Abstract:

Tree peony (Paeonia Sect. Moutan) is a traditional famous flower with a long history of cultivation in China. There are various cultivars of tree peony, which have rich variations in colors and shapes of flower. Itoh hybrid peony (P. Itoh Group) is the intersectional hybrid group crossed by tree peony group (P. Sect. Moutan) and herb peony group (P. Sect. Paeonia) of Paeonia. Multicolor is a special flower color pattern, both tree peony and Itoh hybrid peony are abundant in multicolor cultivars, but the existing floral classification cannot fully describe the floral characteristics of compound color varieties. Based on field investigation and literature analysis, this study classified the flower color of multicolor cultivars of tree peony and Itoh hybrid peony groups into 3 categories, including single plant multicolor, single flower multicolor and multicolored in florescence time, of which single flower multicolor was classified into 6 types. The results indicate that tree peony cultivars are rich in multicolor types, especially there are many multicolor cultivars in Northwest tree peony cultivar group. Itoh hybrid peony has a high proportion of multicolor cultivars, mainly of the gradient color type, and a few cultivars combine multiple types of stripes, spots, and single flower multicolor, etc. In this paper, we propose a new scheme for the classification of multicolor flower of both tree peony and Itoh hybrid peony which can be used as a reference for flower color improvement and DUS test of Paeonia.

Key words: tree peony, Itoh hybrid peony, multicolor cultivars, flower color type