Maize commercial hybrids compared to improved population hybrids for grain yield and agronomic performance

Improved maize (Zea mays L.) populations and population hybrids can both be profitable alternatives to commercial single-cross hybrids as well as good elite sources of diverse inbred lines. The objective of this research was to compare grain yield and agronomic performance between early maturing maize population hybrids and current early maturing commercial single-cross hybrids. This is a consequence of our research program targeted at identifying alternative heterotic patterns for the northern Corn Belt. Improved maize populations and population hybrids (S₀ generations) were evaluated in experiments arranged in randomized complete block and partially balanced lattice designs across 29 environments. Grain yield potential of population hybrids was optimally expressed under irrigated conditions. Data across environments showed that 20% of the population hybrids evaluated were not different (P 0.05) from at least one of the commercial single-cross hybrids for grain yield performance, root lodging, and stalk lodging percentages. The average mid-parent heterosis value across population hybrids from different geographic regions was 20.4% with negative estimates observed in only two population hybrids. Breeding efforts toward elite populations and population hybrids have demonstrated that germplasm improvement is extremely valuable and deserves public funding. These efforts should be supported in order to enable the development of elite sources of diverse inbred lines and the development of improved population hybrids for specific markets (e.g., organic) to increase producer options. Public maize breeding programs utilizing recurrent selection methods for germplasm improvement could address the need. These programs, however, should incorporate extensive testing of population hybrids.