Objective In order to select superior families and individual plants which is suitable for planting in Nanjing and surrounding areas for providing a theoretical basis for the oriented silviculture of Cyclocarya paliurus plantations.

Method The 3.5-year old germplasm resources of C. paliurus trees were comprehensively evaluated in this study. The 31 families of C. paliurus trees were used as test materials to determine the traits of growth and the leaf contents of total flavonoid, triterpenoid, and polyphenol. And cluster analysis and entropy method were used to screen superior families and individual trees based on the variations in traits.

ResultsSignificant variations were observed in tree height, diameter at the base, and the leaf contents of total flavonoid, triterpenoid and polyphenol among different families. Hierarchical cluster analysis showed that the 31 families of C. paliurus were classified into four distinct groups. The C. paliurus families in cluster 1, cluster 2 and cluster 3 could be recommended as the families for high accumulation of total triterpenoid, total polyphenol, and total flavonoid, respectively. In contrast, the families in cluster 4 showed poor performance in all measured metabolites. Seven superior families (GXJZS7#、GZSQ12#、GXLS26#、HNYS2#、AHQLF13#、SCMC31# and GXJZS1#) of C. paliurus were preliminary selected for the accumulation of target secondary metabolites using entropy method. Within the seven superior families, all the trees were further assessed, and eleven superior individuals were selected.

Conclusion There are significant variations in growth and leaf secondary metabolites among the tested germplasm resources, showing a great potential for the selecting and breeding of C. paliurus. Based on the comprehensive assessment, seven superior families and eleven excellent individuals are selected for further test and future application.