一、前言 萝卜(Raphanus. sativus L.)是我国人民喜爱的一种蔬菜。在蔬菜周年供应中占有一定的地位。由于北京夏季气候条件影响,从八月中旬到九月中旬形成大约40天左右夏淡季、不仅鲜菜供应不足,而且品种单调,这是北京市八、九月淡季蔬菜供应中多年来存在的老问题。为此选育能 I. Introduction Radish (Raphanus sativus L.) is a favorite vegetable of our people. In the annual supply of vegetables occupy a certain position. Due to the impact of Beijing’s summer climatic conditions, about 40 days of summer and light seasons are formed from mid-August to mid-September. Not only is the supply of fresh vegetables insufficient, but also the varieties are monotonous. This is the reason that Beijing has existed for many years in the supply of off-season vegetables in August and September problem. Breeding for this