Poster

Sujan Gautam¹, Stephen N. Wegulo ¹, Niki McMaster² and David G. Schmale III ²
1. Department of Plant Pathology, University of Nebraska–Lincoln, Lincoln, NE, USA
2.School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, USA *
Corresponding Author: PH: 402 472-8735; Email: swegulo2@unl.edu

Gautam, Sujan

sgautam6@huskers.unl.edu

Fusarium head blight (FHB), caused by Fusarium graminearum, is a major wheat disease that reduces yield and contaminates grain with the mycotoxin deoxynivalenol (DON). Understanding variation in aggressiveness and DON production in local pathogen populations is valuable in assessing disease risk. This greenhouse study evaluated six Nebraska, F. graminearum isolates on two spring wheat cultivars, CV2398 (susceptible) and Glenn (moderately resistant), using a split-plot randomized complete block design with 4 replications and 2 runs. 15–20 spikes per experimental unit were inoculated with a 5 × 10⁵ spores ml⁻¹ suspension from six isolates. FHB severity was assessed at 7, 14, and 21 days post-inoculation to calculate mean severity and area under the disease progress curve (AUDPC), and harvested grain was analyzed for DON by GC-MS. ANOVA indicated highly significant effects (P < 0.001) of cultivar, isolate, and their interaction on mean severity and AUDPC, and significant (P ≤ 0.05) isolate and cultivar × isolate effects on DON. Across cultivars, isolates differed in aggressiveness and DON production; more aggressive isolates had higher DON, while the least aggressive produced lower DON. Linear regression of DON on AUDPC was significant (R² = 0.58, P < 0.001), with a positive association between aggressiveness and DON within each cultivar. These findings reveal variability in aggressiveness and DON production among isolates across cultivars, highlighting the need to combine host resistance with knowledge of local, contemporary pathogen populations for effective FHB management.

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