大白菜的杂种一代,国外在五十年代就开始在生产上应用,到六十年代后期有些国家已占新育成品种的100%,生产上几乎都用杂种一代.可是这些杂种一代皆由自交不亲和系制种的.鉴于利用自交不亲和系生产杂种一代,存在着亲本的保持和繁殖较为困难,故我国有不少单位于七十年代初开始选 The hybrid generation of Chinese cabbage began to be used in production in the 1950s in foreign countries, and some countries accounted for 100% of newly-bred varieties in the late 1960s, almost all of which used hybrid generation in their production. Inconsistency of seed production in view of the use of self-incompatible lines to produce hybrid generation, there is the parental maintenance and reproduction more difficult, so many units in our country in the early seventies began to vote