The Study On Karyotype And2n Pollen Of Rosa L.

Rosa L. belongs to Rosaceae, there are212species totally in the world and95species inChina, also known as the most famous of ornamental plants, used widely in landscaping. However,due to the impact of climatic conditions in Northeast China, there are not rose varieties of bothornamental and resistant. Wild Rose L. resources have good resistance, but their ornamentalcharacteristics are poor,and the germination rate of haploid pollen is very low, there is a bigproblem about hybridization of wild Rose L. resources and modern roses. Therefore, how toovercome the incompatibility of distant hybridization and sterility is the key of breeding.In this study, there are12wild rose species and10modern rose cultivars as test materials, thesix unknown ploidy wild rose species are the test materials of karyotype analysis, the seven wildrose species of large amount of pollen that those karyotype K (2n)=2x are the test materials of thestudy2n pollen. In hybridization,the species of higher rate of2n pollen are as male parent and10modern rose varieties are as female parent. On the one hand, this study will understand thebackground of Rose L.; Another hand, the success of distant hybridization can overcome theincompatibility and sterility, to accelerate the breeding process. The main results are as follows:1. In this study, the chromosome morphology and karyotype showed that in addition to R.rugosa Alba. is identified initially diploid, the karyotype of other species (R. rugosa f. plena, R.rugosa f. plena(Reg.)Bvhouw., R. davurica Pall.) is K (2n)=2x=14m, belongs to1A; thekaryotype of R.marretii is K（2n）=2x=12m+2sm，belongs to1B; the karyotype of R. koreana Kom.is K（2n）=2x=14m, belongs to1B. Thus, karyotype analysis methods can be identified as achromosome ploidy is a effective way. According to preliminary karyotype analysis can determinethe R.marretii and R.koreana Kom. has a closer relationship.2. Amount for shedding the pollen of7species germplasm scanning electron microscopyshowed that the wild rose germplasm was long pollen shape mainly spherical and prolate, bothwith three germinal furrow; pollen spore size is moderate powder, the average length of the polaraxis39.36μm, the average length of the equatorial axis20.84μm. Differences according to externalornamentation clustering analysis, the similarity coefficient of0.26, it can be divided into fourgroups. Group1includes R. xanthina var. normalis; Group2includes R. sertata×rugosa, R.davurica Pall.; Group3includes R.multiflora var., R. multiflora Thunb.; Group4includesR.marretii, R.koreana Kom. Pollen morphology of2n pollen can provide the basis for theidentification, relationship analysis can serve to guide future breeding in the role of parentselection. 3.2n pollen derived exists under natural conditions is very low,2n pollen shape similar tonormal pollen, pollen size of about1.5times normal. Induced by colchicine, the induction of2npollen of5species(R. multiflora Thunb., R. sertata×rugosa, R. davurica Pall., R. xanthina var.normalis, R.multiflora var.) is significant differences between and higher than under naturalconditions.The induction of2n pollen of R. multiflora Thunb. is the highest,18.12%.It showscolchicine is a a suitable method of2n gametes. Through comprehensive analysis and comparisonof different germplasm optimal induction conditions are different, but the concentration of0.15%,0.20%of colchicine could induced better.4. There are50hybrid combinations and only24obtained hybrid fruit, accounting for48.0%.261flowers were pollinated, get90hybrid fruit, total fruit rate was34.48%, a total of514hybridsharvest germination150, the total rate of29.18%germination, seedling64, assembly seedling rate12.45%.5. In the distant hybridization process, the introduction of new varieties of modern rosesobserved.In the modern rose, Frist blush and Princesse de Mon aco are better and the hybridizationrate of fruit than other varieties, while Charles de gaulle is weak and should be selectivelyeliminated. If abortion is before fertilization, embryo rescue methods can be used.