Heritability and genetic gain for grain yield and path coefficient analysis of some agronomic traits in early-maturing maize hybrids

Abstract

Breeders face serious challenges in breeding early-maturing maize hybrids which are required by farmers in marginal environments. The objectives of the study were to determine the genetic gain for breeding for high yield, and investigate levels of genetic variation, heritability and associations between grain yield and secondary traits in early-maturing hybrids. Fifty maize hybrids were evaluated at three sites in KwaZulu-Natal, South Africa in a 5 × 10 α-lattice design with two replications. Genetic gain for grain yield of 18 % was reflected by the top five experimental hybrids over the population mean, indicating a significant improvement. One of the top five hybrids 14XH293 was early-maturing and non-significantly different from other three top yielding intermediate to late hybrids but was as early as the early commercial checks. Significant genetic variation for grain yield, plant and ear height, grain moisture, days to anthesis and silking, ear position, ear prolificacy, number of ears and anthesis-silking interval was observed, indicating opportunities for further improvement of the hybrids. Grain yield was highly heritable (75 %) but heritability ranged from low (3 %) to high (79 %) for secondary traits. Both correlation (P ≤ 0.001) and regression (P ≤ 0.001) indicated that ear prolificacy is the highest contributor to grain yield improvement. Furthermore, ear prolificacy displayed the major direct effects on yield that was greater than its correlation with yield, indicating that selection for this trait would indirectly improve grain yield of early-maturing maize hybrids.