Principal Component Analysis for Major Economic Characteristics of Walnut in Northeastern Yunnan

In order to conduct comprehensive evaluations on major economic characters of walnut occurring in northeastern Yu-nan,based on correlated matrix,principal component analysis was adopted to analyze seven major economic characteristics(including average of three kinds of diameters,nut weight,shell thickness,kernel weight,kernel ratio,oil rate,and kernel weight yield per square meters of projected tree crown area) collected from 7 superior sampling strains.Three principal components,in which the rate of contribution of the accumulative variance were 92.617%,as well as their functional equations were established.Through the calculation of the values of important principal component,superior strains were ranked and compared.The theoretical results were verified with practical indices.It proofed that the principal component analysis was a suitable method for the comprehensive selection of superior walnut strain.