The chloroplast genome of the allotriploid, <i>Paeonia × lemoinei</i> cv. Oukan, and its phylogenetic implications

The chloroplast genome of <i>Paeonia</i> × <i>lemoinei</i> cv. Oukan, a newly identified allotriploid from <i>Paeonia</i> sect. <i>Moutan</i>, shows typical tree peony features in size, structure, and gene content. A maximum-likelihood phylogenetic analysis revealed cv. Oukan and the known triploid cv. Shouanhong clustered into subsect. <i>Delavayanae</i> and subsect. <i>Vaginatae</i>, respectively. Cv. Oukan is closely related to its maternal parent cv. High Noon, while autotriploid cv. Shouanhong is sister to <i>P. ostii</i> but genetically distinct. This study provides genomic resources and phylogenetic insights for the first allotriploid tree peony, suggesting lineages in both subsects could serve as maternal parents for breeding triploid cultivars.