Adult-Plant Resistance of Rice Cultivars to Bacterial Blight. Zhang QI, Research Fellow, International Rice Research Institute (IRRI), Los Baņos, Laguna, Philippines. T. W. Mew, Plant Pathologist, International Rice Research Institute (IRRI), Los Baņos, Laguna, Philippines. Plant Dis. 69:896-898. Accepted for publication 6 March 1985. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-896.

Selected rice cultivars expressed more resistance to bacterial blight (Xanthomonas campestris pv. oryzae) as plants developed. This resistance was comparable to adult-plant resistance to diseases of other crops. Some cultivars were resistant to four races, and others, to only one or two races. The disease severity on some cultivars gradually decreased from seedling to flag leaf, whereas in others, it showed a distinct change to a resistant reaction on a certain leaf. The leaf showing resistance varied with cultivars. Wase Aikoku 3 had adult-plant resistance to three races but seedling resistance to another. The adult-plant resistance of rice to bacterial blight appears to be race-specific.