and kernel breadth after cooking showed significant values. The SCA variance was higher than the GCA variance for all the characters under study except the alkali spreading value indicating the predominance of non-additive gene action in the inheritance of all the characters. The parents TKM 13, CO 52, ADT 52 and IRBB 21 were adjudged as good general combiners with respect to single plant yield. Hence, these parents can be exploited through pedigree breeding to obtain better recombinants by selection in later generations. Based on the results of perse performance, standard heterosis, and sca effects, the hybrids viz., CO 52 x IRBB 60 and ADT 52 * IRBB 21 were identified as the best specific combiners and these could be used for future breeding.