Comparison of Yield and Physiological Indices of Spring Cultivars of Oliseed Rape Species

In order to evaluate the yield and physiological indices of 13 spring cultivars of rapeseed, an experiment was conducted in 2007 growing season at Agriculture and Natural Resources Research Station of Trogh, Mashhad. These cultivars were from three rapessed species, Brassica napus, Brassica rapa and Brassica juncea. The experimental design was randomized complete block with four replications. Results showed considerable differences among yield, TDM and LAI of cultivars. Seed yield of B. napus cultivars was more than that of B. rapa cultivars. With exception of RGR, cultivars of B. napus had more value of physiological indices than cultivars of B. rapa. A maximum TDM was obtained during growth season after 1105.3 GDD at pod filling stage. A maximum GAI was observed with receiving 744.7 GDD at flowering stage and after that lessening trend of GAI was gradually acquired with a mild slope. A maximum CGR was obtained after 867.9 GDD at end of flowering. Based on the results, it was concluded that TDM and LAI had more correlation coefficients than other physiological indices both within and among species