Diversity among the Salt Tolerant Rhizobacteria of Tungabhadra Command Area

Pure cultures of 450 salt tolerant rhizobacterial isolates were prepared by isolating them from saline rhizospheric soils of Tungabhadra command area of north eastern Karnataka on nutrient agar medium supplemented with 1, 3, 6, 9 and 12 per cent salt and all the isolates could able to grow at 12 per cent salt. Among which, 20 isolates were selected and subjected to morphological, biochemical examinations which exhibited the presence of great diversity, as 14 isolates tested gram negative rods and rest found gram positive cocci, with the 14 isolate having motility. All the bacterium tested negative for starch hydrolysis, nitrate reduction and citrate utilization test and positive for catalase test, 11 were negative for urease test, 10 positive for gelatine liquefaction, 13 positive for H2S production and 2 positive for protease test. The in vitro screening of these salt tolerant isolates for their plant growth promotional activity revealed the identification of GP-21 as efficient P- solubilizer, GS-36- nitrogen fixer (0.018 per cent) and MP-63 as IAA (21.2 g/50 ml) producer.