New maize inbred development method I: Inter-heterotic group composite and tester choice
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2024-05-11
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Wiley Periodicals LLC on behalf of Crop Science Society of America
Abstract
Current maize (Zea mays L.) breeding methods and the limited germplasm infusion and mixing may slow the rate of genetic gain in the future. Using inter-heterotic group composites for maize inbred development has been questioned because of the issue of choosing appropriate testers. However, three observations can be revisited to facilitate the exploration of alternative methods. First, since the adoption of single-cross hybrids and the establishment of heterotic groups, the amount of heterosis has only been increasing slightly. Second, genomic analysis indicated the frequencies of the favorable alleles had significantly increased after a century's breeding. Third, the divergence of maize heterotic groups was preceded by the merging of landraces and diverse inbreds, after which three major heterotic groups were established. The objective of this study was to design different scenarios to generate inter-heterotic group composites and evaluate their usefulness in the commercial breeding program. We investigated two methods: the inter-heterotic group composite method (termed as super population [SupPop]) and the modified SupPop method (ModiSP, that is, backcrossing SupPop lines with elite inbreds). The results showed that the best scenario for the SupPop method was to use the SupPop inbreds to cross with a tester from the B14 group. When all four heterotic groups were mixed, the favored tester was from stiff stalk. However, ModiSP showed a higher chance of producing the best yield performance. These empirical results suggest that solutions can be proposed to identify the testers so that using inter-heterotic group composites for inbred development can be considered.
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This article is published as Zhang, Hongwei, Dongdong Li, Kendall R. Lamkey, Warren H. Stine, Jianming Yu, and Harry H. Stine. "New maize inbred development method I: Inter‐heterotic group composite and tester choice." Crop Science (2024). doi:https://doi.org/10.1002/csc2.21260. © 2024 The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
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Open access funding provided by the Iowa State University Library