Genome-wide association mapping for kernel shape and its association with beta-glucan content in oats

Kernel shape and beta-glucan content are important attributes for oat (Avena sativa L.) millers. The identification of genomic regions controlling these traits, as well as their effect on phenotype, will enable rapid gain from selection. The objectives of this study were (a) to identify the genomic regions associated with kernel shape in an oat panel adapted to subtropical environments and (b) to clarify the relationship between kernel shape and beta-glucan content in oat. An elite oat panel comprising 406 inbred lines was assessed in Londrina and Eldorado do Sul, Southern Brazil. Genome-wide association analyses were performed for each environment separately and also in a multi-environment analysis. Phenotypic and genetic correlation coefficients were estimated between kernel shape traits and beta-glucan content. Genomic regions influencing kernel length were identified on Mrg06, Mrg21, and Mrg24. Kernel width and kernel thickness were genetically correlated and shared a quantitative trait locus, located on Mrg13 of the oat consensus map. Phenotypic and genetic correlations were found between kernel shape traits and beta-glucan content, indicating a negative relationship between kernel width or kernel thickness and beta-glucan content. Oat breeding programs that aim to maintain minimum levels of beta-glucan for nutrition and minimum kernel widths for milling will need to screen for both traits; otherwise, indirect selection will lead to unfavorable results. However, the negative correlation was not too strong (-0.4), suggesting that improvement for both traits can be made simultaneously.