Isolation and screening of maize Growth-Promoting Rhizobacteria for the production of biofertilizer: a case study of the Hauts Bassins in Burkina Faso

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Résumé

Mineral fertilizers are widely used for maize production in West Africa. However, these fertilizers are not affordable for most of the local farmers. This study was carried out to isolate plant growth-promoting Rhizobacteria (PGPR), which could be used as low-cost biofertilizers. Two farming sites practicing biological agriculture were selected in the “Hauts bassins” region of Burkina Faso. The farming practices were recorded, and rhizospheric soils were sampled. The PGPR strains were isolated from soil and purified using specific media. Furthermore, they were tested for plant growth-promoting capability, including N 2 fixation, HCN, NH 3 , exopolysaccharides, and Indole-3-Acetic Acid production. Principal Component Analysis (PCA) was performed to identify the most promising strains, which were tested for the germination of maize variety FBC6. Then, the most promising strains were submitted to presumptive characterization. A total of 235 strains of PGPR were isolated, of which 10 rhizobacteria (493A, 7134A, 341A, 3123A, 59A, 668A, 614B, 3127A, 415A, and 412A) were able to simultaneously produce at least four plant growth-promoting properties. These strains significantly improved the radicle, the coleoptile lengths, the seminal root numbers, and the root biomass of the maize (p < 0.001). Root moisture content was significantly (p < 0.001) improved by the strains 7143A, 3123A, and 412A. However, the germination rates were not significantly increased. The five most promotive strains were affiliated with the genera Burkholderia, Paenibacillus, and Sphingomonas . These promising strains could be used as an alternative to the use of mineral fertilization for maize production.

Mots-clés

Rhizospheric Soils, NPK-Urea, Maize, Cultivation Practices, PGPR