Archetypes of inflorescence: Genome-wide association networks of panicle morphometric, growth, and disease variables in a multiparent oat population

Authors: Carlson, Craig; Fiedler, Jason; NARAGHI, SEPHER MOHAJERI - North Dakota State University; NAZARENO, ERIC - University Of Minnesota; ARDAYFIO, NAAKORKOI - US Department Of Agriculture (USDA); MCMULLEN, MICHAEL - North Dakota State University; Kianian, Shahryar

Submitted to: Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/18/2022
Publication Date: 9/15/2022
Citation: Carlson, C.H., Fiedler, J.D., Naraghi, S., Nazareno, E., Ardayfio, N., Mcmullen, M., Kianian, S. 2022. Archetypes of inflorescence: Genome-wide association networks of panicle morphometric, growth, and disease variables in a multiparent oat population. Genetics. https://doi.org/10.1093/genetics/iyac128.
DOI: https://doi.org/10.1093/genetics/iyac128

Interpretive Summary: Grown as a source of food, feed, and cosmetics, cultivated oat is a major cereal crop with diverse end-products. Globally, oat production has suffered in the last decade due to competition for other high-value cereal crops and is increasingly challenged by both a rapidly changing environment and pathogen population. To ensure its relevance in the future, fundamental genetic improvements must be made. Historically, plant breeders have focused on evaluating oat populations for yield, agronomic traits, and disease resistance. What has been loosely assessed are the relationships of these important traits with panicle architecture (flower structure), and whether it can be modified to increase yield. Using 2,993 images from 10 diverse populations, this study reveals novel and reproducible models of panicle architecture and development, and their relationships with plant growth and disease resistance. Prior to this study, the genetics of panicle traits had not been well-characterized in oat. Genetic mapping in this population identified new regions associated with these and other important traits, of which comprise functionally relevant genes. These results facilitate new approaches to breeding and selection in oat and offer a unique perspective on the genetic basis of panicle architecture in cereal crops.

Technical Abstract: There is limited information regarding the morphometric relationships of panicle inflorescence traits in oat (Avena sativa) and their contribution to phenology and growth, physiology, and pathology traits important for yield. To model panicle architecture and identify genomic regions associated with corresponding traits, 10 diverse oat populations (n=2,993) were evaluated in the field and nine genotyped via genotyping-by-sequencing. Representative panicles from all progeny individuals, parents, and check lines were scanned, and images analyzed using manual and automated techniques, resulting in over 60 unique morphometric variables. Row-column spatial modelling and days to heading were used to account for environmental and phenological variance, respectively. Panicle variables were intercorrelated, providing reproducible models of panicle growth and architecture. Within and among family variance for panicle traits reflect their moderate to high heritability and shared mutual genome-wide associations (hotspots) with numerous high-effect loci. Candidate genes and potential breeding applications are discussed. This work adds to the growing genetic resources for oat and provides a unique perspective on the genetic basis of panicle architecture in cereal crops.