Author(s):

Ritika Narayan and Naresh Chandra Gupta

Abstract: Azospirillum spp. is of worldwide distribution prevalent in tropical, sub-tropical and temperate climatic conditions and has been isolated from the rhizosphere of a variety of tropical and sub-tropical non-leguminous crops. Keeping these points in view a study was conducted during Rabi and Kharif 2016-17 in the Department of Soil Science and Agricultural Chemistry, Birsa Agricultural University, Ranchi, Jharkhand to screen out the presence of Azospirillum in rhizosphere of various non-leguminous crops and to characterize the isolates on the basis of cultural and physiological behaviours. On the basis of pH range (4.0-5.5), 54 soil samples were tentatively selected out of 100 samples for investigation. From the study conducted, presence of Azospirillum in rhizosphere of lower pH was confirmed. 6 colonies out of 54 colonies were translucent while the rest were opaque in terms of degree of opacity. Amount of growth ranged from large to slight. Growth pattern of colonies were found filiform and beaded in 41 and 13 colonies respectively. Physiological investigation revealed that Azospirillum isolates were microaerophilic in relation to free oxygen i.e., developed white pellicles 1-2 mm below the surface of semi-solid Okon’s media after 48 hours of incubation at 35°C. All isolates were positive for catalase reaction but responded negative for Indole production and Gelatin liquification test. 15 isolates out of 54 were able to hydrolyse starch. 20 isolates responded positive to nitrate reduction test. 19 isolates out of 54 required biotin for their growth. Pigmentation was reported in 13 isolates after 48 hours of incubation at 35°C on Okon’s solid agar media.

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