Comprehensive Evaluation of Phenotypic Characteristics of 101 Single-Flowered Clematis L. Germplasm Resources

To clarify the diversity and comprehensive evaluation of phenotypic trait, 101 single-flowered Clematis L. varieties were used as experimental materials. Eleven quality traits and seven quantitative traits were performed on variation and diversity analyses to provide reference data for the identification, horticultural application, and breeding objectives of single-flowered Clematis L. germplasm resources. The phenotypic trait variation and diversity analysis showed that there were different in the eleven quality traits with a variation coefficient of 14.06%～77% and a diversity index of 0.1971～1.6271. The variation coefficient of the midrib(77%) was the largest. The diversity index of the seven quantitative traits was 1.0274 to 1.4163 with rich genetic diversity, all of them were greater than 1.0. The correlation analysis results indicated that most quantitative traits had highly significant correlation. Cluster analysis divided the 101 single-flowered Clematis L. varieties into four categories by. Class Ⅰ included 62 varieties with smaller flower diameters and average comprehensive performance of floral organ traits. Class Ⅱ gathered 21 varieties with medium-sized flower diameters. Class Ⅲ had only one variety characterized by the smallest flower diameter, calyx length, sepal aspect ratio, stamens number, and stamen length. Class IV had seven varieties, mainly with larger flower types and excellent comprehensive performance of floral organs traits. These result could provide support for the classification and evolution of Clematis L. varieties from a morphological perspective, a reference for further developing with excellent flower organ ornamental traits, germplasm innovation, and variety improvement. Principal component analysis extracted three principal components with a cumulative contribution rate of 89.541%, which could represent comprehensively most of the information of single-flowered Clematis L. phenotype data. Through comprehensive evaluation and ranking of single-flowered Clematis L. phenotypic traits, the top ten varieties were 'Thyrislund' 'Leinster' 'Kizashi' 'Dorothy Tolver' 'Olympia' 'Justa' 'Doctor Ruppel' 'Omoshiro' 'Snowdrift' and 'Luiza' with excellent comprehensive performance of floral organ traits, which would lay a foundation for the breeding of single-flowered Clematis L. varieties.