Molecular polymorphism and virulence in Pyrenophora tritici-repentis

Abstract

Tan spot is a major leaf-spotting disease of wheat, found in all the major wheat growing areas of the world. Isolates of 'Pyrenophora tritici-repentis ', the causal fungus of this disease, are currently grouped into six races based on their ability to induce necrosis and chlorosis on a set of differential wheat cultivars/lines. The genetic variability of the pathogen and relationships among the six currently known races of 'P. tritici-repentis ' were investigated using RAPD analysis. A collection of fifty-three isolates from hexaploid and tetraploid wheats originating from Manitoba, Saskatchewan, Alberta, North Dakota, Uruguay and Algeria was used in this study. The results of this study strongly suggested that virulence is the major driving force in the variation and evolution of 'P. tritici-repentis'. (Abstract shortened by UMI.)