Identification of Shading Tolerance in Thirty Brassica campestri sssp.chinensis Varieties

Thirty varieties of non-heading Chinese cabbage were treated with low light intensityand classified with the cluster analysis by three indices,change of dry weight,change of leaf thick and change of chl.a/b.The thirty varieties were divided into three basic types,tolerant,middle-tolerant and susceptible.Among these varieties,nine were susceptible,fifteen were middle-tolerant,and six were tolerant.The results showed that the correlation of three indices were significant.Comparatively,the varieties Shulü,Zhengda Kangreqing No.3,Reyou No.2,Kangre No.605,Aiwang and Huawang were more tolerant.