Flower color classification and correlation between color space values with pigments in potted multiflora chrysanthemum

Flower color, which varies widely in potted multiflora chrysanthemum, is an extremely important character for classification. A quantitative definition of the flower color of potted multiflora chrysanthemums and the establishment of a standard color classification system may help us to evaluate the germplasm resources effectively. In this study, 273 potted multiflora chrysanthemum advanced lines were selected as materials. First, color classification results were compared between two methods: one is a combination of CIELAB and Munsell color systems, and the other one applying Q clustering analysis based on the CIELAB color system. We then divided the 273 lines into six color groups. The composition and content of anthocyanins and carotenoids in the different color advanced lines were identified by HPLC-MS. Two derivatives of cyanidin, cyanidin-3-O-(6″-O-malonyl-glucoside) and cyanidin-3-O-(3″,6″-O-dimalonyl-β-glucopyanoside), were identified in the pink, purple, orange-brown, and red lines. The carotenoids, primarily consisting of violanthin, z-violanthin, 9′z-lutein 5,6-epoxide, lutein, α-carotene, β-carotene, and 9z-β-carotene, were identified in all chrysanthemum advanced lines. Additionally, a*, represents the green-red component with green in the negative direction and red in the positive direction, was strongly positively correlated with cyanidin-3-O-(6″-O-malonyl-glucoside) (r = 0.884, P < 0.01), cyanidin-3-O-(3″, 6″-O-dimalonyl-β-glucopyanoside) (r = 0.864, P < 0.01) and total anthocyanins (r = 0.896, P < 0.01) by linear regression analysis and Pearson correlation coefficients. Meanwhile, b*, represents the blue–yellow component with blue in the negative direction and yellow in the positive direction, was strongly positively correlated with lutein (r = 0.804, P < 0.01) and total carotenoids (r = 0.881, P＜0.01) in potted multiflora chrysanthemum. Then, linear equations were obtained according to the significant correlations between a* and anthocyanins and b* and carotenoids. These results were helpful for rapidly and accurately estimating the content of anthocyanins/carotenoids.