Association mapping of flowering and height traits in Germplasm Enhancement of Maize doubled haploid (GEM-DH) lines

Authors: VANOUS, ADAM - Iowa State University; Gardner, Candice; BLANCO, MICHAEL - Retired ARS Employee; MARTIN-SCHWARZE, ADAM - Iowa State University; LIPKA, ALEXANDER - University Of Illinois; Flint-Garcia, Sherry; BOHN, MARTIN - University Of Illinois; Edwards, Jode; LÜBBERSTEDT, THOMAS - Iowa State University

Submitted to: The Plant Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/4/2018
Publication Date: 3/15/2018
Citation: Vanous, A., Gardner, C.A., Blanco, M., Martin-Schwarze, A., Lipka, A.E., Flint Garcia, S.A., Bohn, M., Edwards, J.W., Lübberstedt, T. 2018. Association mapping of flowering and height traits in Germplasm Enhancement of Maize doubled haploid (GEM-DH) lines. The Plant Genome. 11(2):170083. https://doi.org/10.3835/plantgenome2017.09.0083.
DOI: https://doi.org/10.3835/plantgenome2017.09.0083

Interpretive Summary: Problem Statement - Flowering and plant and ear height-related traits are extensively studied in maize for three main reasons: 1) ease of obtaining phenotypic measurements, 2) advancements in genotyping and sequencing technologies have reduced the cost of genomic information, and 3) the importance of these traits for adaptation and grain yield. Variation in flowering time and plant and ear height traits is extensive and findings from previous studies are genotype specific. Herein, a diverse panel of exotic derived doubled haploid maize lines, in conjunction with genome-wide association analysis was used to further explore adaptation related trait variation of exotic germplasm for potential use in adapting exotic germplasm to the U.S. Corn-Belt. Accomplishment - Analyses of DNA based markers and phenotypic data resulted in identification of eighteen and nineteen candidate genes for height and flowering related traits, respectively. A single gene was found that affected both flowering and height related traits. Contribution - Finding of candidate genes will allow for future investigation into these genes and findings will be incorporated into the Germplasm Enhancement of Maize Project to aid in the the adaptation of exotic germplasm to the central-U.S. Corn-Belt. Ability to more readily adapt unadapted germplasm will allow plant breeders to use unique germplasm in breeding programs for improvement of abiotic and biotic stress and other performance traits.

Technical Abstract: Flowering and plant and ear height-related traits are extensively studied in maize for three main reasons: 1) ease of obtaining phenotypic measurements, 2) advances in genotyping and sequencing technologies have reduced the cost of genomic information, and 3) the importance of these traits for adaptation and grain yield. Variation in flowering and height traits is extensive and findings from previous studies are genotype specific. Herein, a diverse panel of exotic derived doubled haploid lines, in conjunction with genome-wide association analysis is used to further explore adaptation-related trait variation of exotic germplasm for potential use in adapting exotic germplasm to the U.S. Corn-Belt. Phenotypes for the association panel were obtained from six locations across the central-U.S. and genotyping was performed using the genotyping-by-sequencing method. Nineteen flowering time candidate genes were found for three flowering traits. Eighteen candidate genes were found for four height related traits, with the majority of the candidate genes relating to plant hormones auxin and gibberellin. A single gene was discovered for ear height that also had effects on FT-like flowering gene expression levels. Findings of this study will be used in future research that can be implemented in the USDA Germplasm Enhancement of Maize breeding project and contribute to rapid adaptation of exotic germplasm to temperate U.S. environments.