Construction Of DNA Fingerprint Database And Analysis Of Genetic Diversity For Varieties (Lines) Of Melon(Cucumis Melo L.)

Melon(Cucumis melo L.2n=24) is a kind of trail herbaceous plant which belonging to Cucumis, Cucurbitaceae. Melon is one of the most important fruit and vegetable crops in the world. Since1990s, the melon industry has developed rapidly, also, the cultivation and production of melon has been rising. At present, the phenomenon of homonym and synonyms in melon industry of our China are widespread, which could cause variety authenticity issues. Also, because of the unstrictness in breeding, processing, storage and other aspects, there are many seed quality problems, such as poor varietal purity. There are many reasons for these problems, and now the effects of these problems in melon production are tremendous. In order to solve the disputes and confusions in the market during the course of melon seed operating, it’s necessary to establish DNA fingerprint database of melon, which could provide technical supports for the identifications of varietal purity and authenticity. At the same time, as the second largest originating center of melon in the world, China owns rich melon material resources, so it’s important to enhance the basis study of melon and establish an information platform about the public melon germplasm genetic relationship. In this study, we used SSR molecular marker technology and selected SSR core primers, also, established the fingerprint database of melon varieties (lines). That could provide a theoretical basis for the melon standard fingerprint database and technical supports for identifications of melon varieties and seed purity.In this study, we chose20representative melon varieties (lines), selected1219pairs of SSR primers and obtained470pairs of polymorphic primers. Considering of many factors, such as the statistical difficulties of amplified bands, contents of polymorphism information (PIC), integration of genetic linkage map (ICUGI,2011, http://www.icugi.org/.),18pairs of primers with rich amplified polymorphic were select as core primers to amplify471tested materials. Each pair of primers could detect4-14polymorphic bands, and the average were9bands. Also, the average of polymorphism information contents was0.68with the range of0.55-0.82.Based on the amplification of18pairs of primers, fingerprint codes for each material in471melon varieties (lines) were established, which could differ from each other. Also, fingerprint QR codes of each material were constructed, and there were17groups of materials with the same fingerprint code, involving52materials that accounted for11%of the tested materials, and the identification rate reached89%.Based on162sites of18pairs of core primers, we obtained the cluster analysis pictures of471materials, with the similarity coefficients between0.67-0.99.105materials were extracted for the second cluster analysis, and the similarity coefficients were between0.70-0.99, also, the test materials could be divided into4categories at the genetic similarity coefficient of0.79. The results indicated that SSR clustering results could reflect the phylogenetic relationships of the tested materials.