Effect of inoculation with Azotobacter chroococcum on wheat yield and seed quality

An investigation has been organized to study the effect of wheat seed inoculation (the cultivars Renesansa and Zlatka) with Azotobacter chroococcum, strain 86 (2-5x CFU 10(8) ml(-1)). Experiments were conducted under field conditions, on a chernozem soil. The effectiveness of inoculation on wheat seed quality (germination energy and percentage), yield and 1000-seed weight was shown to depend on the amount of applied urea (50, 100 and 200 kg ha(-1) and nonfertilized control) and wheat cultivar. A. chroococcum treatment, depending on variety and fertilizer treatment, increased the energy of germination by 1 to 9% and seed viability by 2 to 8%. Negative effects on seed germination energy and percentage were found in the case of the cultivar Zlatka, in the variant with 100 kg urea ha(-1). The largest increase in 1000-seed weight was obtained in the case of the cultivar Renesansa, in the variant without N application (16%). A. chroococcum inoculation increased the seed yield of both cultivars in the variant without urea application and with 50 kg ha(-1) of urea. The highest yield increase (74%) was registered in the case of the cultivar Zlatka when inoculated and treated with 50 kg ha(-1) of urea. All effects, except the yield, were low in the case of the cultivar Zlatka