Abstract:
Identification of phytobeneficial properties of rhizobacteria is an important
strategy to screen plant growth promoting rhizobacteria (PGPR) that can be
utilized to increase crop yield and thereby fulfill the increasing demand for
global food production. In this study rhizobacteria were isolated from the
rhizosphere of Silk banana (Musa acuminate × Musa balbisiana) growing
in Matara and Galle area and assessed their potential of phytobeneficial
properties. Out of the 32 rhizobacterial isolates, 17 isolates including 4
endorhizosphere bacteria were identified as plant growth promoting
rhizobacteria based on their phytobeneficial properties. Among them, 13
isolates possessed indole-3-acetic acid production ability and 9 isolates
possessed phosphate solubilizing ability. Among the top 5 isolates with
highest potential to produce indole-3-acetic acid, 2 were shown biofilm
formation ability. According to the preliminary investigation, 6 isolates
showed the ability to fix atmospheric nitrogen. Following established
biochemical tests, the characterized plant growth enhancing rhizobacteria
were identified as the members of genera Staphylococcus, Streptomyces,
Bacillus, Pseudomonas and Azotobacter. Isolates belong to genera
Staphylococcus and Streptomyces had high potentials in plant growth
promoting properties than the other isolates. Inoculation of seeds of
selected legume species with these selected plant growth promoting isolates
resulted in significant enhancement in seed germination (60% increment)
and significant enhancement in root and hypocotyl length (3.74 fold
increment) compared to control experiment. It is important to focus our
consideration for the development of biofertilizers using these selected
rhizobacterial strains as they have shown multiple growth promoting
characteristics.