STUDIES ON CHARACTERISTICS OF XANTHOMONAS ORYZAE ISOLATES ASSOCIATED WITH RICE CROP

Abstract

Rice Bacterial Leaf Blight (BLB) is considered the most imperative disease among various dangerous maladies of rice in Pakistan. There is no any reliable source of resistance against this disease. Moreover, pathogen has a vast diversity in its population. So, first and most important step for its control is pathogen identification and characterization. Therefore, present studies were carried out for surveillance of disease and to collect disease specimens from Hyderabad and Tando-Muhammad Khan (TMK) Districts. Associated pathogen was isolated from collected samples by direct plating method. Fourteen cultures were purified by streaking method and were characterized on the basis of colony morphology, cell morphology and gram staining. The colonies were found to be large, medium and small. Their shapes were filamentous, irregular and circular. They were found to be raised, undulate, entire and convex showing pale yellow, yellow, off white, reddish and creamy color and surface of most of the colonies was observed to be smooth