RESPONSE OF SOME AGRONOMIC CHARACTERISTIC OF CANOLA (BRASSICA NAPUS L.) TO NITROGEN FERTILIZER AND SOWING DATE

To study effects of nitrogen fertilizer and sowing date on some agronomic traits of canola cultivars, a factorial split plot experiment based on randomized complete block design with four replications was conducted during growing season 2013 – 2014 at the Research Farm of Gonbadkavus University, Iran. Treatments were four canola (Brassica napus L) cultivars (C1=Hayola 401, C2=Zarfam, C3= Hayola 308, and C4=RGS003), two planting dates (D1=17 Nonvember and, D2=28 December) and three levels of nitrogen fertilizers (N1=0, N2=%50 of recommended fertilizer, N3=%100 recommended fertilizer). In this study the treatment of nitrogen fertilizer levels and planting dates were asseigned to main plots and canola cultivars to sub plots. The results of analysis of variance showed that the interaction effects between nitrogen fertilizer × planting were significant at 0.01 probability level on all evaluated traits. Interaction of planting date × cultivar effects on all yield components except seed per silique were also significantly. The fertilizer × cultivar interaction did not affect yield components significantly. The highest yield, 4.2 t/ha, was produced by the open pollinated cultivar of RGS003 using %100 recommended rate of nitrogen fertilizer at sowing date of 17 November, which represents a high potential of this cultivar under this nutrients level and sowing date.