Abstract:

This study investigated the dynamic distribution of flower color in 100 cultivars of ornamental crabapple（Malus spp.）across different developmental stages. Digital color analysis was conducted during the large bud stage and full blooming stage to explore flower color classification and reveal the variation patterns of color during flowering. The results indicated that flower color richness was highest at full bloom. Throughout the flowering stages，the color dynamics of ornamental crabapple generally shifted toward higher lightness（L^*），lower redness（a^*），lower yellowness（b^*），and lower chroma（C^*）and hue angle（h^°），indicating a progressive color fading during the flowering process. At full bloom，the 100 cultivars could be categorized into five major color groups：white（26%），pink-white（27%），pink（21%），red（10%），and purplish-red（16%）. Distinct phenotypic differences among these groups suggest that L^*，a^*，and b^* values can serve as effective criteria for flower color classification in ornamental crabapple. Furthermore，based on L^* and C^* values，these five color groups were divided into two broader clusters：ClusterⅠ（white，pink-white，and pink）and ClusterⅡ（purplish-red and red）. The ornamental evaluation criteria proposed in this study indicate that for white-flowered cultivars，higher L^* and lower C^* values correspond to better ornamental performance，whereas for other color groups，superior ornamental value is associated with both high L^* and high C^* values. Based on these criteria and using the golden-section method in a two-dimensional L^*-C^* distribution plot，19 cultivars with outstanding floral display and high ornamental value were identified.

Key words: ornamental crabapple, flower color parameter, quantitative classification