Studies on heterosis and its relation to genetic divergence in maize (Zea mays L.) inbred lines

Heterosis and its relation to genetic divergence between the parents was explored in a diallel cross among 8 inbred lines of maize (Zea mays L.) selected from an array of 32 inbreds, derived from 4 genetically and geographically diverse populations, on the basis of genetic distance deduced through Mahalanobis' D-2 statistic on 20 diagnostic and agronomic traits. Pooled analysis was carried out for calculating heterosis as the error mean squares at the two locations were homogenous. Heterobelteosis was observed in all the traits under study for many crosses. Among the top ten heterotic hybrids, the highest frequency of crosses were with intermediate genetic distance followed by high genetic divergence between the parents. However, a few crosses with low genetic divergence also fell in the category of top 10 hybrids. It was realized that parents with high per se performance and intermediate genetic divergence produced highly heterotic as well as high yielding hybrid.