Isolation, identification of Azospirillum and its inoculation effects on maize (Zea mays L.)

Abstract

Among the fifty samples, white undulating pellicle in N free malate semi-solid medium was produced by allthe isolates. On the malate agar media with NH4Cl, typical isolation colonies were circular, small to medium, greenish-whitewith smooth texture and were opaque. All the isolates were spiral shaped and gram negative. Based on the utilization ofcarbon sources, thirty isolates were tentatively identified as Azospirillum brasilense and twenty isolates were tentativelyidentified as Azospirillum amazonense. Selected isolates were tested for their antifungal activity against Exserohilumturcicum under in vitro condition and antifungal activity of isolates was determined by the decreased diameter of fungalgrowth compared to the diameter of the control fungal growth. ACDAZS-35 showed the highest percentage inhibition of85.56%. The results of pot trials showed that inoculation of maize seeds with Azospirillum isolates ACDAZS-09,ACDAZS-30, ACDAZS-35, ACDAZS-47 along with a reference Azospirillum spp. ACD-15 at different nitrogenlevels showed a significant increase in number of leaves over the uninoculated control. It was found that maximumnumber of leaves, SPAD values, N content were observed in ACDAZS-9 inoculated with 50 % N application at 30 and60 DAS. The present study revealed that the selected Azospirillum inoculants were capable of increasing the growthof maize plants and can save 25 % of inorganic nitrogen application