Effect of PGPR Biofertilizers on the Qualitative and Quantitative Yield Parameters of Wheat (Triticum aestivum)

Due to the indiscriminate use of nitrogen fertilizers, pollution caused by the use of fertilizers and high production costs, the present study examined the effects of plant growth promoting biofertilizers and nitrogen fertilizer on increasing the quality and quantity of wheat. The experiment was conducted in two-factor factorial design in three replications; (T0: as control treatment without biofertilizer T1: biofertilizer containing Azotobacter chroococcum and Azospirillum brasilense with population density of 106 cfu ml-1 of inoculum, T2: bio-fertilizer containing Azotobacter chroococcum and Azospirillum brasilense with population density of 108 cfu ml-1 of inoculum, T3: the bio-fertilizer containing Azotobacter chroococcum, Azospirillum brasilense, Pseudomonas putida and Baillus subtilis with population density of 108 cfu ml-1 of inoculum) and nitrogen fertilizer (N0: Control, N1:25, N2:50, N3:75, N4:100 kg N ha-1) in a completely randomized design. The results showed that the main effect of bio-fertilizer was related to treatment T3 which resulted respectively in 13, 20.4, 8, 19.7 and 8%increase in the 1000-grain weight, plant height, grain nitrogen content, grain yield and grain protein content in comparison to the control. In the case of main effect of chemical fertilizer levels on the mentioned parameters, the treatments 75 and 100 kg N ha-1 were the best treatments and they didnt show a significant difference (P>0.05). Regarding interactions of the treatment T3 with N3 had the highest amount and resulted respectively in 50, 51, 57.3, 81.3 and 50.5% increase in the 1000-grain weight, plant height, grain nitrogen content, grain yield and grain protein content.