甘蓝为十字花科芸薹属2年生植物,半耐寒,喜凉爽气候,根系主要分布在30厘米的土壤中,气温20～25℃时适于外叶生长。甘蓝为长日照植物,第一年形成叶球,翌年在2～6℃的低温条件下完成春化,遇长日照条件,就抽薹开花、结果。为了提高露地杂交制种的产量,经我们多年实验,应把握好以下几个环节。 Brassica oleracea Brassica biennial plants, semi-hardy, hi cool climate, the roots are mainly distributed in 30 cm of soil, the temperature 20 ~ 25 ℃ for the outer leaf growth. Cabbage is a long-day plant, the first year the formation of leaf ball, the following year at 2 ~ 6 ℃ under vernalization conditions to complete the vernalization, in case of long sunshine conditions, the bolting flowering, the result. In order to improve the yield of hybrids in open field, after years of experiments, we should grasp the following aspects.