Isolation and Characterization of Azospirillum sp. from Paddy Field Soil, Thanjavur District, Tamil Nadu

The present study focused on isolation and characterization of Azospirillum sp. from paddy field soils of Thanjavur (Dt), Tamil Nadu. The physico-chemical characteristics of the soil samples were analysed by using standard methods. Totally nine native strains of Azospirillum were isolated. Among the nine isolated strains three strains were belonging to Azospirillum amazonense and six strains belonging to A. brasilense. Morphological and physiological properties were performed all the isolates. The effect of different concentration of NaCl and antibiotic sensitivity test also analyzed. All the isolates were possessed N2 fixing capability, the highest level of nitrogen fixation was done by A. brasilense TPS05, which fixes nitrogen at a rate of 11.2 mg N/g. Inoculation of A. brasilense TPS05 on paddy ADT 36 in pot culture produced the maximum number of tillers, roots, leaves, leaf length and breadth, shoot and root length and grain yield.