TCAP FAC-WIN6 Elite Barley GWAS Panel QTL. II. Malting Quality QTL in Elite North American Facultative and Winter Six-Rowed Barley Identified via GWAS

Malt barley (Hordeum vulgare L.) is an economically important crop worldwide. Barley malting quality is difficult to breed for, as it is a combination of complex traits that are time consuming and expensive to phenotype. This makes marker-assisted selection-and thus quantitative trait locus (QTL) mapping-particularly appealing. We used the Oregon State University and University of Minnesota facultative and winter six-rowed barley advanced breeding lines to assemble a genomewide association studies (GWAS) panel, named the FAC-WIN6, to map malting quality QTL within our breeding programs. Winter and facultative malt barleys can be sown in fall, which makes them more sustainable in terms of soil erosion and input efficiency. The FAC-WIN6 projects are part of the Triticeae Coordinated Agricultural Project, which aims to develop sustainable barley and wheat (Triticum aestivum L.) germplasm that is robust to climate change. The FAC-WIN6 has 300 lines, with genotypic data for 5812 polymorphic single- nucleotide polymorphism markers. We conducted a 2-yr, single-location GWAS experiment for eight malting quality traits: plump grain, grain protein, and six modification traits. We report 20 malting quality QTL across seven traits. Eight of the QTL appear to be novel. For each QTL, we provide an effect estimate, a representative marker, and a candidate gene. Our results are useful for marker-assisted selection, as well as for strengthening the confidence on several QTL mapped in other barley germplasm.