Multi-level correlation analysis of flower color and fragrance in wild tree peony (Paeonia suffruticosa)

Tree peony (Paeonia suffruticosa Andr.), renowned for its large, colorful, and fragrant flowers. Although flower color and fragrance together determine the ornamental and economic value of tree peony, the coordinated regulatory properties between them are still poorly understood, which represents an important knowledge gap for both breeding efforts for specific color and fragrance combinations and industrial production. In this study, a multilevel correlation analysis between pigment and volatile was conducted across nine wild tree peony, including phenotype-sensory level, phenotype-volatile organic compound (VOCs) level and pigment-VOCs level. Phenotypically, yellowness (b*) and chroma (C) positively correlated with floral type and benzenoid alcohols while redness (a*) associated with aldehydes. Furthermore, anthocyanins are closely related to ketones, while carotenoids are significantly associated with benzenes and terpenes. Therefore, there was indeed a potential correlation between flower pigments and VOCs in wild tree peony species. Taken together, the results inform synergistic breeding strategies for optimizing both flower color and fragrance in tree peony and provide a valuable theoretical basis for the rapid screening of germplasm resources of materials with both aroma and color. Also for specific flower color-flavor combinations it is possible to further screen for specific pollinators in the future, resulting in pollinator syndromes.