Pathogenic Races of Pyricularia grisea Isolated from Sasanishiki Multiline Cultivars in 1995 and 1996 and their Pathogenic Variants

Abstract

Three hundred eleven isolates of Pyricularia grisea were obtained from panicle blast lesions in mixtures of rice cv. Sasanishiki and its nine isogenic lines in 1995 and 1996. And their pathogenic races were identified using Japanese differential rice cultivars. Although five races were identified, most of the isolates were belonged to race 007. Pathogenicity of blast fungus reisolated from leaf blast lesions formed on incompatible differential rice cultivars was also investigated. Pathogenicity of thirty reisolated strains to the differential cultivars was different from that of the original isolates, and nine races were newly identified. The ‘super race’ was not isolated from the mixtures.