Abstract：The ITS sequences of 18 different types of Brassica rapa were amplified by PCR and sequenced,and then the NJ tree was constructed by ITS sequences to analyze the variations of ITS sequence.The results show that the sequences of the ITS of Brassica rapa are very conservative,and no variations exist between different types.Brassica rapa has variations with other species of Brassica respectively.The ITS sequences have variations among the species of Brassica,and the different type materials of the basic species of Brassica have no variations.However,those of the complicate species have variations and the ITS sequences tend to the putative parents of the U-triangle respectively.
