Construction of a high-density genetic map of tree peony ( Paeonia suffruticosa Andr. Moutan ) using restriction site associated DNA sequencing (RADseq) approach

High-density genetic maps play a vital role in dissecting genetic components of biologically or agronomically important traits and molecular marker-assisted selection breeding, especially for a species with limited genomic information. Tree Peony ( Paeonia suffruticosa Andr. Moutan DC.) is a traditional flowering plant in China, with important ornamental value, which have been spread around the world. However, less genetic and genomic information is available for the tree peony molecular studies. Here, we performed restriction site-associated DNA sequencing (RADseq) of an F1 population, derived from a traditional variety “Qing Long Wo Mo Chi (QL)” and a variety “Mo Zi Lian (MZL)”. High-density genetic maps were developed using RADseq markers for female (1471 markers) and male (793 markers) parents. They covered 965.69 and 870.21 cM, with the average marker intervals of 0.66 and 1.10 cM along the seven and five linkage groups (LGs), respectively. Furthermore, the identified markers were assigned to 1671 bins, representing the unique genetic positions in LGs, and inter-marker distances smaller than 5 cM covered 97.93% of genetic maps. This study suggests that rapid de novo construction of genetic maps in peony could be conducted through RADseq approach, which provides an important tool for further linkage mapping and genomic structure analysis, and enable development of molecular markers for molecular breeding in tree peony.