Environment-specific selection alters flowering-time plasticity and results in pervasive pleiotropic responses in maize

Authors: CHOQUETTE, NICOLE - North Carolina State University; Holland, Jim - Jim; WELDEKIDAN, TECLEMARIAM - University Of Delaware; DROUAULT, JUSTINE - Inrae; DE LEON, NATALIA - University Of Wisconsin; Flint-Garcia, Sherry; Lauter, Nicholas; MURRAY, SETH - Texas A&M University; XU, WENWEI - Texas Tech University; WISSER, RANDALL - Inrae

Submitted to: New Phytologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/6/2022
Publication Date: 3/16/2023
Citation: Choquette, N.E., Holland, J.B., Weldekidan, T., Drouault, J., De Leon, N., Flint Garcia, S.A., Lauter, N.C., Murray, S., Xu, W., Wisser, R. 2023. Environment-specific selection alters flowering-time plasticity and results in pervasive pleiotropic responses in maize. New Phytologist. 238(2):737-749. https://doi.org/10.1111/nph.18769.
DOI: https://doi.org/10.1111/nph.18769

Interpretive Summary: Climate change has precipitated the need to adapt crops to novel environments. To understand how new sources of diversity can be incorporated across geographical zones, we used experimental evolution based on selection for early flowering within a common base population in parallel at eight sites across a latitudinal gradient spanning 3100 km and 28 degrees latitude. We then tested how all selection lineages varied across the sites of selection for the target trait and 32 other traits. Flowering time was changed by selection via generalized and local modes of adaptation. This transformation led to widespread changes in other developmental, architectural, and yield traits, expressed collectively in an environment-dependent manner. Photoperiod was the environmental variable most strongly associated with the magnitude of selection response, and similarity of photoperiod between selection and evaluation environments was primarily responsible for the pattern of local adaptation. Our findings validate calls for selecting crops for local environments and provide guidance for adapting maize to climate change.

Technical Abstract: Climate change has precipitated the need to more quickly adapt crops to novel environments. To understand how new sources of diversity can be incorporated across geographical zones, we performed a parallel evolution experiment in maize. Initialised with a common population of tropical origin, multi-generational selection on flowering time was performed at eight field sites spanning 25 degrees latitude, a 3,100 km transect. We then jointly tested all selection lineages across the original sites of selection, for the target trait and 32 other traits.Modeling intergenerational shifts in a physiological reaction norm revealed separate components for flowering-time plasticity underlying generalized and local modes of adaptation. In turn, selection altered the plasticity of each lineage, leading to a latitudinal pattern in the responses to selection that were strongly driven by photoperiod. This transformation led to widespread changes in developmental, architectural, and yield traits, expressed collectively in an environment-dependent manner. Furthermore, selection for flowering time alone alleviated a maladaptive syndrome and improved yields for tropical maize in the temperate zone.Our findings show that maize can undergo rapid changes in its flowering phenology and plasticity. They also demonstrate that selecting crops to local conditions can accelerate adaptation to climate change.