VIEW ARTICLE

Genetics

Variability of Xanthomonas oryzae: Specificity in Infection of Rice Differentials. T. W. Mew, The International Rice Research Institute, Los Baņos, Laguna, The Philippines; C. M. Vera Cruz, The International Rice Research Institute, Los Baņos, Laguna, The Philippines. Phytopathology 69:152-155. Accepted for publication 1 August 1978. Copyright 1979 The American Phytopathological Society. DOI: 10.1094/Phyto-69-152.

Rice cultivars with specific resistance to bacterial blight showed distinct differential reactions to isolates of Xanthomonas oryzae. Lesion length caused by 80 isolates collected from different regions in the Philippines was determined by the different genes for resistance of the cultivars. Specificity in infection of the different rices suggested three different virulence groups or strains. A major group included those that infected IR8 or rice that carries no genes for resistance to bacterial blight. Specificity of the isolates in differential infection of the rice also was shown in infection of rice of different ages planted in the greenhouse or in the growth room under conditions most favorable for plant development.