Effect of Seed Inoculation with Plant Growth Promoting Rhizobacteria (PGPR) Affected by Different Levels of Nitrogen and Phosphorus Fertilizers on the Yield and Some Physiological Parameters of Barley (Hordeum vulgar L.)

In order to investigate the effects of plant growth promoting rhizobacteria inoculation on growth criteria and yield of spring barley in different levels of nitrogen and phosphorus fertilizers, an experimental was conducted in two years at the Research Farm of Islamic Azad University, Ardabil branch during two growing seasons of 2009-2010 and 2010-2011 years. Experiment was conducted as Factorial split-plot design with three replications. The combination of nitrogen fertilizer in three levels (0, 40 and 80 kg N ha-1 as urea) and phosphorus fertilizer (0, 30 and 60 kg P2O5 ha-1) were factorialy assigned to the main plots and seed inoculation with plant growth promoting rhizobacteria in four levels (no inoculation, seed inoculation with Azotobacter chorchorum strain 5, Azosprilium lipoferum strain OF and combination of Azotobacter + Azosprilium) were assigned to the subplots. The results showed that with increasing of nitrogen and phosphor rates and seed inoculionat with plant growth promoting rhizobacteria, all of growth indices such as total dry matter, crop growth rate, relative growth rate and leaf area index were increased. Also, seed inoculation with both of Azospirillum and Azetobacter in all of sampling stages in growth indices was more than control (no seed inoculation). Maximum grain yield and leaf dry weight were obtained in highest rates of nitrogen and phosphor fertilizers with seed inoculation with both of Azosprilium and Azotobacter and minimum of they were obtained in no application of them.