Investigation the effect of plant growth promoting rhizobacteria (PGPR) on growth, yield and dry matter remobilization in barley

In order to survey the impact of plant growth promoting rhizobacteria and nitrogen fertilizer on growth, yield and remobilization of photosynthetic dry matter in barley, a two-year factorial experiment based on randomized complete block design with three replicates was carried out on barley cultivar LB-IRAN, at the research farm of the Islamic Azad University, Ardabil branch, Ardabil, Iran, in two consecutive years of 2019 and 2020 cropping years. First factor included five nitrogen levels: 0 (control), 25, 50, 75, 100 kg/ha net nitrogen, and second factor contained grain inoculations with four bacteria: no inoculation (control), Azotobacter crococcum strain 5, Azospirillum lipoferum strain of, and combination of the two mentioned bacteria. Fertilization was performed at planting, tillering, and grain filling stages. Results revealed that most of the studied traits were significant. Nitrogen rate increment resulted in the higher rates of the above mentioned traits so that 100 kg/ha nitrogen significantly showed the highest amounts while control caused the lowest ones. Combined treatment of the bacteria resulted in the higher rates compared to the single bacteria, and control showed the lowest amounts. Also, it was observed that application of 100 kg/ha nitrogen on Azotobacter crococcum strain 5, and Azospirillum lipoferum strain of resulted in the lowest rate of dry matter remobilization from stem and whole plant to the grain, and contribution of dry matter remobilization from stem and whole plant to the grain while, control treatments of nitrogen and of PGPRs caused the highest rates.