Study of seed inoculation with Azotobacter and Psedomunas and nitrogen application timing on yield, fertilizer use efficiency and grain filling rate of sunflower (Helianthus annus L.)

In order to study of nitrogen application time and seed inoculation with plant growth promoting rhizobacteria on yield، fertilizer use efficiency and grain filling rate of sunflower، a factorial experiment was conducted based on randomized complete block design with three replications in research farm of Islamic Azad University، Ardabil branch in 2011. The first factor was time of nitrogen application in three 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، 1/2 at budding stage)، (1/4 at 4-6 leaf stage، 1/2 at budding stage، 1/4 at flowering stage) as N1، N2 and N3 respectively and the second factor was seed inoculation with plant growth promoting rhizobacteria in four levels containing (without inoculation as control، seed inoculation with Azotobacter chrocococum strain 5، Psedomunas putida strain 9، Psedomunas putida strain 41). The results showed that maximum of grain weight، grain filling period، grain and biological yield، 1000 grain weight، number of grain per head، plant height، head and stem diameter were obtained in nitrogen application as N2×seed inoculation with Azotobacter. Maximum of nitrogen use efficiency was recorded at nitrogen application as N2×seed inoculation with Azotobacter and minimum of it was obtained in nitrogen application as N × no seed inoculation. It seems that in order to increasing of grain yield، fertilizer use efficiency and grain filling rate، can be suggested that should be applied nitrogen application time as N2×seed inoculation with Azotobacter.