Screening for Fusarium Head Blight (FHB) Resistance in Elite Spring Barley.

Abstract

Fusarium head blight (FHB), primarily caused by Fusarium graminearum and poses a major threat to U.S. small-grain production by reducing yield and contaminating grain with harmful mycotoxins. Developing and deploying host resistance is crucial for sustainable disease management. In this study, 32 spring barley genotypes sourced from three U.S. barley breeding programs were evaluated for FHB resistance using a South Dakota F. graminearum isolate (Fg1) in field trials conducted in South Dakota over three years (2022 - 2024). Mixed-model analysis indicated that genotype effects were not significant for disease severity but were highly significant for Fusarium-damaged kernels (FDK) and deoxynivalenol (DON) accumulation, demonstrating substantial genetic variation in grain infection and toxin contamination among the evaluated genotypes. Across years, disease severity ranged from 28.12% to 70.00%. Genotypes S2M190 (39.38%), MT17M02507 (42.87%), S2M196 (46.62%), and S2M197 (46.88%) exhibited comparatively lower disease severity across seasons. In addition, S2M190 (32.50% FDK, 0.68 ppm DON) and MT17M02507 (31.25% FDK, 0.70 ppm DON) consistently showed reduced kernel damage and toxin accumulation, indicating improved tolerance to FHB infection. In contrast, Robust (66.25%) and Tradition (58.75%) exhibited higher kernel damage and DON levels. A strong positive relationship between FDK and DON further highlighted the importance of grain quality in assessing the impact of FHB infection. These results demonstrate that evaluating multiple disease-related traits is essential for identifying barley genotypes with improved tolerance to FHB and reduced mycotoxin contamination.