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.
Highlights
Maize (Zea mays L.) is monoecious plant and highly crosspollinated species, which is belongs to the tribe Maydeae of the grass family Poaceae, Genus Zea, Species mays [1]
Mean square due to specific combining ability and general combining ability was significant for grain yield, biomass yield, days to anthesis, days to silking, plant and ear height, husk cover, plant aspect, ear aspect, common rust (Puccinia sorghi), days to maturity, thousand kernel weight, kernels per row, harvest index, and Turccicum leaf blight (TLB), which indicated that this trait were governed by both additive and non-additive type of gen action
Additive type of gene action had preponderance to control grain yield, number of ear per plant, plant aspect, ear aspect, rust, harvest index, turcicum leaf blight, ear rot, thousand kernel weight, days to maturity, plant height, biomass yield, husk cover since general combining ability (GCA)/specific combining ability (SCA) ratio was greater than unity
Summary
Maize (Zea mays L.) is monoecious plant and highly crosspollinated species, which is belongs to the tribe Maydeae of the grass family Poaceae, Genus Zea, Species mays [1]. Maize breeding programs designed for specific-end uses; the development of commercial maize hybrids for grain yield, improve quality trait and tolerant to biotic or abiotic stress usually require good knowledge of combining ability of the breeding materials to be used since it provides information for breeder to select better parent as it discloses the mode of inheritance for various plant traits and to determine the nature and magnitude of gene action involved in the inheritance of the traits. According to Sprague and Tatum [9] who contribute to our understanding combining ability analysis is one of the most powerful tools in identifying the best combiners that may be used in crosses either to exploit heterosis or to accumulate productive genes that enable the breeder to design effective breeding plan for future improvement of the existing materials. This study was conducted to estimate general and specific combining ability effects of maize inbred lines for yield and yieldrelated traits
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