| Triadica sebifera is a deciduous tree of the genus Sapium in the family Euphorbiaceae.The autumn leaves of T.sebifera are rich in color types,which can be roughly divided into the following five color systems:green,purple,red,orange and yellow,with high ornamental value and garden planting.In this research,15 phenotypic traits and 6 phenological characters of T.sebifera were used as indicators for measuring,progressed comprehensive evaluation of the phenotypic diversity of ornamental T.sebifera by correlation analysis,principal component analysis,cluster analysis and stepwise linear regression analysis,We also used SSR primers to PCR amplify 21 T.sebifera,construct fingerprint profiles,conduct T.sebifera identification and explore the genetic diversity of T.sebifera,and showed the following research results.(1)Fifteen phenotypic traits of T.sebifera were determined,the 15 phenotypic traits include seven qualitative and eight quantitative traits,and all with varying degrees of variation.In qualitative traits,tip shape had the highest diversity index and rich types,with 6 categories,the diversity index up to 1.46.and the lowest diversity index was 0.65 for the position of the widest leaf.In quantitative traits,petiole length had the highest diversity index;and the lowest was leaf area;the coefficient of variation of leaf area was the largest at 35.42%,and the variety with the largest leaf area was ’Huihuang’ at 4213.16mm2 and the variety with the smallest was ’Canlan’ at 1479.17mm2.(2)Six phenological characteristics of T.sebifera were determined,revealed significant differences in the length of the phenological period among the species,with a relative concentration of days in the leaf development and ornamental periods.Most varieties started to sprout in early March,and the leaf-bud period was 18～40days,the shortest variety was ’Xuanliheshan’ and the longest variety was’Haibinzijing’;Most varieties were slow to develop leaves,and the leaf-spreading period was 8～27days,The shortest variety is ’Zhengyan’ and ’Haibinzijing’,the longest variety is ’Zilinglong’.Discoloration period lasted for 7～12days,which is relatively concentrated;the ornamental prosperous period is 6～27days,the difference between the shortest variety ’Feiyunzhaoshui’ and the longest variety ’Zilinglong’ is 21days;the ornamental period is 18～37days,the difference between the shortest variety’Feiyunzhaoshui’ and the longest variety ’Zilinglong’ is 19days;the leaf drop period is 6～18days,the longest variety is ’Pudazi’.(3)Phenotypic clustering at genetic distance 7 classified the 21 ornamental T.sebifera into 3 major groups.Autumn leaf surface colour,leaf shape,leaf base form,leaf area and ornamental period were the main factors in making the distinction between different ornamental T sebifera.The comprehensive phenotypic evaluation finally selected 13 elements,including leaf length,leaf width,petiole length,petiole width,leaf area,leaf base angle,leaf perimeter,leaf shape,leaf base form,autumn leaf surface colour,leaf bud stage,leaf spreading stage and ornamental stage,which can be used as important indicators for the evaluation of ornamental T.sebifera.(4)Sixteen primer pairs with clear bands and good polymorphism were selected from 39 primer pairs,and the selected 16 primer pairs were used to amplify a total of 181 bands for 21 ornamental T.sebifera.Three SSR primer pairs were used to establish 21 T.sebifera DNA fingerprints for the identification of T.sebifera.(5)The similarity coefficient was calculated and cluster analysis was performed on the SSR data of 21 T.sebifera.The Dice similarity coefficient of T.sebifera ranged from 0.14 to 0.54,and the average similarity coefficient was 0.34.When the Dice similarity coefficient was 0.22,the 21 ornamental T.sebifera could be divided into four categories.In conclusion,the combination of SSR marker technology and phenotypic traits can be used for identification and genetic diversity analysis of T.sebifera,which can provide reference for identification and selection of improved T.sebifera. |
