No abstract

Flower color is an important trait of tree peony (Paeonia suffruticosa), an economically important species. The accurate classification of flower color and understanding of the mechanism involved in creating variations in flower color provide the basis of tree peony breeding and genetic research. This study used the International Commission of Illumination Color System, known as CIELAB or CIE L*a*b*, to measure the flower color of 150 cultivars of the Zhongyuan cultivar group of tree peony. Hierarchical cluster analysis and visual observations were used to divide this cultivar group into five major color lines: white, pink, red, purple, and fuchsia. The brightness (L*) of the flower color gradually decreased with an increase in anthocyanin content. The redness (a*) of the flower color was significantly negatively correlated with total anthocyanin (TA) content in the fuchsia line but was positively correlated with TA in the remaining four color lines. Six types of anthocyanins, including Cy3G, Cy3G5G, Pn3G, Pn3G5G, Pg3G, and Pg3G5G, were mainly found in the Zhongyuan cultivar group by liquid chromatography except in the white line. Stepwise regression analysis showed that Pg3G5G had a significant positive correlation with redness of flower color. Cy3G5G and Pn3G5G had a significant positive correlation with redness in pink, red, and purple color lines. However, Pn3G was negatively correlated with redness in the fuchsia line. This study lays the foundation for further development of new breeds and flower colors in tree peony and for genetic research related to flower color.