Combining ability analysis and nature of gene action for grain yield in Maize hybrids
Abstract
In the present investigation combining ability analysis and nature of gene action was studied for twenty lines, four testers and eighty hybrids, which were obtained from Line x tester biparental crossing scheme. The twelve characters were studied for winter maize under this experiment. Parental variance, Line variance, and line x tester variance revealed that there were significant differences in all the characters, whereas only tester variance showed three non-significant characters, namely days to 50% anthesis, days to maturity and cob length. The nature and magnitude of gene action showed that the dominance variance major reason towards hybrid performance for all characters. This means that non-additive action is important for the hybrid performance. The most promising crosses for higher yield per ha were L8 x T1 (27.63), L9 x T4 (23.44), L3 X T3 (23.41), L16 x T2 (23.03), L3 x T3 (22.81), L1 x T3 (22.51), L20 x T2 (19.48), L13 x T4 (19.47), L7 x T1 (18.22) and L17 x T4 (17.58) which have shown high SCA effects for grain yield which high parental GCA effects can be exploited for the development of SCHs because of non-additive gene action.
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Introduction
Maize (Zea mays L.) is an important cereal crop belonging to tribe Maydeae, of the grass family, Poaceae. Maize always been a versatile crop and used for various purposes, for example, feed, fodder, silage and ethanol production. In plant breeding maize hybrid had contributed a lot in terms of production. The higher yield of maize hybrid than inbred and composites is the main reason of its preference for commercial production. The production of promising hybrids for commercial cultivation is only accomplished by a perfect parental combination, which can judge by their combining abilities. Combining ability can be defined as the ability of a genotype to inherit its required economic performance to its crosses. Therefore, combining ability analysis is an effective tool for identifying superior parents for hybrids and was first reported by Sprague and Tatum (1942). Combining ability is dissected into two parts general combining ability (GCA) and specific combining ability (SCA). Both GCA and SCA variances have been determined and related to the possible types of gene action involved. The variance of GCA includes an additive genetic portion, while, SCA variance usually includes the nonadditive genetic variance of the total genetic variance arising largely from dominance and epistatic deviation. In the current investigation, combining ability analysis and nature of gene action was tested using line x tester mating design in order to sort out promising maize inbred lines and hybrid which can be utilized for the commercial production.
Conclusion
In the current investigation SCA effects represent mainly dominance effect (additive × dominance, dominance × dominance effects). The crosses showing SCA effects involving parents with good GCA could be exploited. However, if a cross having high SCA has parents of which one is good combiner and another as poor or average combiners, such crosses are likely to throw some good segregants only if the additive genetic system is presently in a good general combiner and epistatic effects on the cross, act in the same direction so as to maximize the desirable expression of the characters in question (Lonnquist, 1961). Thus crosses namely, L8 x T1 (27.63), L9 x T4 (23.44), L3 X T3 (23.41), L16 x T2 (23.03) which have shown high SCA effects for grain yield, which high parental GCA effects can be exploited for the development of SCHs because of nonadditive gene action for yield and yield component traits.
