Isolation and Characterization of Rice Blast and Brown Spot Disease in Different Regions of Tamil Nadu, India

Rice (Oryza sativa L.) is the most important staple food crop cultivated in almost every district of Tamil Nadu. Among the rice fungal diseases, rice blast caused by Pyricularia oryzae and brown spot caused by Bipolaris oryzae are considered to be most potent threats causing major yield losses in Tamil Nadu. The present study aims in identification and characterization of rice blast and brown spot pathogen from different rice growing regions of Tamil Nadu. Three isolates of blast pathogen and five isolates of brown spot pathogen were collected and characterized based on colony morphology and conidial characters. P. oryzae and B. oryzae was identified based on cultural and morphological characters. Molecular characterization of blast and brown spot isolates were done with universal ITS primers. Pathogenicity test was carried out for all the isolates of blast and brown spot and the isolate showing maximum disease incidence was found as virulent one. The present work of morphological and molecular characterization of blast and brown spot pathogen will therefore be helpful to identify and manage the disease effectively in Tamil Nadu.