Genetic Diversity Of Different Populations Of Ardisia Crenata In Fujian Province

Ardisia crenata,the genus Ardisia of Myrsinaceae,is distributed in all regions south of the Yangtze river basin in China,with umbrella-shaped plants,green leaves and red fruits,and large fruit density,which have high ornamental value.The plant contains triterpenoid saponins and coumarins,which have good medicinal value.Long-term artificial cultivation has resulted in the degeneration of ardisia crenata species and greatly restricted the development of industry.In order to solve the bottleneck in production and to fully exploit and utilize the wild resources of ardisia crenata,this paper investigates and collects them in Fujian Province.Phenotypic markers and fluorescent ISSR molecular markers were used to analyze the genetic diversity of wild resources of ardisia crenata in 20 populations in the region.It laid a foundation for the construction of genetic diversity evaluation system of ardisia crenata germplasm resources,excavation of high quality germplasm resources,development of new varieties with high ornamental value,establishment of high quality germplasm preservation system and comprehensive utilization and development system.The research results are as follows:（1）The wild germplasm resources of Ardisia crenata in Fujian Province were investigated on the spot.In the survey,it was found that the wild populations were mainly distributed in the west and north of Fujian Province.They grew in wet and shady areas with an average annual temperature of 15-22℃,annual precipitation of1400-2000 mm,elevation of 125-710 m in roadside or stream shrubs,under trees or bamboo forests and at forest margins,on shady slopes on the back of roads,etc.Its associated plants often include Callicarpa bodinieri、Cunninghamia lanceolata、Lantana camara、Ligustrum lucidum、Loropetalum chinense、Camellia japonica、Alpinia japonica、Ardisia punctata、Maesa japonica、Cyclosorus interruptus and so on.（2）The morphological characters of the wild Ardisia crenata population were abundant in variation,and the average coefficient of variation of the 15 phenotypic quantitative characters was 24.44%,among which the plant shape index had the highest coefficient of variation.The average diversity index of the 24 phenotypes was1.22,and the stem had the highest diversity index.There are abundant phenotypic diversity in Ardisia crenata.In the principal component analysis of 24 phenotypic traits of Ardisia crenata population,the characteristic values of 8 principal factors were greater than"1",and their cumulative contribution rate reached 68.50%,which could represent most information of the phenotypic traits of Ardisia crenata.Based on UPGMA clustering of 24 phenotypic traits of Ardisia crenata,it was divided into two groups.The populations of Shanghang（YH）,Fuding（CX）,Xiamen（MX）,Fuzhou（FZ）and Fuan（FA）were divided into the first group.Other populations are subdivided into the second group.The main characters of the first group were:small overall plant shape,small leaf size,single leaf shape and small fruit density.The main characters of the second group were:larger overall plant shape,larger leaf size,richer leaf shape and larger fruit density.（3）Single factor test method was adopted to select the most suitable reagent for ISSR-PCR amplification from four different types of PCR mix premix.It was found that T5 had the best PCR amplification effect on Ardisia crenata and could be used as the best PCR mix amplification reagent.The most suitable ISSR-PCR reaction system of ardisia crenata was optimized and established by orthogonal test.The system was as follows:in the 20μl system,2μl DNA template(25 ng·μl_-1),1μl primer(10μmol·L^-1),12μl PCR mix,supplemented with sterilized ddH₂O.The optimum annealing temperature for amplified primers was selected according to the gradient of annealing temperature Tm（+5℃）.Finally,after fluorescence ISSR-PCR,5 ISSR primers were amplified into 186 bands,among which 96 were polymorphic bands,and the average percentage of polymorphic bands was 55.77%.（4）According to the genetic diversity analysis by fluorescence ISSR-PCR,the percentage of polymorphic loci（PPL）of the population was 37.65%to 80.39%,Shannon index was between 0.2000 and 0.3672,the number of alleles（Na）was between 1.3765 and 1.8039,the number of effective alleles（Ne）was between 1.1923and 1.4079,and the diversity of Ne’s gene（H）was between 0.1256 and 0.2425.And the results showed that Ardisia crenata has higher genetic diversity,and the genetic diversity of the population of Jiangle（TJ）is the richest,while that of Xiamen（MX）is the lowest.Inter-population genetic variation（Dst）was 0.0592,less than intra-population genetic variation（Hs）,and intra-population genetic variation was much higher than inter-population genetic variation.The gene flow between populations is 1.4335（>1）,which has a high gene flow.And the genes between the populations permeated each other,which reduced the genetic differentiation between the populations.（5）The genetic identity of different populations was within the range of0.6201-0.9782,and the genetic distance was between 0.0242-0.559,indicating the close relationship between populations.By comparing the correlation between population genetic distance and geographical distance mantel,it was found that there was no significant correlation between geographic distance and genetic distance.UPGMA clustering and principal coordinate analysis were used to study the sample of Ardisia crenata,and it was found that there was no obvious correlation between geographical distribution and the relationship between the populations.However,there was a close gene flow among populations,and there was a certain degree of genetic differentiation among populations.According to the analysis of genetic structure,the two types of population groups were consistent with the results of sample clustering and principal coordinates,and the genetic penetration between populations was higher.