Heading character of Chinese cabbage planted in spring is related with bolting date,leaf differentiation speed(LDS)and foliage;A good spring cultivar with tight head should have late bolting date,much foliage and appropriate leaf differentiation speed.Coefficient of correlation between bolting date and flower bud differentiation critical date(FBDCD)reached significance level,FBDCD could replace bolting date,as an index of early growing stage for the selection of Lateboltign materials.CTK,Spm,Spd and Put in ...