Isolation, characterization and screening of plant growth promoting activities of salt tolerant Bacillus species associated with rice rhizosphere

Eighteen salt tolerant rhizobacterial strains were isolated using nutrient agar medium from the rhizosphere of rice grown at 5 locations in Uttar Pradesh. The rhizobacterial strains were identified as Bacillus species by morphological, physiological and biochemical characters. The strains were screened for salt tolerance, indole acetic acid, siderophore, ammonia production, phosphate solubilization and antibiotic sensitivity test. Out of 18 strains, 14 strains were able to grow at 6%NaCl concentration. The colorimetric analysis showed that ETW-4 produced maximum IAA (120 mg l⁻¹) at 48 hours of incubation with optimum conditionas pH7.0 at 30ºC. The 66, 100 and 55% of strains produced siderophore, NH₃ and solubilized phosphate, respectively. All the 18 strains were tested against various concentration of tetracycline. Some of these were promising isolates and could be useful as bioinoculant for cultivation of rice under saline environment.