The numerical classification and grading standards of daylily (Hemerocallis) flower color

This study collected 183 Hemerocallis varieties to conduct numerical classification of flower color and provide valuable baseline data and foundational theory for normalization and precision of Hemerocallis. The color CIELab phenotypes were collected via colorimeter (CR-10 Plus), which separately measured three sepal and petal parts (throat, eye and limb). The colors of experimental samples were artificially named by the Royal Horticultural Society Colour Chart (RHSCC). All the data were analyzed using R software. The results showed that the throat was predominantly green-yellow, light yellow and yellow; green-yellow accounted for the largest proportion of sepals (67.76%) and petals (69.40%). The eye was more abundant, and there were significant differences between sepals and petals. The limb was clustered into five color groups (orange, yellow, pink, red and purple); the yellow group had the most varieties for both sepals and petals, containing 57.38% and 55.74%, respectively. Both sepals and petals had significant differences (pa*) and color angle (h) for the throat, eye and limb. However, the difference in CIELab phenotypes between the eye and limb were not significant. According to “Dual Classification”, the color classification standard was proposed as a 3-level standard. The color of sepal and petal consistency served as the first standard, and the color of limb was the second standard. The color pattern types of pure, gradual change, watermark and eye spot, served as the third standard. It has been proposed that all the 183 experimental varieties were divided into two categories, five groups and finally four types. This study provides a classification basis and reference for numeric and standardized color phenotype description for Hemerocallis.

本研究收集了183个萱草（Hemerocallis）品种，开展花色数值分类研究，为萱草性状的标准化与精准化研究提供宝贵的基础数据与理论支撑。本研究通过色差仪（CR-10 Plus）采集花色的CIELab表型数据，分别测量了花萼与花瓣的三个部位：喉部（throat）、眼斑区（eye）与瓣缘（limb）。实验样本的花色由英国皇家园艺学会比色卡（Royal Horticultural Society Colour Chart, RHSCC）进行人工定名。所有数据均采用R软件开展分析。结果显示，喉部花色主要为绿黄色、浅黄色与黄色；花萼与花瓣的绿黄色占比均最高，分别达67.76%与69.40%。眼斑区花色更为丰富，且花萼与花瓣间存在显著差异。瓣缘可聚类为5个色系群：橙色、黄色、粉色、红色与紫色；其中黄色色系群的品种数量最多，花萼与花瓣占比分别为57.38%与55.74%。花萼与花瓣的喉部、眼斑区及瓣缘的CIELab表型参数中，a*值与色相角（h）均存在显著差异，但眼斑区与瓣缘的CIELab表型差异并不显著。基于“双分类法”，本研究提出三级花色分类标准：第一级以花萼与花瓣的花色一致性为依据，第二级以瓣缘花色为依据，第三级以纯色、渐变色、水印纹与眼斑4种花色模式类型为依据。研究将183个实验品种划分为2大类、5个色系群，最终归为4种花色模式类型。本研究可为萱草花色表型的数值化与标准化描述提供分类依据与参考。