Genetic Diversity And Phylogeny Of Rosa Section Chinenses Germplasm Resources

Rosa sect.Chinenses is an important ornamental plant group of genus Rosa: Rosaceae.It is one of the most important parents in the breeding of Modern Roses.It is also an important material for research of continuous flowering,double flower,petal colour,fragrance and other ornamental traits.There are abundant germplasm resources in China.Some resources have transitional characters between different species.However,the in-depth study of these germplasm resources has not been carried out.In order to explore the genetic diversity of rose germplasm resources and clarify the genetic background of rose germplasm resources,32 Chinenses germplasm resources were collected in this study.Morphological traits,SSR molecular markers,chloroplast DNA markers and single copy nuclear gene markers were used to collect the genetic diversity information.ANOVA analysis,cluster analysis,STRUCTURE analysis and phylogenetic analysis were used for discussing the differences of morphological traits,genetic structure and background of these resources.The results are as follows:1.The morphological characters of Chinenses are similar.The inheritance of hip size and flower diameter vary among different species.These characters could be used as an auxiliary of morphological taxonomy.2.SSR markers in Chinenses have high genetic diversity.Polymorphic information(PIC)is between 0.576 and 0.873.AMOVA analysis shows that genetic variation mainly comes from individuals,accounting for 91.74%.STRUCTURE analysis shows that R.odorata,R.chinensis have different genetic backgrounds.While Chinenses complex contains the genetic background of both primitive taxa.3.The nucleotide polymorphisms of chloroplast DNA markers in the Chinenses germplasm resources rang from 0.0017 to 0.0041.Phylogenetic analysis shows their maternal inheritance could be R.odorata var.gigantean or R.chinensis var.spontanea.R.odorata var.gigantea could be maternal parent of R.odorata.4.Three molecular markers are combined to analyze the genetic background of the rose group germplasm resources.The results support the traditional classification of R.odorata var.gigantean and R.chinensis var.spontanea,but do not support the classification of the double-flower R.odorata varieties.Chinenses complex could be divided into 3 groups,R.odorata group,R.chinensis groupand a mixed group.This study preliminary explores the relationship of native roses in China.For roses genome,ornamental traits analysis,functional gene identification and cross breeding,this study provides theoretical basis,screens materials for further research.By analyzing Chinenses genetic background and taxonomic placement,this study provides a theoretical basis for protection and utilization of rose germplasm resources,as well as retracing the breeding process of Chinese rose.