Genome-wide association for β-glucan content, population structure, and linkage disequilibrium in elite oat germplasm adapted to subtropical environments

High beta-glucan content is one of the main goals of oat breeding programs worldwide. However, the genomic regions and genes controlling beta-glucan content in oats are not fully understood. In this sense, the objectives of this study were as follows: (i) to characterize structure and linkage disequilibrium (LD) in a panel of oat germplasm adapted to subtropical environments; and (ii) to identify genomic regions associated with oat beta-glucan content. An oat panel with 413 genotypes was evaluated for beta-glucan content under subtropical conditions in different years and genotyped using genotyping-by-sequencing. Population structure, LD, and genome-wide association (GWA) analyses were carried out. GWA mapping was performed for each year separately and in a multi-environment model. The UFRGS Oat Panel showed weak population structure and has great potential to elucidate many agronomic traits in subtropical environments. Seven quantitative trait loci (QTL) associated with beta-glucan content were identified. These QTL are located on Mrg02, Mrg06, Mrg11, Mrg12, Mrg19, and Mrg20. The QTL located on Mrg02, Mrg06, and Mrg11 seem to be genomic regions syntenic with barley. The use of these QTL may be useful to accelerate the genetic progress of oat beta-glucan content in subtropical environments.