Variation Analysis Of Leaf Phenotypic Characteristics From Different Provenances And Ornamental Value Assessment Of Liquidambar Formosana

In order to reveal the difference and variation of leaf phenotypic traits of different garden tree species of Liquidambar formosana,and provide support for germplasm resources and breeding of superior varieties.In this study,24 provenances and 493 families of L.formosana were selected,using the methods of variance analysis,coefficient of variation analysis,correlation analysis,principal component analysis,cluster analysis and multiple comparison,Nine leaf shape phenotypic traits（leaf length,leaf width,middle lobe length,middle lobe width,Angle between middle lobe and adjacent lobe,ratio of middle lobe to leaf length,ratio of leaf length to width and petiole length）and four leaf color parameters（L*,a*,b*and C*）were studied and analyzed;Analytic Hierarchy Process（AHP）was used to evaluate the ornamental properties of different garden tree species of L.formosana,with the aim of screening out those that are of high ornamental value in Guangdong and providing a scientific basis for L.formosana breeding and landscape cultivation of color leaf trees,The results showed:（1）There were highly differences among and within provenances of L.formosana leaves from different provenances（P<0.01）,and the variation among provenances（13.10%）was greater than that within provenances（12.03%）.The percentage of variance component of13 leaf surface traits among provenances was higher than that within provenances;the mean percentage of variance component among provenances was 11.09%,which was significantly higher than that within provenances（2.49%）.The results indicated that the variation of provenances phenotypic traits of L.formosana was mainly from among provenances.（2）According to the correlation analysis of phenotypic traits,there were 66 pairs of highly significant correlation among traits,including 34 pairs of highly positive significant correlation,32 pairs of highly negative significant correlation,5 pairs of significant correlation,3 pairs of positive significant correlation and 2 pairs of negative significant correlation.The correlation between phenotypic traits and environmental factors indicated,L*in leaf color parameters was significantly positively correlated with altitude and C*had a significant positive correlation with latitude.In leaf shape traits,the ratio of crack length was significantly negatively correlated with longitude and positively correlated with altitude;The aspect ratio was significantly negatively correlated with altitude.（3）The contribution rates of the 1st to 5th principal components of phenotypic character variation of L.formosana provenances were 31.915%,20.923%,15.823%,9.869%and8.185%respectively.The leading components in the 1st to 5th principal components were leaf size,leaf color saturation and brightness,leaf crack degree,leaf morphology and leaf red and green range.Cluster analysis was carried out on the leaf shape and leaf color parameters of 24 L.formosana provenances.When the Euclidean distance was 10,the leaf shapes of 24 provenances（Leaf-shaped clustering of provenances）could be clustered into4 categories;When the Euclidean distance was 7.5,the leaf colors of 24 provenances could be grouped into four categories;and the clustering results of leaf phenotypic traits had no obvious correlation with geographical distribution.（4）The analytic hierarchy process（AHP）was used to construct comprehensive evaluation system of ornamental value of garden tree species of L.formosana,According to the classification index of DUS L.formosana,combined with the role of L.formosana in garden plant landscaping and the actual investigation,four aspects of leaf color,leaf shape,tree shape and resource potential were determined as the core of the evaluation system,and14 closely related evaluation indexes were screened out.The weight value of the criterion layer was Y₁（leaf color）>Y₂（leaf shape）>Y₃（tree shape）>Y₄（resource potential）,in which the maximum weight of ornamental characters of leaf color was 0.5547.The total weight of factor layer was as follows:L₄（autumn leaf color）>L₃（spring leaf color）>L₇（middle lobe shape）>L₂（leaf brightness）>L₉（plant branch posture）>L₆（leaf size）>L₁₄（growth adaptability）>L₁（leaf saturation）>L₈（leaf base shape）>L₁₀（plant height）>L₁₃（stress resistance）>L₁₁（crown shape）>L₅（petiole length）>L₁₂（DBH）.The three factors of leaf color ranked the top four,indicating that leaf color was the most important ornamental part of L.formosana.In the total ranking of factors,petiole length and DBH ranked the last,which had little impact on the evaluation of the value of ornamental characters of L.formosana.（5）The 24 provenances of L.formosana were divided into 4 grades by analytic hierarchy process（AHP）.It was found that six provenances in Nanjing,Jiangsu（NJ）,Zhoushan,Zhejiang（ZS）,Huangshan,Anhui（HS）,Yunnan Funing（FN）,Wengyuan,Guangdong（WY）and Baise,Guangxi（TL）had the highest ornamental value,belonged to the second first level,which could be used as the key provenances of L.formosana for landscaping promotion in Guangdong Province,and other grades could also be reasonably promoted and developed according to their own characteristics.