Fusarium head blight (FHB) is a devastating disease in barley because grain becomes unusable for food, feed, forage or malt due to the production of mycotoxins, for example - deoxynivalenol (DON). In barley, only partial resistance to FHB is currently available and much of that resistance is due to phenological or morphological avoidance. Increased levels of DON not only spoil grain but aid in pathogen infection. Our research aims to genetically dissect the variation in DON in a barley biparental mapping population. We evaluated a population of 117 RILs from a cross between Bearpaw and Pinnacle. Although the parents were not significantly different for FHB severity, they did vary for the presence of DON, with Bearpaw tending to have less.  Through initial screening of the population at Eastern Agriculture Research Centre, Montana and DON testing at the University of Minnesota, we observed variation in DON among the RILs. The population was screened using the 50K SNP chip and a genetic linkage map of 4434 SNP markers built.  Preliminary QTL analysis identified 4 QTL associated with variation in DON on chromosomes 4, 5, 6 and 7, none of which coincide with heading date QTL on chromosomes 1, 2 and 5. Three of the alleles from the Bearpaw parent were associated with decreased DON at QTL on chromosomes 4,6 and 7, but the Bearpaw allele was associated with increased DON on chromosome 5. On examining the QTL regions, we found known disease resistance genes underlying QTLs on chromosomes 5 and 6. We will re-evaluate the experiment in a replicated trail in 2025. By pyramiding alleles associated with decrease in DON, we hope to decrease the impact of FHB for barley growers and end-users.

Key words: Fusarium head blight, deoxynivalenol (DON), barley, Fusarium graminearum, QTL, SNP marker