Assessment of virulence of bacterial blight (Xanthomonas oryzae pv oryzae (Ishiyama) Swings et aJ.) of rice (Oryza sativa L.) and identification of genotypes with high resistance

Abstract

Bacterial blight (BB) of rice is the second most devastating disease that causes substantial yield loss. Study of pathogenic variability and identification of resistance genes are key factors in breeding against this disease. Five isolates collected from different parts of northwestern India were screened against eight aromatic genotypes to identify variability in virulence. Most virulent isolate was used to screen forty eight rice genotypes collected from different regions of Bihar, Jharkhand and UP to identify resistant sources. All the aromatic genotypes were found to be either moderately or highly susceptible against all the isolates with significant differences in disease progress. Isolate 5 was found to be most virulent against the aromatic lines while isolate 4 was least virulent. Isolate 5 was used to screen forty-eight genotypes. Thirteen lines showed high resistance against the highly virulent isolate. Inheritance of resistance in these rice lines should, therefore, be investigated further.