Screening of potassium solubilizing bacteria (KSB) for plant growth promotionalactivity

Thirty rhizobacterial isolates belongs to genera Bacillus and Pseudomonas were isolated and evaluated for their plant growth promotional activity. The amount of potassium released into the liquid medium by potassium solubilizing isolates ranged from 2.41 to 44.49 μg/ml, while the amount of Pi released ranged from 5.72 to 12.27 per cent. Among the isolates, KSB 33 released maximum amount of K (44.49 μg/ml) and Pi (12.27%) respectively. Most of the isolates were capable of producing plant growth promoting substances, and the amounts of IAA and GA produced by them ranged from 1.10 to 16.50 and 0.60 to 3.29 μg/25 ml broth respectively.