Diversity and antagonistic potential of Bacillus spp. associated to the rhizosphere of tomato for the management of Rhizoctonia solani

Bacillus spp. has emerged as the most effective alternative to synthetic chemical fungicides. To get a better insight in the antagonistic potential of Bacillus strains, rhizospheric soil samples of healthy tomato plants from Indo-gangetic plain regions of India were analysed. A total of 108 Bacillus strains were obtained from preliminary screening. Potent strains identified on the basis of in vitro antagonistic and biochemical assays were subjected to diversity analysis using 16S-rDNA, BOX and ERIC-PCR. Furthermore, the four best performing antagonistic Bacillus strains under in vitro plant growth promotion and antagonistic assay were selected for pot experiment. In field study, Bacillus amyloliquefaciens MB101 and Bacillus subtilis MB14 showed drastic reduction in disease index by 55.7 and 41.74% with significant elevation in fruit yield up to 220 and 184 qha(-1), respectively. The present study was successful in selecting effective Bacillus strains by performing phenotypic and genotypic characterisation of Bacillus strains that can be used as an integral component of integrated disease management of tomato root rot and damping-off.