Abstract :
ABSTRACT: In order to study the effects of seed inoculation with plant growth promoting rhizobacteria (PGPR) on grain yield and some growth indices in safflower (Carthamus tinctories L.), a split plot experiment based on randomized complete block design with three replications was conducted in 2011 at the Research Farm of Islamic Azad Univewrsity, Ardabili branch. Treatments were: seed inoculation with plant growth promoting rhizobacteria at four levels (without seed inoculation as control, seed inoculation with Azotobacter chroococcum strain 5, Azosprilium lipoferum strain OF, Pseudomonas strain 186 ) in the sub plots and nitrogen fertilizer rates as urea in four levels (zero as control, 60, 120 and 180 kg/ha) in the main plots. Means comparison of treatment compound nitrogen fertilizer rates× inoculation seed with plant growth promoting rhizobacteria showed that maximum grain yield was obtained in seed inoculation with Pseudomonas strain 186× application of 180 kg/ha and minimum of it was obtained in non application of fertilizer×inoculation seed with PGPR. Investigation of variances of dry matter accumulation indicated that in all of treatments, it increased slowly until 40 days after sowing and then increased rapidly till 100 days after sowing. From 100 days after sowing till harvest time (110 days after sowing), it decreased due to increasing aging of leaves and decreasing of crop growth rate and relative growth rate. In additional, in all of treatment compounds, the highest dry matter accumulation in unit of area was obtained at seed inoculation with Pseudomonas strain 186. Seed inoculation with PGPR also significantly increased the crop growth rate and the maximum of it was observed when was applied 180 kg /ha × inoculation seed with Pseudomonas. In all of treatment compounds, CGR increased slowly until 60-70 days after sowing and then decreased slowly till 65-70 DAS. From 65-70 days after sowing till harvest time, it decreased rapidly due to increasing aging of leaves. Means comparison showed that maximum grain yield (1940.4 kg/ha) was obtained in application of 180 kg N/ha × seed inoculation with Pseudomonas strain 186 and minimum of it was in without seed inoculation with PGPR and nitrogen fertilizer. Thus, it can be suggested that in order to increasing of grain yield and some growth indices such as total dry matter, crop growth rate and relative growth rate, 180 kg N/ha×seed inoculation with Pseudomonas strain 186 should be applied in conditions of experiment.
