MORPHOLOGICAL AND PATHOLOGICAL VARIABILITY OF DIFFERENT ISOLATES OF Rhizoctonia solani KUHN CAUSING SHEATH BLIGHT DISEASE OF RICE

Sheath blight disease, caused by Rhizoctonia solani, is an important fungal disease of rice (Oryza sativa L.). Morphological and pathogenic variability of 24 isolates of R. solani, collected from different locations of Prayagraj (U.P.), were studied. Growth of R. solani was observed in different colours like, light yellow, whitish yellow, pale yellow, light cream yellow, yellow and cream yellow. Growth of this pathogen was good and very fast as in some isolates. Sclerotia were found mostly thin and their colours were brown, dark brown as well as blackish brown. Different distribution patterns were observed in sclerotia production viz., central, peripheral and scattered. Number of sclerotia was ranged between 53.67-164.00 and sclerotia weight was ranged between 0.116-0.373 g. Maximum numbers of affected/dead tillers (6.33), number of lesions (9.0), mean lesion length (19.0 cm) and relative lesion height (45.37 cm) was recorded with RS_U22, RS_U49, RS_U7 and RS_U22, respectively.