Isolation and Characterization of Azospirillum Isolates from Soil and Their Effect on Growth and Yield of Wheat (Triticum aestivum L.) under Different Levels of Nitrogen Fertilizer

This study involved isolation of Azospirillum from soils that are different in texture from Aswan governorate. Also, study the response of wheat (Triticum aestivum L.) to inoculation with the isolated Azospirillum strain (M-1, M-2 and M-3) in presence of different levels of nitrogen fertilization (40, 60 and 80 kg N/fed.) was tested in field experiments in the two seasons 2014/2015 and 2015/2016. Results of the morphological, cultural and physiological characteristics of the three Azospirillum strains (M-1, M-2 and M-3) indicated that they belong to Azospirillum brasilense. Wheat seed inoculation with any of the isolated Azospirillum strains (M-1, M-2 and M-3) induced highly significant increases in all measured growth parameters as well as in total and grain yields and % N in grains. Strains M-1and M-3 were more simulative than M-2 producing the highest total and grain yields. The two interacting factors (inoculation X Nfertilization level) showed most pronounced mutual effects at the lowest level of 40 kg N/feddan with any of the tested strains compared with the uninoculated treatment. Azospirillum strain M-1was the most reactive at all N-levels. The results also indicate that wheat inoculation with effective Azospirillum strain could save between 20-40 Kg N-fertilizer /feddan.

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