Identification of Heterotic Loci for Seven Yield and Yield-Related Traits in Maize with a Set of Introgression Lines.

Dissection of the genetic basis of heterosis facilitates hybrid breeding in crops. In this study, heterotic loci (HL) for seven yield and yield-related traits were identified in a set of maize introgression lines (ILs) under two environments (locations)by a backcross population with one of their parents, Zong 3. Middle parent heterosis of seven yield and yield-related traits was calculated based on the field experiments conducted at two locations. A total of 120 significant loci for six traits were identified by calculating marker-trait coefficients with the software Graphical Genotypes (GGT) 2.0, and 48 loci represent for five traits were commonly identified under two environments. This indicates that it is possible to identify HL with the population derived from ILs. Of the 48 significant loci, 13were found to be associated with more than 2 different traits, indicating strong genetic correlations among these traits. For yield and most of the yield-related traits, the heterozygosity of the markers at the HL were strongly correlated to the performance of middle parent heterosis, suggesting that the HL identified in this study could be used for heterosis prediction and maker-assisted selection in maize hybrid breeding.