Analysis of genetic relationships in tree peony of different colors using conserved DNA-derived polymorphism markers

• The CDDP marker system and designed primers were efficient for the identification and genetic relationship analysis of tree peony genotypes.
• It is the first time that CDDP marker targeted flower color by gene-targeted primers and successfully made most tree peony accessions cluster based on flower color.
• Clustering of tree peony germplasm corresponded to origins and Zhongyuan group cultivars mainly based on flower color.

The genetic diversity and relationships among 64 tree peony (Paeonia suffruticosa) germplasm of different colors were analyzed using conserve DNA-derived polymorphism (CDDP) markers. Of 16 primers screened, 13 primers could produce unambiguous and reproducible bands. Using 13 designed CDDP primers, 152 bands were generated with an average of 11.69 bands per primer among 64 accessions, with 149 (98.03%) being polymorphic. Further, accession-specific markers were observed in eight accessions. There was a significant positive correlation between the resolving power (Rp) of each primer and the number of accessions identified (r = 0.96, **P < 0.01). 64 accessions were clustered by UPGMA into 5 major groups at a similarity index value of 0.69 based on the CDDP marker data. Clustering of tree peony germplasm corresponded to origins and Zhongyuan group cultivars mainly based on flower color. The results demonstrated that the CDDP marker system and designed primers were efficient for the identification and genetic relationship analysis of tree peony genotypes. It is the first time that CDDP marker targeted flower color by gene-targeted primers and successfully made tree peony accessions cluster based on flower color. The results provide useful information for the utilization of gene-targeted molecular markers on cultivar identification and genetic relationship analysis in plants.