Abstract:
Objective A popular ornamental tree for landscaping, Handroanthus impetiginosus tends to differ in phenotypic traits between individual plants. This study aimed to collect information on the resources for selection and cultivation.
Method Twenty different phenotypic traits of 62 H. impetiginosus plants collected from 12 population groups in 6 cities of Guangdong Province were used to calculate coefficient of variation (CV) and Shannon diversity index as well as conduct correlation, principal component, and clustering analysis.
Result The CVs of these phenotypic traits varied between 13.53%–59.13%, while the Shannon diversity index between 0.79–4.08. High CV and diversity index connotated richness in phenotype diversity of the species. Their qualitative indices differentiated more greatly than quantitative ones, and the qualitative indices correlated with one another. Among the 6 principal components in the 20 traits, the indices associated with leaf, including width, area, length, petiolule length, and petiole length, were the major contributors which were followed by those related to the branch and trunk diameters at breast height and under branch height. A hierarchical clustering analysis divided the 62 H. impetiginosus plants into 4 population groups based on their phenotypic characteristics.
Conclusion H. impetiginosus was richly diverse phenotypically. The indices related to branch and trunk ranked highest on CV, while those associated with leaf greatest on diversity index. The principal components of the traits, such as leaf-, branch-, and trunk-related indices, largely determined the phenotype of H. impetiginosus plants. The population Group II plants as classified by the cluster analysis had more dark color flowers, whereas Group I carried distinctive, attractive white blossoms that were valued generally for landscaping, cultivation, and breeding purposes.