International Journal of Plant & Soil Science

The present investigation was carried out during 2021-22 at Acharya Narendra Deva University of Agriculture & Technology, Kumarganj, Ayodhya (Uttar Pradesh). Results revealed that phenotypic characterization of plant growth promoting microbial isolates from rice rhizosphere and phyllosphere have significant effects on physicochemical properties of soil. On the other hand, microbial isolates have a significant effect on microbial biomass carbon (MBC) and total protein content of the soil. Applying microbial isolates has a positive impact on microbial population in terms of total rhizospheric bacterial population (0.77 - 8.4×10⁶ cfu g^-1 soil). Whereas, fungal population (1.0 – 51.0 ×10³ sfu g^-1 and actinomycetes (1.7- 97 ×10³ cfu g^-1 of soil). Whereas, total number of phyllospheric bacterial population of rice plant leaves and clumps were 0.53- 6.4×10⁶ cfu g^-1, leaf fungal population 1.0- 73 ×10² sfu g^-1, leaf Actinomycetes population 0.67- 1.2 ×10³ cfu g^-1. A total of 6 bacterial stains, 2 Actinomycetes and 3 fungal strains were isolated from the rhizospheric soil. Similarly, 4 bacterial stains, 2 Actinomycetes and 2 fungal strains were also isolated from the phyllosphere of the rice field by serial dilution effect on plating techniques. Plant growth promoting (PGP) traits were evaluated. The highest IAA (Indole Acetic Acid) production (23.75μg ml^-1) was recorded under the RRS5 (Rice Rhizospheric Sample 5) and followed by RRS3 which was produced at 18.76 μgml^-1. The isolated microorganisms can be used as an effective bio inoculant either individually or in different combinations for the formulation of different multi potent biofertilizers for plant growth promotion substances as well as control of plant diseases in rice crop.