Phenotypic Diversity Analysis in Elaeagnus angustifolia Populations in Gansu Province, China

As a highly resistant urban ornamental plant, Elaeagnus angustifolia L. is often used in dry land, saline-alkali land shelter forest, and landscape horticulture. It is the main windbreak and sand-fixing tree species in Gansu Province, China. The special geographical and climatic environment makes the distribution and growth of E. angustifolia in Gansu Province show different degrees of difference. In order to evaluate the phenotypic diversity of E. angustifolia in different populations and its variation patterns under different geographical and climatic conditions, 35 phenotypic traits (trunk, branch, leaf, and flower related traits) of 90 plants from 10 populations in Gansu Province were measured and analyzed. The results showed the following: (1) E. angustifolia has rich phenotypic variation. The variation is greater among populations. The traits with the largest and smallest coefficients of variation were “under-branch height” and “flower diameter”, respectively. The variation in the Qilihe population was the largest, and the variation in the Ganzhou population was the smallest. The diversity of flowers and leaves is relatively higher. (2) Correlation analysis showed that most of traits were closely related. Leaf traits showed a gradient variation law dominated by altitude and precipitation. Flower traits were affected by the synergistic effects of various geographical and climatic factors. (3) The results of the principal component analysis (PCA) showed that the primary traits affecting the phenotypic diversity of E. angustifolia were leaf size and branch length among the related traits of trunk, branch, leaf, and flower. (4) Cluster analysis showed that 90 E. angustifolia plants were clustered into four clusters that were not completely clustered according to geographical distance and may be randomly affected by genotypic or environmental factors. These results will lay a foundation for further analysis of the genetic mechanism of phenotypic traits of E. angustifolia and also provide a reference for the collection, preservation, and variety improvement of E. angustifolia germplasm resources.