The evidence for non-additive effect as the main genetic component of plant height and ear height in maize using introgression line populations

Abstract

With 2 figures and 5 tables Abstract Two populations, one comprising 98 near-isogenic introgression lines (Z3HBILs) with a Zong3 genetic background, and the other comprising a backcross population developed by crossing introgression lines per se with Zong3, were employed to identify quantitative trait loci (QTL) for plant height and ear height (EH) in maize grown at 2 years representing different environments. Nine QTL for plant height (PH) were detected, on chromosomes 1, 2, 3, 5 and 6, using inclusive composite interval (ICI) mapping. The extent of their contribution to phenotypic variation ranged from 3.1% to 22.6%. Fifteen QTL for EH were detected, on chromosomes 1, 2, 3, 4, 5, 6 and 8, and their contribution to phenotypic variation ranged from 5.6% to 31.2%. These QTL mainly showed non-additive effects. In addition, 158 interacting pairs were detected among the QTL for the two traits. Interactions among the identified QTL accounted for only a small proportion of QTL pairs (19.6%), the percentage of phenotypic variation explained by an individual QTL pair ranged from 4.2% to 32.0% for PH and from 3.6% to 31.0% for EH respectively. Contrarily, non-additive pairs accounted for a higher proportion. In addition, 30 additive × additive pairs accounted for only 19.0% of the interaction pairs. Overall, the non-additive effect was the predominant genetic component of PH and EH in maize.