Developing a high-yielding and provitamin A-rich maize variety is one of the best approaches to reduce malnutrition and increase production, especially in regions where maize is a staple food, such as, the former Katanga Province in the Democratic Republic of the Congo. However, it requires a good knowledge of combining ability and heterosis for grain yield and provitamin A. Thus, evaluating grain yield, provitamin A content and other agronomic traits of eight lines, four testers, and their 32 hybrids occurred during the 2015-2016 and 2016-2017 cropping seasons. The results showed that genetic parameters related to combining ability and heterosis among various F₁ hybrids influenced all the studied traits except plant height. The parental genotypes P6 and P10 were suitable for improving 100-kernel weight, grain yield, stature at ear insertion, and provitamin A content. The parental genotypes P7, P4, and P2 were promising for provitamin A content, while the parental genotype P3 was leading for grain yield. Five hybrids (P10 × P5, P10 × P6, P10 × P7, P10 × P8, and P11 × P5) showed distinction as the best specific combinations for improving productivity and provitamin A content. The F₁ hybrid P10 × P6 with desirable specific combining ability revealed that it is helpful as the best combination in producing double and triple hybrids with the highest yield and provitamin A potential. Crosses P10 × P5 and P11 × P5 can serve as the best cross combinations for grain yield, while hybrids P10 × P7 and P10 × P8 showed promising for provitamin A content. The presented results could benefit future breeding programs to develop maize genotypes with high yield and provitamin A elements, alleviating food insecurity and malnutrition.

Keywords: Maize (Zea mays L.), heterosis, line-by-tester combining ability, GCA and SCA, grain yield, provitamin A

Key findings: The presented study indicates that both additive and non-additive effects contribute to the genetic control of grain yield and provitamin A content in maize (Zea mays L.). Some parental lines, testers and their hybrids have better mean performance for the assessed traits. The parental line P6 and tester P10 appeared as the best general combiners suitable for hybridization to improve the grain yield and provitamin A content. The F₁ hybrid P10 × P6, followed by P10 × P5, P10 × P7, P10 × P8 and P11 × P5, was the best cross combination for desirable heterotic and combining ability effects for higher grain yield and provitamin A content.