Poster # 403
Shiwarttan K. Gupt, Bikash Ghimire, Alfredo D. Martinez-Espinoza, Jake C. Fountain, James W. Buck
1. Department of Plant Pathology, Griffin Campus, University of Georgia, Griffin, GA
Corresponding author: J. W. Buck; jwbuck@uga.edu
Gupt, Shiwarttan Kumar
Fusarium head blight (FHB), primarily caused by Fusarium graminearum, poses a major threat to wheat and barley production. Although Fusarium poae is increasingly reported in cereal-growing regions worldwide, its pathogenic
potential in U.S. wheat and barley remains underexplored. We compared the pathogenicity and aggressiveness of four F. poae isolates (GA18W 2.1.6, GA18W 5.2.4, GA18W 6.1.4, GA19W 13.2.1II) and one reference F. graminearum isolate (GA18W 3.1.4) across seven cultivars (three soft red winter wheat, two durum wheat, two barley) classified as moderately resistant or susceptible. Greenhouse evaluations were conducted in 2021, 2022, and 2024 using single
floret inoculation (SFI) and direct spray (DS). Disease severity (SEV), Fusarium damaged kernels (FDK), thousand kernel weight (TKW), and mycotoxins (DON, HT-2/T-2) were assessed. Main effects of isolate, cultivar, and inoculation method were significant for SEV, FDK, and TKW (P < 0.0001). After finding no significant differences among the four F. poae
isolates for SEV, FDK, or TKW, we pooled the F. poae data to report species-level summaries. Across cultivars, methods, and years, F. graminearum GA18W 3.1.4 produced higher SEV (47–63%) and FDK (54–76%) and reduced TKW (to 18 g) relative to pooled F. poae (SEV 14–36%; FDK 32–56%; TKW up to 24 g), with the greatest impacts in durum wheat. Preliminary toxin data showed DON frequently >40 µg g⁻¹ with F. graminearum. HT-2/T-2 was sporadically detected only in durum wheat inoculated with F. poae (maximum 2,300 µg kg⁻¹ in ‘Divide’ with GA18W 6.1.4). These results
show that F. poae can contribute to FHB in U.S. small-grain cereals and support including this species in resistance screening.
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