Efficacy of Pseudomonas fluorescens strain Pf-4-R for the suppression of sheath blight in rice cv. Pusa 1121
2011
Kumar, Adesh | Kaura, Guraprīta | Singh, Pushpinder Paul | Hunjan, Mandeep Singh
Many rhizobacteria including fluorescent Pseudomonads have been known to suppress pathogenic microflora in rice crop besides promoting plant growth. In this study, we isolated sixty four (64) isolates from the rhizosphere of rice and wheat and evaluated their efficacy against Rhizoctonia solani causing sheath blight of rice. These isolates were identified as P. fluorescens based on phenotypic characteristics and using rDNA ITS region (16S-23S) and further classified on the basis of production of diacetyl phluoroglucinol (DAPG) and phl gene locus. Among different P. fluorescens isolates, isolate Pf-4-R exhibited the maximum inhibitory activity against R. solani in vitro. The same isolate was further formulated as talc based formulation (cfu/g of 9.6 X 10⁹) and tested in field in sheath blight sick plots. It was observed that seed treatment followed by seedling root priming (formulation @15g/l water) gave maximum sheath blight suppression (73.50%) as compared to seed treatment alone (59.82%). The same treatment also resulted in better plant vigour as evident from more plant biomass (mean dry weight of 60g/plant) over control (mean dry weight of 40g/plant). Rhizosphere persistence of Pf-4-R was about 90 days after transplanting in sheath blight sick plots.
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