1选地,隔离选择无霜期120d左右的冷凉区,地势较为平坦、土质肥沃疏松,排灌方便、集中连片的地块作为制种田。前茬以小麦等禾谷类作物最好,油菜茬次之,严禁与油葵连作,必须保证制种田方园3km以内无同类作物种植,以确保杂交油葵一代种子的纯度。 1 election, the choice of frost-free period of about 120d cold area, the terrain is relatively flat, loose soil fertility, irrigation and drainage convenience, concentrated contiguous plots as a system of farming. Crops such as wheat and other cereal crops before the best, followed by rapeseed, oil sunflower is strictly prohibited even crop production system square must be within 3km of no crop planting, to ensure the purity of the first generation of hybrid sunflower seed.