Phenotypic plasticity contributes to maize adaptation and heterosis

Authors: LIU, NANNAN - Fujian Agricultural & Forestry University; DU, YUANHAO - Huazhong Agricultural University; Warburton, Marilyn; XIAO, YINGJIE - Huazhong Agricultural University; YAN, JIANBING - Huazhong Agricultural University

Submitted to: Molecular Biology and Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/10/2020
Publication Date: 11/3/2020
Citation: Liu, N., Du, Y., Warburton, M.L., Xiao, Y., Yan, J. 2020. Phenotypic plasticity contributes to maize adaptation and heterosis. Molecular Biology and Evolution. 38(4):1262-1275. https://doi.org/10.1093/molbev/msaa283.
DOI: https://doi.org/10.1093/molbev/msaa283

Interpretive Summary: Maize is one of the most productive crops due to the high level of hybrid vigor or heterosis. Although breeders have known for decades how to exploit this heterosis, researchers have been unable to explain all of it at the genetic level. In this study, for a population of 976 maize hybrids were we collected data for 12 morphological and agronomic traits in 6 to 11 environments. Phenotypic plasticity was analyzed as the different performance of each hybrid in response to the influence of varying environments. Our analyses of this data, combined with DNA sequence information from all hybrids, will aid in understanding the genetic mechanisms causing phenotypic plasticity and this information will be used to increase heterosis in new maize cultivars.

Technical Abstract: Plant phenotypic plasticity describes altered phenotypic performance of an individual when grown in different environments. Exploring genetic architecture underlying plant plasticity variation may help mitigate the detrimental effects of a rapidly changing climate on agriculture, but little research has been done in this area to date. In the present study, we established a population of 976 maize F1 hybrids by crossing 488 diverse inbred lines with two elite testers. Genome-wide association study identified hundreds of quantitative trait loci associated with phenotypic plasticity variation across diverse F1 hybrids, the majority of which contributed very little variance, in accordance with the polygenic nature of these traits. We identified several quantitative trait locus regions that may have been selected during the tropical-temperate adaptation process. We also observed heterosis in terms of phenotypic plasticity, in addition to the traditional genetic value differences measured between hybrid and inbred lines, and the pattern of which was affected by genetic background. Our results demonstrate a landscape of phenotypic plasticity in maize, which will aid in the understanding of its genetic architecture, its contribution to adaptation and heterosis, and how it may be exploited for future maize breeding in a rapidly changing environment.