Abstract

Twenty five isolates of Rhizoctonia solani were isolated from infected rice fields from different agro-ecological regions of West Bengal. Cellulase and pectinase activities of the isolates were detected using carboxymethylcellulose (CMC) and pectin agar media, respectively. Diameter of the clearing zones on the respective media represented the level of enzyme activity of each isolate. Mycelial protein, carbohydrate and phenol contents were also recorded. The virulence of the isolates was studied on the rice cultivar (MTU 7029) under greenhouse conditions. Correlation of the biochemical constituents and enzyme activity with virulence of the R. solani isolates was performed. Pectinase activity found to be the important factor could predict the variation in the virulence of R. solani strains up to seventy six percent.

Key words: Pectinase, mycelial protein, carbohydrate, virulence, Rhizoctonia solani.