study of seed inoculation with azotobacter and psedomunas and nitrogen application timing on yield, fertilizer use efficiency and grain filling rate of sunflower

in order to study of nitrogen application time and seed inoculation with plant growth promotingrhizobacteria on yield, fertilizer use efficiency and grain filling rate of sunflower, a factorial experimentwas conducted based on randomized complete block design with three replications in research farm ofislamic azad university, ardabil branch in 2011. the first factor was time of nitrogen application inthree levels, (1/3 at 4-6 leaf stage, 1/3 at budding stage, 1/3 at flowering stage), (1/2 at 4-6 leaf stage, 1/2at budding stage), (1/4 at 4-6 leaf stage, 1/2 at budding stage, 1/4 at flowering stage) as n1, n2 and n3respectively and the second factor was seed inoculation with plant growth promoting rhizobacteria in fourlevels containing (without inoculation as control, seed inoculation with azotobacter chrocococum strain5, psedomunas putida strain 9, psedomunas putida strain 41). the results showed that maximum of grainweight, grain filling period, grain and biological yield, 1000 grain weight, number of grain per head, plantheight, head and stem diameter were obtained in nitrogen application as n2×seed inoculation withazotobacter. maximum of nitrogen use efficiency was recorded at nitrogen application as n2×seedinoculation with azotobacter and minimum of it was obtained in nitrogen application as n1× no seedinoculation. it seems that in order to increasing of grain yield, fertilizer use efficiency and grain fillingrate, can be suggested that should be applied nitrogen application time as n2×seed inoculation withazotobacter.