Estimation of combining ability and gene action in field corn (Zea mays) using line × tester analysis

Abstract

The study investigates the combining ability and gene action for yield and related traits in maize using a line × tester mating design. Eight inbred lines and five testers were evaluated to understand the genetic control of key agronomic traits. The analysis revealed that specific combining ability (SCA) played a more significant role than general combining ability (GCA), indicating the predominance of non-additive gene actions, particularly over-dominance. The findings suggest that heterosis breeding is a promising strategy for improving maize yield and related traits. Significant variability in SCA effects across hybrids highlighted the importance of specific parental combinations. Notably, hybrids IGI-22-58 × VL1055 and IGI-22-17 × ZL135440 demonstrated superior performance, making them strong candidates for commercial use and further breeding efforts. The study underscores the importance of selecting parental lines with desirable GCA effects while focusing on hybrid combinations with strong SCA effects to maximize breeding outcomes. This research provides valuable insights for maize breeding programs, emphasizing the need to prioritize non-additive genetic effects to achieve substantial genetic gains.