Genetic Diversity Of Ancient Tea Trees In Sandu County,Guizhou Province

Ancient tea tree(Camellia sinensis)refers to wild tea trees that grow in natural forests and are over 100 years old.They also include semi-domesticated artificially cultivated wild tea trees and tea trees in ancient tea gardens that have been cultivated for more than 100 years.Guizhou is one of the origins of tea trees.Sandu Shui Autonomous County is rich in ancient tea tree resources.After a long time of continuous evolution,the ancient tea tree has retained rich genetic diversity,providing valuable resources for the breeding of ancient tea tree varieties,the effective use and protection of germplasm resources.In this study,145 test materials from 5 ancient tea tree populations in Sandu Shui Autonomous County were used as samples,and ISSR molecular marker technology was used in combination with morphological features to explore the genetic diversity of ancient tea trees.Provide a theoretical basis for the protection and further research of ancient tea tree resources.The results are as follows:1.Diversity of phenotypic characteristics of ancient tea trees in Sandu County,GuizhouIn order to study the genetic diversity of ancient tea tree resources,the diversity index and coefficient of variation of the phenotypic characteristics of the tested ancient tea tree materials were analyzed.The lowest coefficient of variation of leaf quality in quality traits was 18.58%,and the highest coefficient of variation of leaf tooth depth was 50.64%;the diversity index was above 0.75 except for leaf quality of 0.55.In the quantitative traits,the lowest coefficient of variation of leaf vein logarithm was 17.76%,and the highest coefficient of variation of tree height was 60.37%;the diversity index reached more than 1.5,indicating that the tested ancient tea samples had high diversity.At the same time,the phenotypic diversity of ancient tea trees in 5 distribution areas was analyzed.The average coefficient of variation of ancient tea phenotypes in each distribution area was between 23.92 and 27.39,and the average diversity index was between 1.37 and 1.87,indicating that each distribution area The phenotypic characteristics of ancient tea trees have little difference.In order to further understand the genetic diversity of ancient tea trees,a cluster map was constructed to clearly divide the test materials into 4 categories.2.Screening of ISSR Molecular Markers for Germplasm Resources of Ancient Tea Trees in Sandu County15 ISSR primers with good polymorphism and reproducibility were selected from 100 ISSR primers.A total of 116 bands were amplified by 15 primer pairs on 145 tested ancient tea tree materials,of which 110 were polymorphic bands,the average polymorphic band ratio was 94.37%,and the polymorphism information index(PIC)wasBetween 0.68~0.86.The software POPGENEN was used to calculate the genetic agreement between 145 ancient tea tree materials between 0.4483 and 0.9655.The genetic agreement between trees is between 0.5431 and 0.9655,the genetic agreement between shrubs is between 0.7069 and 0.9569,and the genetic agreement between trees and shrubs is between 0.4483 and 0.7845.The average observed allele number(Na)was 1.9457,the average effective allele number(Ne)was 1.5293,the average Nei's genetic diversity index(H)was 0.3126,and the average Shannon information diversity index(I)was 0.4712.The 145 tested ancient tea tree materials came from 5 populations.The genetic identity of the five ancient tea populations is between 0.7498~0.9334,and the genetic distance is between 0.0689~0.2880.The average allele(Na)is 1.5453,the average effective allele number(Ne)is 1.2418,the average Nei gene diversity(H)is 0.1501,the average Shannon information index(I)is 0.2342,and the average number of polymorphic loci is 64.The average percentage of polymorphic loci was 54.53%.3.Cluster analysis of ancient tea germplasm resourcesThe software NTSYS-pc 2.1 was used to construct the UPGMA dendrogram.When the genetic similarity coefficient was 0.72,145 ancient tea tree materials weredivided into 4 categories,and the ancient tea trees in the two shrub distribution areaswere grouped into a large category.Other arbor ancient tea tree distribution areas are grouped separately.In summary: the ancient tea tree population in Sandu Shui Autonomous County of Guizhou Province has certain genetic stability and aggregation,and there is rich genetic diversity among individuals.