Evaluation Of Phenotypic Traits And Genetic Diversity Of 39 Cymbidium Ensifolium

Orchid is a precious ornamental plant with many varieties.As one of the main origins,there are thousands of original species in China.In order to understand the genetic relationship of germplasm among Cymbidium ensifolium,improve the efficiency of resource utilization and provide basis for identiflcation of varieties and cross breeding of C.ensifolium,this article carries out variety screening and genetic analysis of C.ensifolium basing on IS SR markers and main phenotypic traits.In this paper,39 species of C.ensifolium are selected as research materials,and phenotypic trait analysis,correlation analysis,principal component analysis,cluster analysis and ISSR molecular marker genetic diversity are studied from 25 morphological characteristics.The main results are as follows:1.The results of phenotypic traits analysis show that the variation range of each phenotypic trait of experimental C.ensifolium is 9.28%-76.17%,and there is a large degree of variation among each phenotypic trait.2.Correlation analysis results show that plant height is significantly related to leaf length,leaf art,and scape height;leaf number is significantly related to leaf color;leaf art and scape height are significantly related;scape flowering number is significantly related to pedicel thickness;sepal length is significantly related to flower length,flower width,sepal and petal posture,number of petal colors,lip length,and lip width;flower length is related to sepal,petal posture,and number of petal colors;flower width and lip width are significantly related;sepals and petal postures are significantly related to the number of petal colors;the number of petal colors is significantly related to the lips;the main flower color is significantly related to the lips3.The clustering analysis of phenotypic traits show that the euclidean distance of 30 C.ensifolium experimental materials ranges from 3.612 to 38.796 therein,Huicui Fenhe and Emei Narcissus has the smallest euclidean distance of 3.612,indicating the closest genetic relationship;Sujunhe and Fushan Qidie has the largest euclidean distance of 38.796,indicating that the two cultivars has the least genetic relationship.The hierarchical clustering method is used to draw the dendrogram of the phenotypic traits of 30 test materials.At the Euclidean distanceof 16,the 30 C.ensifolium test varieties are divided into 4 clusters4.The principal component analysis results show that the largest contribution value includes the scape height,flower length,and lip length which are all related to the quality of the flower.The comprehensive score of the flower traits shows that the comprehensive characteristics of Hongjunhe from Foshan,Guangdong are the best and the ornamental value is the highest,and the Shuijing Huangmei from Foshan,Guangdong has the lowest comprehensive characteristics.Among the leaf traits,the largest contributions are the number of leaves,the length and the width of leaves,and the shape of the tip of the leaves These traits are closely related to the shape of the leaves.The comprehensive scores of leaf traits show that the best comprehensive characteristics of the leaf is Tiegu Sumei from Chaoshan,Guangdong,and the lowest comprehensive characteristics of the Minshan Xianzi from Sichuan5.From 36 ISSR primers,6 primers with clear amplified bands,high reproducibility and good polymorphism are screened out.Using these 6 primers,39 C.ensifolium materials are amplified by PCR,and 64 bands are amplified,of which 57 are polymorphic bands.The average number of bands detected per primer is 11 and polymorphic bands is 10,the polymorphic ratio is 89.88%.The genetic similarity coefficient of ISSR markers ranges from 0.500 to 0.953,indicating that 39 experimental materials have rich genetic diversity.Among them,both genetic similarity coefficient between Lishan Shiwang from Hualian,Taiwan,and Qiuxue from Jieyang,Guangdong reach 0.953,indicating that the genetic material between them is largely similar to the great extend;followed by Shuijing Huangmei from Foshan,Guangdong,and Tiegu Sumei from Chaoshan,Guangdong,whose genetic similarity coefficient is 0.875,indicating their close relationship.The genetic similarity coefficients of Huangguangdeng from Zigong,Sichuan,Jinqi from Taizhong,Hongyue from Zhangzhou,Fujian,Zhonghua Caixia from Emeishan,Sichuan and Shizhanghong in Keelung,Taiwan are the lowest,all of which are 0.500,indicating that the genetic difference between them is the largest and the genetic relationship between them is the farthest.The ISSR molecular markers of 39 test materials are drawn using a hierarchical clustering method.When the genetic similarity coefficient is about 0.72,the 39 C.ensifolium test varieties are divided into 4 clusters.6.Phenotype and ISSR diversity analysis show that the genetic diversity among 39 C.ensifolium germplasm resources is relatively rich,which provides a theoretical basis for further breeding work.