大白菜为二年生作物,正常条件下一年只能繁殖一代。培育一个自交系一般需要6-8年,育成一个品种一般需要8—10年,从而影响育种工作的进展速度。多年来育种工作者为解决这一矛盾进行了各种研究,如南繁北育,冬季温室来种或利用组织培养等手段。但一般一年也只能繁殖1.5—2代。近年 Chinese cabbage is a biennial crop, which can only breed one generation a year under normal conditions. It usually takes 6-8 years to breed an inbred line and 8-10 years to grow a breed, thus affecting the progress of breeding work. Over the years breeding workers to solve this contradiction conducted a variety of studies, such as South Fanfugai, winter greenhouse to species or the use of tissue culture and other means. But generally only 1.5-2 generations of breeding a year. in recent years