Isolation and Characterization of Indigenous Rizobacteria from Shallot (<i>Allium ascalonicum</i>, L) Rizosphere as PGPR Agents

Abstract The one microorganisms that function as biological agents and many colonize the rhizosphere of plants is rhizobacteria. The study aimed to isolate and characterize rhizobacteria from the shallot rhizosphere that function as Plant Growth Promoting Rhizobacteria (PGPR) agents. Soil samples were taken from the root zone of shallot plants in Glumpang Baroe and Blang Bambie villages, Pidie, Aceh Province, Indonesia. The study employed quantitative and qualitative descriptive analysis methods, utilizing the serial dilution technique.. Macroscopic, microscopic (gram test), and phosphate solubilization test parameters were observed. Macroscopically, there was a diversity of rhizobacterial isolates based on shape, color, edge and elevation. Based on gram test, Twenty rhizobacterial isolates were found in samples from Glumpang Baro (GB) (7 gram positive and 13 gram negative isolates), from Blang Bambie (BB) 11 isolates (7 gram positive and 4 gram negative isolates). Nineteen isolates from GB and eleven isolates from BB were able to dissolve phosphate, only one GB isolate was not able to. The rhizobacterial isolate (GB 6/1) produced the highest PSI (2.80) and the lowest isolate (GB 7/2) (2.33), while the rhizobacterial isolate (BB 4/2) produced the highest PSI value (2.73) and the lowest (2.40) in isolates (BB 4/1 and BB 7/3).