Recovery of Additional Flat mutants of Cryphonectria parasitica

Abstract

Additional mutants with the phenotype have been recovered from hypovirulent (dsRNA containing) strains of the chestnut blight fungus, Cryphonectria parasitica. The nuclear type of these strains was one that has been used in many laboratory and field tests and crossing experiments. Singleconidial isolates were recovered, and some of these were crossed with a standard strain. As reported previously, the phenotype segregated among the progeny as if controlled by a single nuclear gene, and single-ascospore isolates with flat phenotypes were not virulent in American chestnut trees.