Mandalay University Research Journal, Vol. 4, 2013 211 ISOLATION AND IDENTIFICATION OF Azospirillum spp. FROM THE ROOTS OF MAIZE Zea mays Pioneer Kyaw Myo Naing 1 , Thant Zin 2 Abstract The nitrogen fixing bacteria Azospirillum were isolated from the roots of maize (Zea mays) cultivated in the field of Tada-U Town, Mandalay Region. Three species of Azospirillum were isolated by using selective medium. Identification of isolated bacteria was based on the growth of differential media, colony morphology, basic chemical staining reactions and motility. Isolated bacteria were nitrogen fixer and could be useful as source for preparation of biofertilizer. Key words: Azospirillum, nitrogen fixing bacteria, maize, Tada-U Town Introduction Biological nitrogen fixation is the key to sustain agricultural productivity through the application of biofertilizers in the field (Saikia et al., 2007). With the concept of plant growth- promoting-bacteria gaining worldwide acceptance, a large number of bacterial strains have been isolated and evaluated primarily for promotion of plant growth (Bashan, 1998). A variety of free-living microorganisms are capable of fixing nitrogen. Among these free-living forms of eubacteria are members of the genus Azotobacter (Nester et al., 1998) and the genus Azospirillum (Jolly et al., 2010). Azospirillum species belong to the facultative endophytic diazotroph groups which colonize the surface and the interior of roots. They are microaerophilic nitrogen-fixing, Gram negative rods and often associated with roots of cereals and grasses (Grifoni et al., 1995). Azospirillum, soil bacteria, have been isolated from the rhizosphere of a wide range of plant species, including commercially important crops such as maize, rice, wheat and sorghum (Okon and Vanderleyden, 1997). These bacteria may fix N 2 at rates up to 2 kg per hectare per day in association with maize (Von Bulow and Döbereiner, 1975). In the current agriculture, nitrogen is a limiting nutrient for growth and yield of crops (Panneerselvam and Kanimozhi, 2010). Inorganic or mineral fertilizer N is the rich and readily available source of N as plant nutrient contributing to environmental hazards in a variety of way (Jolly et al., 2010). Some of these problems can be tackled by use of biofertilizers, which are natural, beneficial and ecologically friendly (Bahrani et al., 2010). By taking the information on the possibility of obtaining the nitrogen fixing bacteria from the roots of maize, this work has been carried out to isolate and identify the Azospirillum species from the roots of maize, to investigate the colony morphology of these bacteria through culture in the different media and to determine the cell characters and staining reactions of isolated bacteria. Materials and Methods Study Period The present work was performed during the period from June, 2010 to February, 2011. Collection Site Maize plants (Zea mays) were collected from the cultivated fields of Tada-U Town, Mandalay Region, located at 21° 48' N and 95° 58' E (Plate I. A and B). 1 = Assistant Lecturer, Dr., Zoology Department, University of Mandalay 2 = Professor, Dr., Zoology Department, University of Mandalay