Genetic variation and covariation for aggressiveness, deoxynivalenol production and fungal colonization among progeny of Gibberella zeae in wheat

Gibberella zeae (anamorph Fusarium graminearum) causes head blight of cereals and contaminates grains with mycotoxins such as deoxynivalenol (DON). To determine the correlations among aggressiveness traits, fungal colonization and DON production, 50 progeny from a segregating population of G. zeae were inoculated onto a susceptible winter wheat cultivar in three field environments (year-location combinations). Aggressiveness traits were measured as head-blight rating and plot yield relative to noninoculated plots. Fungal colonization, measured as Fusarium exoantigen (ExAg) content, and DON production were analysed with two ELISA formats. Disease severity was moderate to high based on head-blight rating and relative plot yield. Fusarium ExAg content and DON production ranged from 0.26-1.41 units and from 4.18-43.70 mg kg⁻¹, respectively. Significant (P = 0.01) genotypic variation was found for all traits. Heritability for Fusarium ExAg content was rather low because of high progeny-environment interaction and error. DON/Fusarium ExAg ratio did not vary significantly (P > 0.1) among progeny. Correlation between DON production and Fusarium ExAg content across environments was high (r = 0.8, P = 0.01), but no covariation existed between aggressiveness traits and DON/Fusarium ExAg content ratio.