| Cornus officinalis is a unique and multi-purpose forest tree specie in China,but also authentic traditional Chinese medicine,which flesh has a hypoglycemic,anti-shock,anti-bacterial anti-inflammatory effect and be used as medicine and processed foods.Dogwood is mainly produced in Anhui,Shaanxi,Henan and Zhejiang provinces,and concentrated distribution in Funiu Mountain,Tianmu Mountain area and Qinling Mountain.With the developing of dogwood,the scope and planting area is gradually increasing,but the yield and quality of the fruit is irregularity which affects the post-processing of the fruit.Therefore,on the basis of dogwood germplasm investigation,collection and evaluation,it has important significance for improving variety system and standardization of traditional forest industry to develop the research of dogwood breeding new varieties.In this paper,129 samples were collected from Henan,Zhejiang,Shaanxi,Hunan,Hebei,Anhui,Shandong,Sichuan,Chongqing,Guizhou and Shanxi and other 11provinces(municipalities)for this study,the genetic diversity of nationwide dogwood germplasm resources was analyzed by ISSR Markers.On this basis,the core collection of dogwood was constructed by contrasting the method of core collection construction,which has an important guiding significance on dogwood germplasm collection and evaluation,conservation and utilization.The main results of the paper are as follows:1.11 polymorphic and clear band primers were screened out in this study,and used for polymorphism amplification of 129 dogwood germplasm.Results showed that a total of 87 bands were identified,the number of polymorphic bands was 87 and polymorphic ratio reached 100%.Observed number of alleles,effective number of alleles,Nei's genetic diversity index and Shannon's information index were 2.000,1.4388,0.2593 and 0.4006,indicating that 129 dogwood have a very rich genetic diversity.In addition,the dogwood samples in the regions also have higher genetic diversity,among the genetic diversity of Zhejiang(Na = 1.8851,Ne = 1.5051,H =0.2920,I = 0.4388)and Anhui(Na = 1.6552,Ne = 1.4075,H = 0.2317,I = 0.3445)are highest than other provinces(municipalities);and genetic diversity of Hunan and Hebei is lowest,and genetic distance between the two provinces showed largedifferences exist at the DNA level.2.Using UPGMA method of dogwood germplasm cluster analysis,the group is divided into eight categories when genetic similarity coefficient Gx is 0.714.Wherein genetic consistency between Zhouzhi No.3 and No.4 in Shandong are maximum(0.989),indicating that the genetic relationship between the two are most recent;genetic uniformity between Zhejiang No.17 and Anhui Shexian No.1 are minimum(0.368),shows that between the two individuals there may be some geographic isolation.3.The core collection construction of dogwood was using randomized,allele preferred sampling strategy combining with SM,Jaccard and Nei&Li genetic distance.After 5 clustering times,sampling ratio and genetic diversity were compared to ensure that six groups core collection of the fourth time build were initial core collection.Genetic diversity of six groups core collection were using T-test with the original core collection respectively,showing that allele preferred sampling strategy combine Nei&Li genetic distances build core collection of 34 samples as dogwood.It includes26.36% germplasm samples of the 129 initial collection,the retention ratio of number of polymorphic loci,percentage of polymorphic loci,observed number of alleles,effective number of alleles,Nei's genetic diversity index and Shannon information index were 100.0%,100.0%,100.0%,103.5%,112.38% and 111.58% respectively.Combined with the analysis of 13 phenotypic traits,further proved that the construction of core germplasm could represent the genetic diversity of the original germplasm. |
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