Abstract:

To investigate the flower color phenotypic diversity of natural Tulipa iliensis populations, flower color phenotypic values were measured using a colorimeter for 315 individuals from 23 natural populations. One-way ANOVA, cluster analysis and correlation analysis were used to examine flower color phenotypic diversity across populations. Results showed that the values of lightness (L^*), redness (a^*), yellowness (b^*), chroma (C^*) and hue angle (h) varied to different extents among populations, with considerable differences observed between some populations. Across the 23 populations, L^* ranged from 45.64 to 67.19, mainly indicating medium lightness; a^* ranged from 2.43 to 14.95, biased towards red with low redness intensity; b^* ranged from 19.13 to 40.83, biased towards yellow with low-to-medium yellowness intensity; C^* ranged from 25.88 to 43.50, belonging to the medium-to-high saturation level; and h ranged from 24.82 to 78.27, corresponding to red, orange-red, and orange-yellow color types. Cluster analysis indicated that at a Euclidean average distance of 5, the 23 populations could be divided into three groups. Groups Ⅰ and Ⅱ each contained 10 populations(43.48% each), with the flower color of Group Ⅱ predominantly orange. Group Ⅲ comprised three populations (BDW, BSF and NLT), accounting for 13.04%, exhibiting substantial flower color variation and dominated by orange-red. Correlation analysis between flower color traits and geographic factors revealed that L^*, b^*, C^* and h were highly significantly positively correlated with latitude, whereas no significant correlations were found between L^*, a^*, b^*, C^*, h and either altitude or longitude. This study confirmed that under the influence of latitude, flower color phenotypes of natural T. iliensis populations within the sampling area are diverse, exhibiting rich variation.

Key words: Tulipa iliensis, population, flower color, phenotypic diversity, cluster analysis