Study of seed yield and seed macro elements content of three winter rapeseed varieties as affected by different nitrogen sources

In the first phase of this research, adaptability of winter rapeseed (Brassica napus L.) varieties was investigated to select high yielding rapeseed cultivars. Accordingly, two field experiments were performed in a randomized complete block design with 15 winter rapeseed varieties in three replications from 2006 to 2008 cropping seasons at experimental field of Agricultural and Natural Resources Research Center of Markazi Province, in Arak, Iran. Results showed that Licord, Modena and Okapi varieties had superiority to other cultivars, respectively. At the second phase of this research, also, two field experiments were carried out from 2008 to 2010 cropping seasons at the same site, in order to evaluate the effects of nitrogen sources on seed yield and content of macro elements in seed of selected high yielding rapeseed varieties. Experimental design was a factorial arrangement based on randomized complete block with three replications. Three rapeseed varieties (V1=Okapi, V2=Modena and V3=Licord) and three sources of nitrogen based on 150 kgN/ha (N1=Compost of Azolla, N2=50% Compost of Azolla plus 50% Urea and N3=Urea) comprised the experimental factors. Results showed that Licord variety had the highest seed yield and seed content of Sulphur. Integrated nutrition system showed superiority to other treatments for seed yield and seed content of macro nutrients such as nitrogen, phosphorus and Sulphur. But, the greatest seed potassium content was observed in N1 treatment. Results showed that integrated application of nitrogen sources increased yield and seed macro nutrients content.