Potential of Bioinoculants Based on Plant Growth-Promoting Rhizobacteria (PGPR) Isolated in the Municipality of N’Zérékoré (Guinea) for the in Vitro Germination of Maize and Rice
Against a backdrop of steadily declining soil fertility, falling crop productivity, dependence on imported chemical inputs, and mounting pressures on food security, Guinea’s agricultural sector must rethink its production models by adopting endogenous, sustainable, and agroecological solutions. Against this backdrop, the objective of this study was to evaluate the potential of bioinoculants based on indigenous rhizobacteria isolated from the rhizosphere soils of the urban municipality of N’Zérékoré on the in vitro germination of maize and rice. The experimental approach involved collecting soil samples from the rhizosphere of maize and rice plants. Next, rhizobacteria strains were isolated, identified, and characterized using Gram staining, catalase, and tests for the production of ammonia, indole acetic acid, hydrogen cyanide, etc. The identified strains were then evaluated for their agronomic performance through an in vitro germination test. To do this, maize and rice seeds, which had been previously disinfected, were treated by soaking in bioinoculants based on the isolated rhizobacteria at bacterial concentrations of approximately 108 CFU/mL and then transferred to Petri dishes for in vitro germination at 30？C for seven days. The results show that all strains produced catalase, indoleacetic acid (IAA), and ammonia. The Ri2, M5, Ri1, and M4 strains significantly improved several growth parameters, including root length, seedling length, and vigor index in maize and rice, as well as seedling and root weight in maize. Although no statistically significant differences were observed in germination rates, these strains showed the best values compared to the control. These results confirm the ability of local rhizobacteria to play a central role in improving the germination of rice and maize seeds. This study also opens up concrete prospects for establishing local bioinoculant production chains that generate added value and are adapted to the soil and climate conditions of Forest Guinea.
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