Evaluation of plant growth promoting potential of four rhizobacterial species for indigenous system

The aim of this work was to see whether Pseudomonas putida NWU12, Pseudomonas fluorescence NWU65, Vibrio fluvialis NWU37 and Ewingella americana NWU59 are beneficial to plants and are able to promote plant growth and development when inoculated as plant growth-promoting rhizobacteria (PGPR). The four rhizobacteria were tested in vitro for PGPR activities and on spinach and pepper in pot experiments. The inoculants are all positive for ammonia (NH3 ), catalase, hydrogen cyanide (HCN), phosphate solubilization and siderophore production. Among the inoculants, E. americana NWU59 is oxidase negative. P. putida NWU12 and P. fluorescence NWU65 are producing indole-3-acetic acid (IAA). The inoculants exhibit some PGPR activities and thus tested in the screen-house. Treatments are control (water) and the four inoculants. Rhizobacterial inoculants increase spinach (17.14%-21.43%) and pepper (15.0%-37.5%) plant heights over the control. Such inoculants have the potential of improving plant yield components and may be used as biofertilizer.