Determining Plant Growth Promoting Effect of Potential PGPR (plant growth promoting rhizobacteria) Strains.

Determining Plant Growth Promoting Effect of Potential PGPR (plant growth promoting rhizobacteria) Strains

This experiment was conducted to test the hypothesis that the bacterial strains N-6, N-12 and X are Plant Growth Promoting Rhizobacteria (PGPR). PGPR can promote plant growth through phytohormone excretion, nitrogen fixation, compound solubilizing mechanisms, or displacement of detrimental organisms (biocontrol). The bacterial strains, X, N-12 and N-6, were isolated previously from the rhizosphere of plants and selected for their potential PGPR characteristics. N-12 and N-6, primarily identified to be Paenibacillus spp/ Bacillus mucilaginosous, showed potent silicate-solubilizing activity.   The strain X has not been tested previously but exhibited biocontrol characteristics in a petri dish which could possibly characterize it as a plant growth promoting rhizobacteria. To test for plant growth promoting ability of the strains, thirty-six maize seeds were inoculated with each strain. They were planted in sterile soil placed in pots and allowed to grow outdoors for twenty-five days before cropping for measurement. Preliminary data received seven days prior to cropping did reveal N-12 to significantly promote plant growth. However, the results of 25 days after inoculation revealed that inoculation with the three bacteria did not promote growth in a statistically significant manner.  Further experimentation will still be required to test the are plant growth promoting activities of N12, N6 and X. All strains if proven PGPR could be mass produced as biofertilizer to increase growth of crops inoculated. Bacterial strain X has potential as an antibiotic as well as a biofertilizer because of its biocontrol abilities.