The Chemotypes 3ADON, 15ADON, NIV, and NX-2 of Fusarium graminearum Vary in Aggressiveness on Wheat

Non-Peer ReviewedThe aggressiveness of Fusarium graminearum chemotypes was assessed in a greenhouse experiment on spring wheat genotypes that varied in resistance to Fusarium head blight (FHB). Fifteen isolates (five 3ADON, five 15ADON, three NIV, and two NX-2) of F. graminearum isolated from Saskatchewan wheat fields were evaluated using point inoculation (Type II resistance assay). Evaluation was on three wheat genotypes assessed as resistant, moderately resistant, and susceptible to FHB and near-isogenic lines (NILs) in the CDC Go (moderately susceptible) background, carrying Fhb quantitative trait locus (QTL) in four combinations: Fhb1, Fhb2, Fhb5, and Fhb1+Fhb2+Fhb5. All four F. graminearum chemotypes were pathogenic on wheat and varied in aggressiveness. Disease severity (FHB) of 3ADON, 15ADON, NIV, and NX-2 isolates differed, with 3ADON (29.7 ± 3.6) and 15ADON (22.4 ± 2.9) isolates more aggressive than NIV (16.7 ± 2.8) , and NX-2 (16.2 ± 3.1) isolates. Significant differences were observed for mycotoxin accumulation among chemotypes, which was highest for 3ADON (14.1 ± 2.26 ppm). There was no interaction between chemotype and wheat line for disease severity or mycotoxin accumulation. Link to Video Presentation: https://youtu.be/KW7imkOeU5