Evaluation Of Rose Germplasms And QTL Mapping Of Ornamental Traits

Based on the investigation of the biological characteristics of rose resources,a comprehensive evaluation and analysis of rose germplasm resources were established;the flower color of 200 rose varieties was analyzed;the genetic segregation population of F1 generation was constructed,and the flower diameter,number of petals and flower color were investigated;study of genetic variation analysis and gene mapping,based on the phenotypic observation data of the F1 population,the genetic variation of main ornamental traits were analyzed by using major gene plus polygene mixed inheritance model;Use BSA-seq technology excavated molecular markers closely linked to the number of petals and flower color,and establish the screening and positioning analysis of related genes.The results will lay the foundation for the development of molecular marker breeding technology in rose.The main findings are as follows:(1)Comprehensive evaluation of 138 Rose varieties in summer and autumn in Beijing Institute of Landscape Architecture Rose resource nurseryThe analytic hierarchy process was used to establish a rating model for the viewing effect of 138 rose varieties in the summer and autumn in Beijing,and 33 rose varieties with excellent viewing effects in summer and autumn in Beijing were selected.A comprehensive evaluation of the 14 traits of each variety was established,and it was divided into four grades according to the evaluation scores and actual growth conditions in the field:grade-Ⅰ including 29 varieties,such as ’White peach sorbet’ and ’Honey Caramel’;grade-Ⅱ including 63 varieties,such as ’Dainty Bess’and ’Fee Clochette’;grade-Ⅲ including 33 varieties,such as ’Canary’ and ’Blue Eden’;and grade-Ⅳ including 13 varieties,such as ’Akane’ and ’Lovery More’.(2)Comprehensive evaluation of 357 rose germplasm resources in spring in SuZhou Huaguanyuanchuang Horticultural&Technology Co.,Ltd.Rose resource nurseryThe Analytic Hierarchy Process was used to evaluate and analyze the 13 traits of 357 rose germplasm resources in SuZhou,and a scientific and reasonable comprehensive evaluation system was established.Finally,86 excellent varieties suitable for extensive cultivation in SuZhou gardens were selected(including 17 Hybrid Tea Roses,18 Shrub Roses,7 Climber Roses,20 Floribunda Roses,and 24 Miniature Roses).(3)The numerical classification of rose flower color phenotypeIn order to accurately define the different flower color phenotype of Rose,colorimeter and ISCC-NBS color name was used to measure the various flower colors of 200 rose cultivars.The measured color of rose varieties can be classified.The color of rose cultivars were classified into seven groups,including white group,yellow-green group,royal purple group,red group,orange group,pink group,yellow group.(4)Genetic analysis of floral traits in the two F1 generation populationsTwo rose F1 genetic populations were constructed:population 1 was Rosa Chinensis ’Old Blush’×Rosa Chinensis var.spontanea;population 2 was Rosa Chinensis ’Yee Chino’×Rosa Chinensis Climber ’Old Blush’.the coefficient of genetic variation of petal number in the two populations is high by analyzing with IBM SPSS Statistics 21 and excel software,indicating that petal number has richer genetic variation.flower color phenotype was analyzed on 82 individual plants of F1 population 2,and the population was classified into three groups:dark pink group,pink group,and light pink group.(5)Analysis of the major gene plus polygene mixed inheritance modelThrough analysis of the major gene plus polygene mixed inheritance model,the two genetic models of ornamental traits in two populations,and the optimal model for the number of petals in the two candidate models was 2MG-ADI(two pairs of additive-dominant-epitope major gene control);the optimal model for flower diameter traits is 0-MG(minor effect poly-gene control);in the R.Chinensis ’Yee Chino’×Climber ’Old blush’ population,the flower color traits model is the 2MG-AED model(two pairs of complete dominant gene control);In the F1 generation population of R.Chinensis ’Old Blush’ × R.Chinensis var.spontanea,the genetic model of flower color traits is 2MG-ADI(two pairs of additive-dominant-epitope major gene control).(6)Screening of candidate genes related to ornamental traitsThe BSA-seq technique was used to construct the DNA mixed pools of flower color and petal quantity traits for sequencing,and compared with the published reference genome of R.Chinensis ’Old Blush’,the comparison efficiency of each mixed pool was above 91%.Sequencing results were analyzed by SNP and InDel,and the sites in the candidate region were annotated and screened.Finally,47 nonsynonymous mutation SNPs and 1 frameshift mutation InDel were obtained for petal traits,and 4 candidate genes related to the number of petals were located;A total of 32 non-synonymous mutant SNPs were obtained for flower color traits,and 5 candidate genes related to flower color were mapped.