General and Specific Combing Ability of Maize (Zea mays L.) Inbred Line for Grain Yield and Yield Related Traits Using 8×8 Diallel Crosses

Abstract

Combining ability is the genotype's ability to pass the desired character to the offspring. Hence, combining ability information is needed to determine the crossed pairs in the formation of hybrid varieties. Therefore, this study was conducted to estimate general and specific combining ability effects of maize inbred lines for yield and yield-related traits. Eight maize inbred lines were mated through a half diallel mating design (Griffing’s Method IV, Model I). The resulting twenty-eight F1 hybrids for twenty one characters were evaluated using Alpha-Lattice Design with three replications during 2018 main cropping season at Haramaya University Research Site (Raare). Genetic analysis of variance due to mean squares revealed significant differences for general combining ability (gca) and specific combining ability (sca) effects indicated the presence of additive as well as non additive gene effects in governing the inheritance of these traits. These results confirm the possible involvement of both additive and non-additive gene actions in the inheritance of these characters and can be improved either by recurrent selection or even by heterosis breeding methods like production of hybrids, synthetics and composites. However, relative magnitude of these variances indicated that additive gene effects were more prominent for most of the characters studied since the ratio of GCA:SCA were more than unity in most of the traits. Parental line L3 and L8 were good general combiner for grain yield and L1, L2, L6 and L7 are desirable for earliness. The better performing four crosses L3×L6, L3×L8, L2×L5, and L6× L8 were good specific combiners for grain yield, which could be utilized for developing high yielding hybrid varieties as well as for exploiting hybrid vigor.