Morphological And ISSR Molecular Marker Analysis Of Nine Peony Resources

Hunan peony belongs to the variety group of South China peony,and is also one of the natural distribution areas of peony.Its cultivation has a long history.Hunan native peony has unique ornamental value and excellent characteristics of high temperature and humidity tolerance.However,according to the investigation of native peony varieties resources in Hunan in recent years,it can be found that some native peony resources in Hunan have lost or died due to the lack of conservation and management of ornamental peony resources,and some new seedling variant lines with high ornamental value have also been found.These resources may be formed by natural hybridization or natural mutation.Their origin and genetic relationship are unknown.In this study,we used morphological and ISSR molecular markers to analyze the genetic relationship of five new excellent individual tree resources and four native tree resources in Hunan,which may be related to them,in order to identify the new excellent individual tree resources of Peony.The genetic relationship will accelerate the breeding process of fine peony varieties,and provide theoretical guidance for the development and utilization of native peony germplasm resources and the breeding of new varieties resistant to humidity and heat in Hunan.The main results are as follows:? Morphological analysis was carried out on 28 main traits of 9 native peony resources in Hunan Province.The quantitative classification criteria and genetic relationship of the varieties were discussed by R-type cluster analysis,Q-type cluster analysis and principal component analysis.The results of R-type cluster analysis showed that the correlation coefficients of corolla transverse diameter and corolla longitudinal diameter,number of carpels and flower height were greater than 0.9.The number of petals and pedicel length(r=0.986),shape of petals and color of stamen filament(r=0.934),number of outer petals and flower color(r=0.933),so the six characteristics of corolla longitudinal diameter,number of carpels and flower height were not considered in Q-type cluster.The results of principal component analysis showed that 9 traits,such as petal number,petal size and corolla transverse diameter,contributed more.The results of Q-type cluster analysis showed that the nine native peony resources in Hunan were divided into two categories: ‘Fengyou No.4',‘Fengdanbai',‘Fengdanfen',Paeonia ostii,‘Baoqinghong' and ‘Fengyou No.2';‘Fengyou No.1',‘Fengyou No.3' and'Fengyou No.5'.? PopGen32 software was used to analyze the genetic similarity.The results showed that the genetic distances between nine tested peony materials were 0.3383-0.7921,the genetic similarity coefficient was 0.4529-0.713,and the average genetic similarity coefficient was0.5772.Among them,Paeonia ostii and ‘Fengdanfen' have the highest genetic consistency and the closest genetic distance,which indicates that they are closely related.The genetic consistency of ‘Fengdanfen' and ‘Fengyou No.5' was the lowest and the genetic distance was the farthest,which indicated that they had a far genetic relationship.The results of genetic similarity analysis showed that there were some genetic differences among 9 tested peony varieties.? According to UPGMA tree-like clustering map,when the genetic similarity coefficient was 0.54,nine peony cultivars could be divided into two categories.The first category includes ‘Baoqinghong' and ‘Fengyou No.5'.The second category includes Paeonia ostii,‘Fengdanbai',‘Fengdanfen',‘Fengyou No.1',‘Fengyou No.2',‘Fengyou No.3' and‘Fengyou No.4'.When the genetic similarity coefficient is 0.59,the second group can be divided into two sub-groups.The first sub-group includes Paeonia ostii,‘Fengdanfen",‘Fengdanbai' and ‘Fengyou No.1',Paeonia ostii is clustered with ‘Fengdanfen' and‘Fengdanbai',while ‘Fengyou No.1' is more closely related to ‘Fengdanbai'.The second sub-group includes ‘Fengyou No.2',‘Fengdanbai'.‘Fengyou No.3' and ‘Fengyou No.4'.Among them,‘Fengyou No.2' is separately divided into one category,and its morphological characteristics are indeed unique.The results of genetic clustering analysis of ISSR molecular markers in this study are different from those of morphological genetic clustering analysis.Morphology studies mainly distinguish genetic variation and species difference from plant phenotypic traits.The differences of plant phenotypic traits are affected by both environment and genes.Not all gene expression will affect the differences of phenotypic traits.Therefore,the differences of plant genetic variation and phenotypic traits at molecular level are not necessarily fully correlated.