Effect of Nutritional and Physiological Factors on Growth and Sclerotial Formation of Rhizoctonia Bataticola (Tan B.) Butler Isolates

Experiment was carried out to see the effect of nutritional and physiological factors on growth and sclerotial formation of Rhizoctonia bataticola isolates. Out of six media, tested, PDA supported the growth and sclerotial formation of Rhizoctonia bataticola followed by Czapek's dox, Richard's, Oat meal and peptone agar media. Sclerotial formation on malt extract medium was moderate with poor myceEa growth whereas,- peptone agar medium induced rare or no sclerotial formation. Among six carbon sources, highest growth was obtained in dextrose followed by sucrose, mannitol, starch, maltose and cellulose. Sclerotial production in cellulose was maximum followed by dextrose, sucrose, maltose, starch while, it was minimum in mannitol. Sodium nitrate proved better nitrogen source for growth and sclerotial formation than ammonium nitrate. All isolates gave maximum mycelial growth at 35°C and minimum at 20°C. SclerotiaJ formation was also better at 35°C and nil or. rare at 20°C and 40°C. There was no significant difference in radial growth in isolates at pH range 5 to 9. Although pH 7.0 was suitable for the growth of pathogen.