Skip to main content
ARS Home » Northeast Area » Washington, D.C. » National Arboretum » Floral and Nursery Plants Research » Research » Publications at this Location » Publication #431868
Research Project: Manage, Expand, and Evaluate the U.S. National Collection of Temperate-adapted Woody Landscape Plant Germplasm and Associated Descriptive Data

Location: Floral and Nursery Plants Research

Title: Ploidy and genome-size variation in Loropetalum chinense accessions cultivated in the US

Author
item CHIA-HUNG, SHIH - North Carolina State University
item FALCONI VILLALOBOS, JOSE - North Carolina State University
item ZHANG, DONGLIN - University Of Georgia
item Rounsaville, Todd
item Dieterich Mabin, Molly
item WEATHINGTON, MARK - North Carolina State University
item CHEN, HSUAN - North Carolina State University

Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/2/2026
Publication Date: 3/16/2026
Citation: Chia-Hung, S., Falconi Villalobos, J.M., Zhang, D., Rounsaville, T.J., Dieterich Mabin, M.E., Weathington, M., Chen, H. 2026. Ploidy and genome-size variation in Loropetalum chinense accessions cultivated in the US. Genetic Resources and Crop Evolution. 73. Article 140. https://doi.org/10.1007/s10722-026-02763-2.
DOI: https://doi.org/10.1007/s10722-026-02763-2

Interpretive Summary: Loropetalum are an economically important group of ornamental shrubs, and are widely planted in the U.S. for their colorful foliage and attractive flowers. Although some plant breeding has occurred for Loropetalum, there is a limited genetic resource base of plants that have been introduced to U.S. cultivation. Characterization of genotype and phenotype would be useful to Loropetalum breeders, genebanks, and the nursery industry to support the maintenance and development of new, landscape adapted ornamental cultivars. This study investigated 54 Loropetalum accessions including those maintained in the USDA Woody Landscape Plant Germplasm Repository, characterizing relative genome size, chromosome number, and leaf morphology. The study found all accessions to be diploid except for one triploid cultivar which had arisen spontaneously in cultivation. Leaf stomata size was significantly larger in the triploid genotype. These data represent the first genome size and ploidy survey for Loropetalum, and are informative for understanding crossability among genotypes, supporting plant breeder decision making.

Technical Abstract: Loropetalum chinense and L. chinense var. rubrum (2n = 2x = 24) are popular ornamental shrubs known for their distinctive flowers and foliage color. Due to its wide adaptability, Loropetalum has been widely used in the U.S. nursery market for various landscaping purposes. Given its popularity and economic value, the limited understanding of genetic diversity among accessions presents challenges for breeding efforts. Knowledge of genome size and ploidy levels could play a crucial role in hybridization success for improving ornamental traits such as flower size, color, and plant vigor. This study investigated the relative genome sizes and ploidy levels of a wide range of Loropetalum accessions in the U.S. to contribute to future breeding strategies. Flow cytometry was used to determine genome size and estimated ploidy, and chromosome counts were performed to validate ploidy estimates of 54 Loropetalum accessions from the U.S. National Arboretum, universities, and industry. As a result, 53 were identified as diploids, and 1 as a triploid. The 1Cx genome size ranged from 2.43 to 3.21 pg, with an average of 2.72 pg. The stomata size of the triploid cultivar ‘Kurenai Daiou’ Jazz Hands Bold was significantly larger, and the stomatal density was significantly lower than the three tested diploid cultivars ‘Hakuou’ Jazz Hands White, ‘Kurenai’ Jazz Hands Pink, and ‘Beni Hime’ Jazz Hands Mini. These results provide a foundational understanding of ploidy and genome size variation in L. chinense germplasm, which will benefit future Loropetalum breeding efforts.