This study aimed to investigate the combining ability and heterotic effects on grain yield (GY), oil content (OC) and crude protein (CP) in tropical and temperate maize lines. Hybrids and inbred lines were evaluated in a complete diallel scheme without reciprocals, in two experiments in randomized blocks with three replications. The partitioning of the sum of squares for general (GCA) and specific (SCA) combining ability indicated that both additive and non-additive effects were involved in the genetic control of the studied traits. The estimates of the quadratic components showed predominance of non-additive genetic effects in the trait control. However, for OC and CP, the non-additive effect had a clearly negative influence on the hybrid combinations. The cross L6x L10was considered promising, because it associated RG positively with BP and OC.
Zea mays L.; combining ability, heterosis; Griffing method, plant breeding
