Effect of Different Plant Growth Promotion Bacteria (Azotobacter, Azospirillum) on Growth Parameters and Yield of Field Maize

Soil beneficial microorganisms such as plant growth promoting rhizobacteria (PGPR) are able to enhance plant growth. The research was conducted using a randomized complete block design as split plot factorial with three factors (nutrient management, Azospirillum and Azotobacter strains). In this experiment the effect of Azospirillum and Azotobacter inoculation on yield and yield components of maize was evaluated in a field trial. Azotobacter levels were A0: no inoculation, A1: Azotobacter sp. Strain5، A2: Azotobacter chroococcum DSM2286 and Azospirillum levels were Z0: no inoculation, Z1: Azospirillum sp. Strain21, Z2: Azospirillum lipoferum DSM 1691, Z3: Azospirillum brasilense DSM1690. Results of this study showed inoculation with Azotobacter had significant effect on grain yield, stem and total dry weight, plant height and leaf area as well as 100 seed weight. The same results were obtained with Azospirillum inoculation. The interaction between two bacteria on grain yield, 100 seed weight, number of seed per ear, ear diameter, stem, leaf and total dry weight, plant height, leaf area and nitrogen uptake in seed were significant.