Segregation for aggressiveness and deoxynivalenol production of a population of Gibberella zeae causing head blight of wheat

Gibberella zeae is a pathogen of wheat and other small-grain cereals, causing yield losses and reducing grain quality by producing the trichothecene deoxynivalenol ( DON) which is harmful to animals and humans. One hundred and fifty three progeny from a cross between two European DON-producing isolates of G. zeae were analyzed for aggressiveness and DON production in three environments ( location-year combinations) in Germany. Aggressiveness, measured as head blight rating and relative plot yield, and DON production showed continuous distribution for each environment and across environments. There was significant ( P = 0.01) genotypic variation for all three traits. Transgressive segregants occurred for all three traits. Both repeatability estimates within an environment and heritability estimates on an entry-mean basis for head blight rating and DON production were medium to high ( 0.5-0.7). Progeny-environment interaction accounted for about 29% of the total variance for the two aggressiveness traits and 19% for DON production. The large genetic variation derived from a cross between two rather similar European parents indicates a potential for increasing fungal aggressiveness in the G. zeae population.