Carbendazim Tolerant Mutant of Gliocladium virens for the Management of Damping off of Cabbage Caused by Rhizoctonia solani Kuehn

Nine stable mutants of Gliocladium virens have been developed by UV irradiation at wavelength of 260 nm for different exposure periods (viz. , 60, 80 and 100 minutes). On the basis of higher growth parameters three of the best mutants (GvM1, GvM2 and GvM3) have been selected for further experiments. The wild strain is differed from mutant biotype in terms of colonial morphology, growth pattern, sporulation, antagonistic efficacy and fungicide tolerance. The mutant biotypes can tolerate higher concentration of carbendazim upto 50 ppm, while the wild strain fails to tolerate even 10 ppm concentration. Antagonistic potentiality of the mutants was tested against causal agent of damping off of cabbage (Rhizoctonia solani) in both in vitro and pot condition. Results were found to be more efficient for the mutants than the wild type in each parameter considered during the investigation viz. reduction in radial growth, percent inhibition of damping off, suppression of sclerotial growth and effect on growth parameters of the shoot and root length of cabbage seedlings.