Genome‐wide association mapping of resistance to Fusarium head blight and deoxynivalenol accumulation and haplotype analysis in a diverse barley collection

Fusarium head blight (FHB) is an economically damaging fungal disease of barley ( Hordeum vulgare L. ssp. vulgare ). Improving host resistance to FHB and the resultant accumulation of mycotoxins produced by Fusarium graminearum , such as deoxynivalenol (DON), is one of the most effective approaches for disease control and reduction of economic losses. Unfortunately, breeding for resistance to FHB in barley is difficult due to the highly quantitative nature of the trait. Numerous mapping studies have identified many quantitative trait loci (QTLs) for resistance to FHB and DON accumulation in barley; however, most contribute only small effects or are coincident with undesirable agro‐morphological traits (e.g., heading date and plant height). Genome‐wide association mapping panels have the potential to capture more QTLs than biparental mapping populations as they are comprised of diverse individuals that may possess different genes/alleles for the traits of interest, rather than just those originating from two parents. A diverse panel of 234 barley accessions was assembled, evaluated in multi‐year and multi‐environment field trials, and genotyped to identify QTL controlling FHB severity and DON concentration in grain. Multiple FHB ( n = 24) and DON ( n = 20) QTLs were detected, some of which were notably independent of QTL influencing heading date, plant height, and row type. These significant QTLs were used to generate multi‐marker haplotypes in relevant genomic regions. Haplotype‐trait associations were then tested in the panel, and the haplotype diversity was explored. Haplotype patterns at resistance QTLs were used to assess which accessions would best complement one another for use in breeding for resistance.