Study On The Genetic Diversity Of Chrysanthemum Cultivars By AFLP Markers

The germplasm of Dendranthema grandiflorum originated from China. It is one of the ten top traditional flowers in China. China is not only the original producing area of wild species of D. grandiflorum, but also has cultivated numerous cultivars of D.grandiflorum after long periods of natural selection and artificial cultivation. At present, the phylogenetic research work of D.grandiflorum is mainly concentrated on the typological status and the classification of cultivars by morphologic observation, cytologic and molecular biologic technique. However, there is little work reported on the interspecies relationships.To offer more scientific evidences for cultivar classification at the level of gemome and enrich the phylogenetic study of D.grandiflorum, we applied the AFLP silver-staining technique and the method of UPGMA cluster to analyze 45 D.grandiflorum cultivars collected from Kaifeng,Henan Province.The main results are shown as follows:1. A better way to extract D.grandiflorum genome was used and the high quality DNA obtained in this way can make follow-up experiments possible.2. A reaction system that is fitting for the classification of D.grandiflorum cultivars was set up, and the legible AFLP fingerprint was obtained.3. The genetic diversity and relationship of 45 D.grandiflorum cultivars were analyzed by AFLP (Amplified Fragment Length Polymorphism) silver-staining protocol.AFLP fingerprinting of 45 D.grandiflorum cultivars with ten pairs E+3/M+3 primers selected from 35 pairs revealed a total number of 486 unambiguous bands, of which 451 ones were polymorphic and 45.1 polymorphic bands per pair of primer were produced on average. The polymorphism frequency was 92.80%. This result showed the abundant diversities of restriction sitea among D.grandiflorum cultivars studied. As analyzed by DPSv3.01,the Nei's genetic distance of 45 D.grandiflorum cultivars ranged from 0.36000 to 0.86237, and the average distance was 0. 611185.These D.grandiflorum cultivars were divided into six groups by UPGMA(unweighted pair group method with arithmetic average) based on Nei's genetic distances. The genetic relationship of 45 D.grandiflorum cultivars was analyzed using the different coefficient.4. Comparison of the genetic diversity obtained from this experiment shows that the genetic diversity level of D.grandiflorum cultivars with the same original producing area was very high. This suggested that frequent artificial exchanges of D.grandiflorum cultivars among areas resulted complex genetic backgroud of D.grandiflorum cultivars with the same original producing area.It is powerful supplement for morphological classification that directly used genotype charactoristics in cultivar classification research.5. Results show that the AFLP silver-staining technique could be used to study the genetic diversity of cultivars.