Application of principal component analysis and projection pursuit to superior individual selection of Tripterygium wilfordii.

The selection standards for growth traits of superior individual trees of Tripterygium wilfordii were studied by means of the methods of Principal Component Analysis and Projection Pursuit respectively.The results showed that both of these two methods were applicable for the superior individual tree selection of T.wilfordii.The method of Principal Component Analysis was more appropriate to be adopted by taking coverage,length and the basal diameter of the main rattans as the main selection indices,while the method of Projection Pursuit was more suitable to be applied by taking the length of main rattans,the basal diameter and the coverage as the main selection indices.The length of the main rattans and the basal diameter were determined as the main selection indices for superior trees on wild T.wilfordii by comparing the advantages and disadvantages of the two methods.20 superior individual trees were selected based on the comprehensive evaluation,and it was found out that the superior individual trees selected by the two different selection methods were exactly the same.