Effect of Different Nitrogen Levels on Yield, Yield Components and Some Quality Characteristics of Two Cultivars of Rapeseed (Brassica napus L.)

In order to evaluate the effect of different levels of nitrogen on yield، yield components and some quality characteristics of two cultivars of rapeseed، a field experiment was conducted in Dezfoul، southwest of Iran during 2011-2012. The experimental design was a split plot in a randomized complete block design with four replications. Nitrogen levels (0، 80، 160 and 240 kg ha-1) were the main-plots and two cultivars of rapeseed (Hyola 308 and Hyola 401) were the sub-plots. The results revealed that the highest number of pods per plant and seeds per pod were obtained at 240 kg N ha-1. The highest oil percentage was obtained with the zero kg ha-1 N fertilizer (control). Hyola 401 cultivar was proven superior، in terms of different parameters، to Hyola 308. The regression analysis showed that the highest grain yield could be obtained from Hyola 308 (1998 kgha-1) and Hyola 401 (2375 kgha-1) using 225 and 228 kg N ha-1، respectively. Since the grain yield and quality of Hyola 401 were found to be higher than Hayola 308، Hyola 401 seems to have better ability to absorb and transport nitrogen and therefore produce more grain yield.