The aim study of spring rapeseed cultivars reaction to autumn and winter plantings in mild cold area , a research was performed during 2005 and 2007 growing seasons in the l split plot experiment on the bases of Randomized Complete Block Design (RCBD) with four replications in Seed and Plant Improvement institute, Karaj, Iran. Treatments were included: 1-Planting season in two levels as main plots such as common planting dates autumn planting(7 October) and winter planting(6March). 2-Varieties as sub plots in 24 levels, including of RGS 003, Amica, Sarigol, Option 500, Hyola 401, Hyola 42, Hyola 60, Hyola 420, Hyola 330, Hyola 308, Kimberly, RGS 006, 19-H, Syn-3, PR-401.16, pp-401.15E, pp 308.8, pp 308.3, ORS 3150-3006, ORS 3150-3008, RG 4403, RG 405.03, RGAS 0324, RG 405.02. The results showed that simple effects of planting season and variety and also interaction effect on seed yield was significant (P<0.01). Hyola 401 in common planting date (4178 kg/ha) had the highest seed yield .But RG405.03 in winter planting (2385 and 901.1 kg/ha) had the highest seed yield respectively.
