２０００年河间市大田向日葵虽然前期长相喜人，可是后期产量却不高，据调查主要是空壳秕粒多造成的。其产生的主要原因是： 一、品种不对路 有的品种本身不孕花多达１０％～１５％；同时有些品种混杂退化严重，致使植株高矮不一，花期长短有异，造成授粉不良。 二、播期不适 2000 Hetian City, Daejeon sunflower Although the early looks gratifying, but the late output is not high, according to the survey is mainly caused by the shell and more. The main reasons for its production are: First, the varieties are not on the road Some varieties of their own infertility as much as 10% to 15%; at the same time, some varieties of mixed degeneration seriously, resulting in different plant height, flowering length differences, resulting in poor pollination. Second, sowing discomfort