Study On Germplasm Resources Of Pear Cultivated In The Protection Section Of Dangshan Anhui By ISSR Technique

Inter-Ismple Sequence Repeat(ISSR)is a new technique of molecular remark. Because of the fingerprint of amplified products may provide a lot of sequence information it was applied widely in the construction of genetic map,discrimination of germplasm resources,discusison of relationships between different biotypes based on microsatelite sequence exist abundantly in genomic DNA to deisgn isngle-chain primer used in the amplification of genomic DNA by polymerase chain reaction(PCR).Currently there were many reports of ISSR analyiss about fruit plant at home and abroad but that about pear germplasm resources had not been found at home.The 26 biotypes of pear germplasm resources cultivated in the protection section Dangshan County,Anhui Province,was studied by ISSR technique in this paper,which is isgnificant to reasonable utilization of germplasm resources and speeding of process of pear breeding.The main results obtained were as follows:1.The 16 primers suitable for the amplification of pear genomic DNAs by ISSR analyiss were screened out from 45 ones used in plant,i.e.Z01,Z04,Z07,Z08,Z09,Z11, Z12,Z13,Z14,Z15,Z16,Z23,Z25,Z29,Z30,Z32.2.The optimal system for analyiss of pear genomic DNAs by ISSR-PCR was established,of which the components of DNA Taq polymerase,Mg²⁺,primer,template DNA and dNTPs was 0.5 U,2.0 mmol/L,0.5μmol/L,40 ng and 0.20 mmol/L respectively in total reaction volume of 25μl.3.The 11 of 26 biotypes could be identified by uisng of DNA fingerprint constructed with the specific bands amplified by selected 5 primers,and the whole 26 biotypes could be discriminated completely by the pattern built up with that amplified by 8 primers.4.The 174 bands were amplified by uisng of 16 primers.The fragment isze was 200bp-2000bp,of which the 150 bands were polymorphic accounting for 86.2%of total bands obtained.The rate of polymorphism amplified with Z01,Z02 and Z25 was the highest,up to 100%,and which with Z09 was the lowest,55.6%.5.According to the cluster analyiss 26 biotypes was divided into different groups and analyzed by F test.There was extreme difference while the whole biotypes was classed into 8 groups and the threshold of distance coefficient was taken at 0.703～0.798 indicating the reasonable clasisfication.The first group includes Dangshansu pear and its 8 mutants, Ehuang,Zaomeisu,Hongxiansu,Xipisu,Cili,Kuerlexiangli,Niitaka,Huangguan clustering at the distance coefficient of 0.703.The second group was Nanguoli.The third group included Hosui,Yali,Zisu.The forth group was Matihuang.The fifth group included Xiangrnianli,Xuehuali.Fusu,Red Bartlett and Pyrus betulaefolia Bunge formed a group respectively.6.Comparing with the stock plant,Dangshansu pear the specific bands was present in its all eight mutants by ISSR analyiss uisng 16 primers.The result showed that 30 bands altered in Xipisu,27 in Lianglizaosu,27 in Biansu,21 in wangsu,14 in Youpisu,13 in Xiusu,12 in Baguaisu,3 in Lengsu.