Evaluation of Genetic Diversity and Identification of Cultivars in Spray-Type Chrysanthemum Based on SSR Markers

Background/Objectives: Chrysanthemum (Chrysanthemum morifolium), a key ornamental and medicinal plant, presents challenges in cultivar identification due to high phenotypic similarity and environmental influences. This study assessed the genetic diversity and discrimination of 126 spray-type chrysanthemum cultivars. Methods: About twenty-three simple sequence repeat (SSR) markers were screened for the discrimination of 126 cultivars, among which six SSR markers showed polymorphic fragments. Results: Results showed high polymorphism across six markers, with an average of 3.8 alleles per locus and a mean polymorphism information content (PIC) of 0.52, indicating strong discriminatory efficiency. The average observed heterozygosity (Ho) was 0.72, reflecting significant genetic diversity within the cultivars. Cluster analysis using the unweighted pair group method with arithmetic mean (UPGMA) grouped the cultivars into seven clusters, correlating well with the PCA. Bayesian population structure analysis suggested two primary genetic subpopulations. Conclusions: These findings confirm SSR markers as an effective tool for the genetic characterization and precise discrimination of spray type chrysanthemum cultivars, offering significant applications in breeding, cultivar registration, and germplasm conservation. The SSR marker-based approach thus provides a reliable and efficient strategy to enhance the management and commercialization of diverse chrysanthemum germplasm collections.