Breeding potential of inbred lines derived from five maize (Zea mays L.) populations

Population improvement in maize (Zea mays L.) aims to increase favorable allele frequencies yet maintain genetic variability. The direction of future population improvement has usually been determined by evaluating the performance of maize populations after several cycles of selection. However, relatively few studies have been conducted to understand in advance the breeding potential of inbred lines derived from maize populations. The objective of the study was to evaluate combining abilities and heterosis for grain yield (GY) and related traits in 30 representative lines derived from five maize populations developed in China that are related to heterotic groups A, B, and D. Fifteen of 30 inbred lines that were derived from these five populations exhibited high yield potential. From among these 15 inbred lines, six lines were derived from Cpop.13, and three lines were derived from Csyn7, and four lines were derived from Cpop.14, while only one line was derived from each of Cpop.17 and Csyn5. Among the crosses between testers and lines derived from populations, seven crosses showed high heterosis for GY. These results indicated the inbred lines derived from the populations Cpop.13, Cpop.14, and Csyn7 could be suitable germplasm resources for further maize breeding. Five crosses XN8147 × Cpop.13, XN8147 × Cpop.14, XN8147 × Csyn5, CA446 × Csyn5, and CA446 × Csyn7 showed superior specific combining ability, yield, and standard heterosis over that of the check variety. Recurrent selection could be used to improve traits such as days to silking for Cpop.13, ear height for Cpop.14, and the ear height and stalk lodging for Cpop.17 and Csyn5 to increase favorable allele frequencies in derivatives of the five maize populations.