Evaluation of Gamma-induced mutants of Trichoderma harzianum for biological control of charcoal rot of melon (Macrophomina phaseolina) in laboratory and greenhouse conditions

Macrophomina phaseolina is one of the major yield limiting factors of melons in tropical and subtropical regions. For eco-friendly and effective management of the disease, 24 gamma induced mutants from Trichoderma harzianum 65 isolate were evaluated against three isolates of the pathogen representing three different isolates of M. phaseolina from Khorasan (isolate 1), Garmsar (isolate 2) and Khuzestan (isolate 3) isolates. The isolates of Trichoderma (mutants and wild type) were evaluated against the pathogen in dual culture and through production of volatile and non-volatile inhibitors. Maximum growth inhibition was observed in Th1, Th4, Th15, Th9 and Th22 mutants after three days. In greenhouse evaluation against M. phaseolina (isolate 1) among the inoculated treatments minimum infected plant percentage observed in Th9 treatment by 28% disease reduction as compared to infected control and among the uninoculated treatments Th1and Th9 mutants resulted in maximum growth of roots and shoots as compared to uninfected control in melon plants. These mutants are introduced as potential candidates against pathogens M. Phaseolina. The results proved that gamma-mutagenesis by improvement of the antagonistic properties of T. harzianum 65 can be useful for the biocontrol of soil borne plant pathogens such as Macrophomina phaseolina.