Isolation and Identification of Cyanobacteria and Its Plant Growth Promoting Efficacy using Maize (Zea mays) Seed Germination Experiment
Cyanobacteria are valuable biofertilizers due to their ability to improve nutrient availability and stimulate plant growth. This study investigated cyanobacterial isolates from maize rhizosphere soils collected from 16 maize-growing areas in Central, Oromia, and Southern Ethiopia. Cyanobacteria were isolated from maize rhizosphere soils using BG-11 culture medium and characterized through morphological and biochemical analyses. A total of 132 cyanobacterial isolates were obtained and screened for nitrogen-fixing ability on nitrogen-free BG-11 medium, phosphate-solubilizing activity on Pikovskaya’s agar, and siderophore production using the Chrome Azurol S (CAS) assay.A total Nine isolates showing both nitrogen fixation and phosphate solubilization were further characterized. All selected isolates were positive for catalase and oxidase activities, while eight produced siderophores. The germination promoting effects of cyanobacterial extracts were assessed using a Petri plate germination assay. Among them, isolate Tj~8~ recorded the highest phosphate-solubilization index (2.68). Seed germination experiments on maize varieties BH546 and BH547 revealed significantly higher germination rates in inoculated treatments than in the control. Tj~8~ produced the best individual performance, whereas the consortium Gt~12~ + Tj~8~ achieved the highest germination percentages. These findings suggest that selected cyanobacterial isolates have strong potential for development as eco-friendly biofertilizers for sustainable maize production.