Abstract :
: In order to study of yield, yield attribute and dry matter accumulation of canola (Brassica napus L.) cultivars in relation to sulfur fertilizer, a split plot experiment based on randomized complete block design was conducted in 2007 at the Research Farm of Islamic Azad University, Ardabil Branch. Factors were various levels of sulfur fertilizer (0 as control, 25, 50 and 75 kg S/ha) as granular from potassium sulphate in the main plots, while canola cultivars (Fornax, Opera and Slmo) were allocated at random in the sub-plots. The results showed that various levels of sulfur fertilizer affected grain yield, plant height, harvest index, grain per pod and pod per plant significantly. Maximum of these characteristics were obtained by the plots which received 75 kg sulfur/ha. Mean comparison of treatment compound cultivar× levels of sulfur showed that maximum grain yield was obtained by the plots which were applied 75 kg S/ha with Opera cultivar and minimum of it was obtained in Slmo cultivar without of sulphur fertilizer application. Investigation of process of variances of dry matter accumulation indicated that in all of treatments, it increased slowly until 212 days after sowing and then increased rapidly till 296 days after sowing and from 296 days after sowing till harvest time, it decreased due to increasing aging of leaves and decreasing of net assimilation rate. In additional, in all of treatment compounds, dry matter accumulation in unit of area increased with increasing levels of sulfur fertilizer. The highest grain yield (1.65 t/ha) and dry matter accumulation (432.3.g/m2) was obtained in treatment compound opera cultivar with application of 75 kg S/ha. Thus, it can be suggested that opera cultivar should be applied with 75 kg S/ ha in conditions of Ardabil Plain.
