Karyotype Analysis And Construction Of Fingerprints In Malus Sieversii Infraspecies

Xinjiang Malus sieversii is important germplasm resources, a vulnerable species under state protection(category ii). This species has many good traits and very rich genetic diversity, so it is a kind of excellent germplasm resources, but the classification of the types under species has not been clarified, classified study of them will lay a foundation for scientific development and utilization of the resources. This study use xinjiang wild apple types under species as the research object, taking the classical karyotype analysis method to analyze karyotypes of them and by using SSR molecular marker technique to construct DNA fingerprint to provide scientific basis for further improving the classification methods of wild apple germplasm resources in xinjiang, thus lay a foundation for its development and utilization. The main results were as follows:(1) Twenty-four germplasm types which were collected from Yili and selecting the tender stem, tableting with the improved chromosome preforming methods for the karyotype analysis of the Xinjiang Malus sieversii and the karyotype characteristics were analyzed. Results show: Twenty-four germplasm types which were collected and studied from Yili. Selecting the tender stem, tableting with the improved chromosome preforming methods for the karyotype analys was of the Xinjiang Malus sieversii. According to the chromosome number of different types and the relative length, average arm ratio, the karyotype characteristics were analyzed. All of the twenty-four type under species were diploid, whose chromosome number in all Malus sieversii types were 2n=34. And the length of the chromosome was 3.23 ?m, so they belonged to small chromosomes. The range of the arm ratio was from1.27 to 1.56, and the symmetry the karyotype was in the range of 56.01 %-63.39 %, the most karyotype characteristics was 1A and 1B, 2A and 2B only exist in some few types, the percentage of which was 41.67 %, 37.5 %, 8.33 %, 12.50 %. Viewing the length of the chromosome, except for the xiang-suan and chang-bing wild apple, the rest of the types owned long chromosome(L), middle long chromosome(M2), middle short chromosome(M1), and short chromosome(s), and it was not seen the satellite in them.(2) Do cluster analysis according to different karyotype characteristics of 24 Malus sieversii germplasm types. Results show: 24 kinds of germplasm types were divided into three categories. The first category includes 9 kinds of germplasm types, they had higher karyotype feature similarity, most types' average arm ratio were greater than others, combining evolutionary trend results, found their evolutionary trends were higher than other groups. The second category includes 11 kinds of germplasm types, most karyotype types were 1B, 2A, and 2B. The third category included 4 kinds of germplasm types, their average arm ratio and karyotype asymmetry coefficient were both the minimum, karyotype type belonged to 1A and 1B, all above showed that the genetics of this group was relatively stable.(3) To build the fingerprint of 62 apple germplasm resources in xinjiang based on the SSR molecular marker method, using 12 primers for PCR amplification, screening 4 primers with the best discrimination capability and applying primer combination method to construct DNA fingerprint. In the fingerprint, CH02a08 marker has the best discrimination effect and 40.32 % of researching materials(25) can be separated only by it; Combining CH03d07, MS06g03, CH02a08, CH02b12 primers, 62 apple germplasm resources could be completely separated.(4) Xinjiang wild apple types under species were analyzed combining the features of karyotype with molecular marker map. The karyotype characteristics of 24 types under species had certain differences and compwered with the traditional classification method, it revealed the genetic relationship between them more clearly and the clustering result could reflect the similarities and differences between them better. According to the specific marker loci of the SSR fingerprint, 62 selected materials could be divided into four groups at the genetic similarity coefficient of 0.62. On the basis of the information revealed by two methods, the classification results of 24 types under species was mostly close by them, but also appeared inconsistent results. Therefore, constructed SSR markers in this study is suitable for building apple resources DNA fingerprint database of xinjiang and it can provide the basis for the xinjiang apple resources appraisal.