Analysis Of Genetic Diversity And Relationship Among Chaenomeles Germplasm Using RAPD And AFLP Makers

Chaenomeles was originated in China, there are plentiful of wild genetic resource and cultivars. About the identification, taxonomy of Chaenomeles cultivar types, lots of works have been done, but there is no report about genetic polymorphism and the relationship of Chaenomeles, which limit the use of reasonable of Chaenomeles.In this research, RAPD (Random amplified polymorphic DNA) was used to genome polymorphism analysis of the 12 Chaenomeles cultivar types, which are C.×superba'Crimson and Gold', C.×superba'Changshoule', C.×superba'LüBaoshi', C. speciosa'Toyo Nishiki', C. speciosa'Hongxing', C.×superba'Da Fugui', C.×superba'Hong Baoshi', C.×superba'Fu Changshou', C. japonica'Danbai', C.×superba'Bixue', C. cathayensis'Luofu', C. cathayensis'Changjun'; AFLP(Amplified fragment length polymorphism)was used to genome polymorphism analysis of the 29 Chaenomeles cultivar types, which are C.×superba'Crimson and Gold', C.×superba'Changshoule', C. speciosa'Baochun', C.×superba'LüBaoshi', C. speciosa'Toyo Nishiki', C.×superba'Ziyi', C. speciosa'Fenhuang Mu', C. speciosa'Hongxing', C.×superba'Da Fugui', C.×superba'Hong Baoshi', C.×superba'Fu Changshou', C. japonica'Danbai', C.×superba'Bixue', C. japonica'Dan Fen', C. japonica'Riluo', C. cathayensis'Hongxia', C. cathayensis'Zui Yangfei', C. cathayensis'Luofu', C. cathayensis'Changjun', C. cathayensis'Yipin Xiang', C. speciosa'Xizhao', C.×superba'Yi Hong', C. japonica'Pygmaeus', C.×superba'Fendie', C.×superba'Hongwu', C. japonica'Rubra', C.×superba'Yi Cheng', C.×superba'Jiaoyang', C. japonica'Siji Hong'. By NTSYS-PCR Program, Jaeeard's genetie similarity coeffieients were generated and dendrogram was construeted uesing UMPGA (Unweightedpair-group mathematic analysis), which reveal genetic relationship of Chaenomeles germplasm, qinquired into the relationship and Genetic Polymorphism of Chaenomeles, and to provide some basis to research and manufacture. The main results were as follows:(1)The extraction of genomic DNA was studied on tender leaves of Chaenomeles is contrasted by two methods of conventional CTAB and improved CTAB, and results showed that improved CTAB method was suitable for extracting DNA from tender leaves of Chaenomeles. All things considered improved CTAB was the best method for Chaenomeles genetic DNA from leaves and high quality of genetic DNA was achieved in the end.(2)Random amplified polymorphic DNA (RAPD) was used to analyze the genetic polymophism of 12 Chaenomeles cultivars. Five primers amplified 313 DNA ragments which included special DNA fragments from 12 cultivars. It could also be used to differentiate all cultivars being tested and the UPGMA method may be used to analyze the genetic relationship. The results showed that 12 Chaenomeles cultivars were divided into four cluster groups. The results confirmed that the flower colour has no relationship to the genetic groups, but the Chaenomeles cultivers come from the same family that the relationship is similar. Therefore, the genetic background has effect on the genetic relationship.(3)On the basis of RAPD analysis, more cultivars were added to AFLP markers were used to further assess genetic diversity and relationship of Chaenomeles cultivars. The eight primers combinations(E-AAG+ M-CAA,E-ACA+ M-CAA,E-AAG+ M-CAC,E-AAG+ M-CAG,E-AAG+ M-CAT,E-AAG+ M-CTG,E-ACA+ M-CTT和E-ACG+ M-CTT) could generate 313 fragments from 29 Chaenomeles accessions,of which 288 fragments were polymorphic. The Percentage of polymorphism for six primer combinations was 94.52%. Primer E-AAG/M-CAT showed highest fragment,Polymorphic fragments,percentage of polymorphism,and marker index. This finding was accordance with the results of RAPD analysis. Dendrogram analysis clustered the accessions into four groups: C. speciosa,C. cathayensis,C. japonica and C.×superba.(4)Compared the main Chaenomeles genetic diversity of the research findings of RAPD and AFLP markers, AFLP is the most efficient molecular polymorphism markers in terms of testing the ability of genetic diversity. This experimental study showed that using RAPD and AFLP technology to Chaenomeles species classification is reliable. But does not exclude other classifications, and should be combined with morphological characteristics, Chaenomeles species classification more scientific and more rational and more accurate.On the whole, two types of DNA makers used in the Present study were stabilized and efficient in cultivar identification, estimation of genetic diversity and genetic relationship. The results with two types of markers were consistent.