Comparing winter rapeseed cultivars (Brassica napus L.) according to yield and yield components in cold regions of Iran

In order to study the adaptation and grain yield of 24 winter rapeseed cultivars, in cold regions of Iran, field experiments were carried out using randomized block design with three replications in four Agricultural Research Stations (Karaj, Zanjan, Hamedan and Shahr-e-Kord) in two successive cropping season (2000-2002). The results showed that the number of pods per plant was one of the important agronomic characteristics which implies the adaptation of winter rapeseed cultivars to cold regions. From 24 winter rapeseed cultivers studied, only six cultivars (Regent, Cobra, Orkan, Alice, Eural, Colvert and parade) were superior for crown diameter, rosette height and plant dry weight at roset stage. Orkan and Parade produced higher grain yield (3850 t/ha) and were determined as more suitable cultivars for regions with severe winter cold and late spring frost.