In this experiment,7 inbred lines of spring cabbage were selected as the experimental materials,they differed from the characters of bolting.Two treatment were the leaf stages and the days of receiving low temperature,the leaf stages have 3 levels:the 6th,8th and 10th main leaf stage,the day of receiving low temperature have 3 levels:30,45 and 60 days.Then,the stages of bolting in these spring cabbage materials were identified.The results showed,the method,which spring cabbage materials were treated under l...