*2.1. Plant Material*

The study comprised 299 genotypes from the HWWAMP. These genotypes included varieties released since the 1940s and represent existing germplasm of the hard winter wheat growing regions of the US, including Colorado, Kansas, Michigan, Montana, Nebraska, North Dakota, Oklahoma, South Dakota, and Texas [42,43]. The HWWAMP represents diverse germplasm with unique haplotypes as compared to a breeding program nursery from a single breeding program. A list of the genotypes comprising the HWWAMP along with their pedigrees and geographical origin has been published previously in the supplementary material of Guttieri et al. [44]. Many studies in bread wheat rely on using this HWWAMP for mapping genomic regions important for a trait, and subsequently validate those marker-trait associations in their own breeding programs prior to using the markers for marker-assisted selection. The HWWAMP has been successfully used for mapping genomic regions for various biotic and abiotic traits including wheat spot blotch resistance [45], drought resistance [46], Cd accumulation [44,47], and bacterial leaf streak resistance [48]. All genotypes in HWWAMP were grown at Lincoln, NE in 2018 in 1 m<sup>2</sup> plots with fungicide application, and the harvested seeds from these genotypes were used in this study.
