Association Mapping in the Nsgc 6-Row Barley NAM Population.

New genetic diversity must be incorporated into plant breeding programs if we are to continue increasing crop yield, quality, and tolerance to biotic and abiotic stress. Germplasm collections are the best source of novel genetic diversity for plant breeding, but their accessibility is limited by our ability to phenotype many accessions. The 6-row barley nested association mapping (NAM) population developed by the Triticeae Coordinated Agriculture Program (TCAP) is a bridge between the genetic diversity in the National Small Grains Collection and barley breeding programs. This population, 93 families of nearly 7,000 lines, was evaluated for heading date in 2014 in Crookston, MN, and 2015 in Saint Paul, MN and Fargo, ND. This poster presents the results of a genome wide association study (GWAS) for flowering time in the 6-row barley NAM population. Flowering time variation is critical for developing barley adapted to new growing regions and cropping systems. Additionally, we have characterized segregation distortion within and across NAM families and quantified residual heterozygosity within NAM lines. The barley NAM will be used to build on our understanding of complex, polygenic traits. These results demonstrate the utility of the germplasm, genotypic, and phenotypic resources generated during the TCAP. Ultimately, a better understanding of trait genetic architecture will increase the rate and accuracy of crop improvement.