The effect of different levels of sulfur and Thiobacillus fertilizer on yield, yield components and oil percentage of sunflower in Gonbad area

In order to study the effect of sulfur and Thiobacillus on some qualitative and quantitative traits of sunflower (cv. Hisun 25), an experiment was conducted as factorial based on Randomized Complete Block Design with three replications on research farm of the Gonbad Kavous University in 2013. The sulfur rate factor was in four levels: 0, 200, 400 and 600 kg sulfur per hectare and Thiobacillus bacteria factor was in four levels: 0, 10, 20 and 30 kg Thiobacillus per hectare. Results showed that the sulfur had a significant effect on plant height, 1000-seed weight and seed yield at 5% and on plant dry weight, oil percentage and oil yield at 1% probability. Effect of Thiobacillus on 1000-seed weight and seed yield at 5% and on plant height, plant dry weight, oil percentage and oil yield at 1% was significant. The maximum values of all traits were obtained from the highest amounts of sulfur and Thiobacillus. The highest plant height, 1000-seed weight, plant dry weight, seed yield, oil percentage and oil yield obtained from consumption of 600 kg S/ha. The maximum plant height, 1000-seed weight, plant dry weight, seed yield, oil percentage and oil yield belonged to consumption of 30 kg Thiobacillus/ha. The results of this study showed that effect of sulfur and Thiobacillus on some morphological traits, seed yield and yield components was less than percentage and yield of oil. This maybe has happened because of the sulfur role in oil production.