Shirnalli, GeetaJagadeesh Yadav, D.K.2019-09-162019-09-162015-07http://krishikosh.egranth.ac.in/handle/1/5810128427Actinomycetes are known for degradation of lignocellulose complex and antagonistic activity, but their role in Phosphours (P) solubilization activity is scanty. Hence, the present study was conducted to isolate P-solubilizing actinomycetes and test their multifunctional activities and their performance on growth and yield parameters of groundnut crop under pot culture at the Department of Agricultural Microbiology, University of Agricultural Sciences, Dharwad, Karnataka. Soil samples collected from various sources were subjected for isolation of actinomycetes. A total of 157 isolates were obtained and screened for P- solubilisation activity on Pikovskaya’s medium and modified Sperber’s media containing tri-calcium phosphate (TCP) and K2HPO4 respectively as source of P. Among the 20 isolates that exhibited P- solubisiation activity, 9 isolates were efficient in solubiilising TCP in terms of zone of solubilisation (3.0 to 15.0 mm) and release of inorganic P (7.37 to 13.14%). Among these, the isolates PSA-3, PSA-5 and PSA-7 exhibited maximum P- solubilisation activity. The production of organic acids by these isolates support the solubilisation activity. The selected 25 isolates exhibited multifunctional activities such as zinc solubilisation, hydrolysis of cellulose and starch, production of organic acids, utilization of carbon source and PGPR activities (IAA, GA, Siderophore, HCN and antagonistic activity). The three efficient P-solubilising isolates also exhibited maximum of these activities and hence tested in single and in combinations on the growth and yield parameters of groundnut plants in green house conditions. The treatment PSA-3 + PSA-5 + PSA-7 + (50% RP + 50% SSP) was the most promising treatment which was on par with the reference strain (P.striata) in terms of growth parameters, microbial activities and pod yield. Therefore, it was concluded that this treatment has potential to be used as bioinoculants in groundnut. The 16S rRNA sequence analysis showed that PSA-5 was Streptomyces badius and PSA-7 was Streptomyces bellus.ennullThesis