COMBING ABILITY ESTIMATES AND MODE OF INHERITANCE FOR DROUGHT RELATED TRAITS IN GENETICALLY DISTANT MAIZE ACCESSIONS (Zea mays) - M. Aslam; I. A. Khan; S. M. A. Basra (Journal of Animal and Plant Sciences, 2012)
Ten genetically distant maize accessions with variable response to different levels of moisture were crossed following line × tester mating fashion. All the germplasm was evaluated at normal and stress moisture levels against some physiological and morphological parameters i.e. leaf temperature, leaf area, stomatal frequency, stomatal size, silk elongation rate, 100-grain weight and grain yield per plant for two years. General and specific combining abilities and heterotic effects were determined along with percent contribution of lines, testers and line × testers in the inheritance of traits. Using dominance and additive variance values, potence ratio was calculated for all the traits at both moisture levels. General combining ability (GCA) effects of lines and testers had variable magnitude and directions. On the basis of GCA effects accessions A50-2, M-14, WFTMS, and N48-1 could potentially be used in the hybridization programme. Crosses A50-2 × B-34, A50-2 × WFTMS, NC-9 × B-34, NC-9 × N48-1 and B-42 × WFTMS have high specific combining ability (SCA) effects for most of the parameters studied. There was variable magnitude and direction of heterotic effects at both the moisture levels shown by most of the traits. Partial dominance was found for all the traits under study except 100 grain weight and grain yield per plant.
Keywords: journal article; Maize; moisture stress; line × tester; GCA and SCA