evaluation of some agronomic traits of rapeseed (brassica napus l.) as affected by different sulphur application rates

this experiment was carried out in factorial arrangement based on randomized complete block design with three replications in agricultural and natural resources research center of markazi province, arak (iran) during 2008-2009 growing season. three application rates of sulphur (s1=0, s2= 40 and s3=80 kg/ha) and three rapeseed varieties (okapi, modena and licord) comprised the experimental factors. s2 treatment had superiority over other treatments for some characteristics such as seed and oil yield. licord had the highest siliques per plant, 1000-seed weight, seed and oil yield. the combination of licord × 40 kg/ha s showed the highest siliques per main branch, siliques per plant, 1000-seed weight and seed yield. correlation between seed yield and siliques per main branch (r=0.47**), siliques per plant (r=0.57**), 1000-seed weight (r=0.69**) was positive and significant. in addition there was positive and significant correlation between oil yield and siliques per main branch (r=0.51**), siliques per plant (r=0.48**), 1000-seed weight (r=0.50**) and seed yield (r=0.90**). it can be concluded that siliques per main branch, siliques per plant, 1000-seed weight have greater influence on seed and oil yield increment in comparison with other yield components. in this research 40 kg/ha s and licord cultivar had superiority to other treatments for seed yield enhancement per unit area.