Response of Two Wheat Varieties to Partial Replacement of Recommended Nitrogen Fertilizer by Bacterial Inoculations

TWO FIELD trials were carried out at the Agricultural Production and Research Station, National Research Centre, El Nubaria Province, El Behira Governorate, Egypt, during the two successive winter seasons 2006-2007 and 2007-2008, to study growth characteristics, yield and yield attributes of two wheat varieties, i.e. Sakha-93 and Sakha-94, to partial replacement of recommended nitrogen fertilizer by bacterial inoculation (Azospirillum or Nitrobein). The plant height, number and dry weight of spikes/nr and straw yield/feddan showed substantial varietial differences. While, the dual application of biofertilizers and recommended nitrogen fertilizer increased almost all growth characteristics, yield and yield components, this increase was significance with the studied characters except, plant height at 90 days after sowing and blades area (cm2) at 90 and 120 days after sowing and number of spikelets /spike, number of grains /spikelet, seed index, harvest index and grain protein content. Seed inoculation with either Azospirillum or Nitrobein and 50 % of recommended nitrogen fertilizer showed the lowest values of the aforementioned traits compared with the other treatments. The effect of the interaction between varietial differences and nitrogen fertilization treatments on growth characteristics, yield and yield components are not significant in most studied characters except number of spikes/m2 in the two growth samples and dry weight of spikes/m2, grain, straw and biological yield /feddan