Combining Ability for Kernel Starch Content in Maize Synthetic Populations Obtained from Local Populations

Synthetic populations of maize (Zea mays L) are low-cost and stable varieties, obtained by cross pollination of a group of inbred lines, local population or hybrids. The main advantage of these populations is that the heterosis does not diminish significantly in F2. In order to complete the research on the combining ability of maize synthetic populations, the objective of this work was to study seven maize synthetic populations, determining their general combining ability (GCA) and specific combining ability (SCA) for kernel starch content, as well as their potential as source populations in breeding programmes.To achieve the proposed objectives, we studied top cross hybrids of the type “inbred line x synthetic population” resulted from the crossing between seven synthetic maize populations and four early inbred lines used as tester. For all experimental conditions, the differences between genotypes were statistically assured for kernel starch content. The experimental years and testing locations have provided conditions for differentiation of genotypes for starch content and interactions between the environment and genotypes were statistically significant, indicating dependence of starch content on environmental conditions. The additive effects for starch content provided by GCA were high for Tu SRR 5DR(6I)(5) and Tu SRR 5D (2I)(2). Non additive effects, corresponding to SCA were high for the following hybrid combinations: TC 233 x TuSyn 1 (3), CO 255 x Tu SRR 5D (2I)(2) and TC 209 x Tu SRR 5DR(6I)(5). In the case of synthetic maize populations, the determinism of starch is influenced equally by GCA and SCA.