Poster

Gongjun Shi ¹, Cassie J Monson ¹, Alireza Poursafar ², Zerin Rafa ¹, Di Liu ¹, Andrew Friskop ¹, Andrew Green ³, Xuehui Li ³, Steven Xu ⁴, Shaobin Zhong ^2,5, and Yueqiang Leng ¹
1. Department of Plant Pathology, Microbiology and Biotechnology, North Dakota State University, Fargo, ND
2. Department of Plant Pathology, University of Minnesota, St. Paul, MN
3. Department of Plant Sciences, North Dakota State University, Fargo, ND
4. USDA-ARS, Crop Improvement and Genetics Research Unit, Western Regional Research Center, Albany, CA
5. USDA-ARS, Cereal Disease Laboratory (CDL), St. Paul, MN
Corresponding Author: Yueqiang Leng, yueqiang.leng@ndsu.edu

Shi, Gongjun

gongjun.shi@ndsu.edu

Wheat is one of the world’s most widely cultivated cereal crops, but its production is severely affected by Fusarium head blight (FHB), a fungal disease caused by Fusarium graminearum (Fg). FHB is managed primarily through an integrated strategy combining fungicide applications with resistant cultivars, of which host resistance is considered the most effective and economical measure. Although FHB resistance is generally considered durable and non-isolate-specific, emerging Fg isolates may reduce its effectiveness. In this study, we identified Fg isolates in North Dakota that were significantly more aggressive than currently predominant isolates on wheat lines with varying levels of FHB resistance, including ND 2710, Alsen, and ND VitPro. On ND VitPro, mean disease severity was 98% following infection with the emerging isolates, compared with 46% for the currently predominant isolates. Similarly, disease severity on ND 2710, a highly FHB resistant line released by NDSU, increased from 10% to 32%. Out of 71 spring wheat accessions previously reported as FHB-resistant, only five retained partial resistance under field conditions, with disease severity ranging from 36.4% to 46.25%. We further evaluated 50 wheat varieties against a highly aggressive isolate. Disease severity ranged from 25.90% to 98.75%, and only nine varieties exhibited moderate resistance, with disease severity below 40%. These findings indicate that the emerging Fg isolates may compromise the resistance conferred by Fhb1 and other established sources. We are also evaluating additional wheat germplasm to identify novel genetic resistance against the emerging isolates before these isolates become widespread. Further investigation is needed into the fitness of these isolates.

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