V. SRINIVAS, S. PRATYUSHA AND S. GOPALAKRISHNAN*

International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru 502324, Telangana.

ABSTRACT

A total of 19 strains of Streptomyces sp. viz., CAI-13, CAI-17, CAI-21, CAI-24, CAI-26, CAI-68, CAI-78, CAI-85, CAI-

93, CAI-121, CAI-127, CAI-140, CAI-155, KAI-26, KAI-27, KAI-32, KAI-90, KAI-180 and MMA-32 were earlier reported by

us as plant growth-promoters in chickpea, pigeonpea, sorghum, rice, pearl millet, tomato and chili. In the present investigation, the 19 strains of Streptomyces sp. were evaluated for development of a long term, eco-friendly and inexpensive formulation using different carrier materials such as peat, lignite, talc and talc + starch. Streptomyces strains were individually grown and inoculated into the four selected carrier materials and stored in the refrigerator at 4oC. Samples were collected at the end of every month and tested for their viability and shelf life by plate count method for 12 months. All the 19 Streptomyces strains were viable and grown in all the tested carrier materials, however, peat inoculants showed greater viability and maintained stable colony forming units when compared talc, lignite, and talc + starch inoculants. It is concluded that peat formulation is best suited for mass multiplying the selected 19 Streptomyces strains..

KEYWORDS: Plant Growth Promoting (PGP) microbes, bio-formulations, Streptomyces sp.