Studies On Genetic Diversity And Phylogenetic Relationship Of Dendranthema And Its Related Genera

Several representative taxa of Dendranthema and its related genera, maintained at the Chrysanthemum Germplasm Resource Preserving Center, Nanjing Agricultural University, were used in this study, morphological analysis, ISSR and SRAP analysis were conducted. The genetic diversity and phylogenetic relationship of Dendranthema and its related genera and the different populations of wild species of Dendranthema were studied based on above data. The results were as follows:1,Morphological characteristics also was used to study the genetic diversity of Dendranthema and its related genera.There was a rich genetic diversity among them, and different diversities in different characteristics and different materials. The leaf characteristic was of great variability. And plant types,stem colour,shape and trichome constitute together the abundant genetic diverse of stem. The highest genetic diversity were observed on flower traits, of which the coefficients of variation of ray floret number,length and width were up to 91.52%,108.99% and 110.92%. The results of principle component analysis(PCA) showed that the variations of morphological characters of Dendranthema and its related genera, may be caused mainly by the ray floret,tubular flower and inflorescence of flower traits, leaf trichome,leaf fissure,stipule,blade profile of leaf traits and plant type and plant height of stem traits.2,Molecular markers (ISSR and SRAP) were used to study the genetic relationship and diversity among Dendranthema and its related genera. ISSR fingerprinting revealed the polymorphism frequency was 97.0%, and SRAP was 99.0%. This indicated a rich genetic diversity of Dendranthema and its related genera.The genetic distance among them ranged from 0.0488 to 0.2829, showed a closer relationship to each other. Cluster analysis showed that the 39 materials were clustered into 4 clusters. The first cluster included all the species of Dendranthema and the most of Ajania. The second cluster included the species of Artemisia, Tanacetum, Chrysanthemum, Argyanthemum, Leucanthemu, Nipponanthemum and two species of Ajania (Aj. salicifolia and Ajania tripinnatisecta). Ar. sieversiana and Cr. chinense, having a distant relationship to other species, were clustered as the other two clusters, respectively. Dendranthema was closed to Ajania, Artemisia, Chrysanthemum, Tanacetum, Argyanthemum, while was far away from Leucanthemu, Nipponanthemum and Crossostephium.3,Morphological characteristics was used to study the genetic diversity among different populations of wild species of Dendranthema. The results showed that: Morphology characteristics had considerable variances and there was a rich genetic diversity among different population of wild species of Dendranthema; The greatest genetic variation in the leaf length/leafstalk length, and the lowest in the diameter of disc-flowers and the length stamens; The results of principle component analysis(PCA) showed that the variations of morphological characters of different geographical populations, may be caused mainly by the leafstalk length,the leaf length/leafstalk length,the inflorescence diameter,the ray floret length,the ray floret width and the ray floret length/ray floret width.4,The molecular markers of ISSR and SRAP were used to analyze of genetic diversity among different population of wild species of Dendranthema. The results showed that there was a rich genetic diversity among different population of wild species of Dendranthema, and that the polymorphism information of SRAP was higher than that of ISSR. But there was no significant relationship between the geographical distribution and genetic diversity of wild species of Dendranthema.As for D. japonense and D. zawadskii, the ISSR fingerprinting revealed the polymorphism frequency was 91.9%, and SRAP fingerprinting was 97.5%; The genetic distances ranged from 0.0887 to 0.615 5. The UPGMA dendrogram suggested that it can separate D. japonense (or it's varieties) from D. zawadskii (or it's varieties).As for D. indicum, ISSR primers revealed the polymorphism frequency was 92.5%, and SRAP fingerprinting was 98%; The genetic distance ranged from 0.2117 to 0.4949. The UPGMA dendrogram suggested that populations of Sichuan Chendu and Jiangsu Nanjin had the highest genetic relationship, while, populations of them and Fujian Wuyi Mountain had a relatively low genetic relationship.