Vol. 12, Issue 5 (2023)

Under present investigation PGPR isolates were isolated from different rhizotic zones of maize based intercropping system by using different media from twelve different site of Bihar including diara belt. Laboratory and pot experiments were conducted at Deptt. of Microbiology, F.B.S. & H, RAU, Pusa. PGPR isolates are coded for Azospirillum spp. as AZS₁ to AZS₁₂, Azotobacter spp. as AZT₁ to AZT₁₂, Pseudomonas spp. as PSD₁ to PSD_`12 and P-solubilizing bacteria spp. as PSB₁ to PSB₁₂. These isolates were screened on the basis of seed germination, production of IAA, P-solubilization activity, antifungal activity, and nitrogenase activity for the formulation of microbial consortium.

Nitrogenase activity (3.15 mole C₂H₄/g/hr), mycorrhizal infection (80%), MPN of Azospirillum spp. (0.35 x 10⁵/g) and population of P-solubilization bacteria spp. (10.50 x CFU x 10⁵/g) were found maximum in isolates from Hazipur (diara belt) while population of Azotobacter spp. was maximum in Danapur (diara belt). Among the isolates, PSD₆ exhibited very high antifungal activity (% inhibition 83.83). Isolate AZT₄ showed maximum response against root and shoot length (6.75 and 4.72 cm) and very high response against Nitrogenase activity. Azospirillum spp. isolate AZS₆ showed best response against seed germination test and nitrogenase activity (114.48 mole C₂H₄/mg protein/hr) PSB₄ isolate was identified for maximum response against seed germination test and also showed very high P-solubilization activity (75.67%).

Keeping in view of experimental findings, PGPRs of diara belt are extremely diversified and perform well in stress condition. They are also competitive in nature and efficient in nitrogen fixing, P-solubilization and producing plant growth hormones. Microbial consortium improves crop growth and increase biomass production. Hence, it may be concluded that PGPRs (PSD₆ , AZS₆ ,& AZT₄ are best microbial Inoculant in all respect than that of others which is very significant not only in growth parameters but also in maintaining soil health for sustainable crop production.