Studies On Germplasm Resources And Genetic Relationship Of Subgenus Of Yulania In China

Magnolia Subgenus of Yulania is an important traditional flower of China. In this study, We gained the current status of species about subgenus of Yulania and cultivated varieties of Magnolia denudata by conducting detailed on-the-spot investigations of the germplasm resources. AFLP fingerprints were made successfully for some species of subgenus Yulania and some varieties of M. denudata. We worked on the classification of species about subgenus Yulania and varieties of M. denudata,and made discussions about the genetic relationship and the evolutional relationship between them, according to the morphology comparisons among the varieties, in conjunction with palynology researches and AFLP molecular-biology means. The principal conclusions as follows:1. According the collection and collation work in our study, there were 52 species of subgenus of Yulania on record at present, in which 18 species were authorization approval,24 new species were be published in scientific literature and 10 species were under suspicion. China as the origin center of subgenus of Yulania in the world, as well as one of the present distribution centers, has 48 native species and 4 alien species.We preparatory acknowledged that there are 40 varieties of M. denudata in China, in which 26 varieties belong to M. denudata, and 14 varieties belong to M.×soulangeana. According to the morphology comparisons among the varieties, we published 11 types of M. denudata which have representative characteristic such as M. denudata'Huangmai'and M. denudata "Yudie" to be as new varieties in this study.We made a clearly classification that 37 varieties of M. denudata were divided into 5 M. denudata and M.×soulangeana groups alternately using a numerical taxonomic method, the results gave us the ideas that extensive characteristics intersections and gradual characteristic transitions among M. denudata and M.×soulangeana were universal situation, on the other way. they also showed that numerical taxonomic analysis might be a great means in the classification researches about varieties of M. denudata.The dendrogram of R clustering analysis showed that characteristics of M. denudata varieties were dispersed independently and had poor relationships among them, which suggested that,30 characteristics of M. denudata varieties we choosed for R clustering analysis were correct, quantization treatments of those characteristics were suitable which given a guarantee for the accuracy and scientificity of the results. Accorrding the contributor ratio from principal component analysis,18 characteristics such as thickness of young branches, leaf bud color and perianth color etc. were cognizanced as the most impacted factors in numerical taxonomic analysis, all of those might made a fine base for the classification researches about varieties of M. denudata.2. Palynology researches of 35 varieties of M. denudata showed that they have similar configuration which their pollen gains were bilateral symmetry, hemimorphic,1-colpate, perprolate(P/E >2), with the size 52.9-61.3μm×21.3-27.6μm, which all belong to pollen gains type N1P3C3, what more, those are the typical characteristic of Subgenus Yulania, but there are still some tiny different were examined about their pollen gains'exine ornamentation (such as the density of perforations and caves, type of exine ornamentation etc.). M. denudata has a cave-shaped exine ornamentation, otherwise, M.×soulangeana. has striate-shaped, helminth-shaped or spine-shaped exine ornamentation. Those results showed that the morphological characteristic of pollen gains exine ornamentation could surely be used as the criteria of classification among varieties of M. denudata.The clustering result of palynology numerical taxonomic showed that varieties in this research were divided into 2 groups clearly:M. denudata and M×soulangeana, which suggested that palynology might be a fine method for species classification, whereas, it was not so sensitive in variety classification which might be as an assistant method only. 3. AFLP fingerprints and dendrogram with high diversity and rich polymorphism were made successfully for 16 species of subgenus Yulania and 39 varieties of M. denudata, what more, DICE or Jaccard coefficient and SM coefficient have been acknowledged as the more authentic methods for dendrogram computing of species and varieties of subgenus Yulania and M. denudata independently.The phylogenetics clustering result of 16 species approved of the classification treatment that M.amoena and M.biondii were in the same group.We acknowledged that M.crassifolius was a mutation of M. wufengensis firstly because of that they have a more closer relationship according the clustering result. Our study didn't approve of the classification treatment David made that M. sinostellata was merged into M. tomentosa, we tended to deal with it as a species of subgenus Yulania individually and be as the same section with M.amoena and M.biondii. We didn't approve of the treatment that M funiushanensis to be as a variety of M.zenii and be merged into M.biondii. The results of AFLP suggested that the sepal-like petal and petal color were defective and not enough for devided sections of subgenus Yulania.The clustering result that 39 varieties were divided into 2 groups:M. denudata and M.×soulangeana, which approve of that provenance might be the first-class standard for variety classification. The clustering also showed that the petal shape had a poor correlation between the similarities among the varities. Varieties from the same areas showed to be clustered together in this study which a conceivable reason might be that they were bred from the same species or varieties of the same areas.Results above showed that AFLP technique could surely be used as an efficacious assistant and referenced method for the classification and identification researches among species and varieties of Yulania on the base of complete understanding of their germplasm development course. 4. Varieties in our research were divided into 2 groups (M. denudata and M.×soulangeana) clearly, according to morphology numerical taxonomic analysis, palynology numerical taxonomic analysis and AFLP technique, all of these results were approved of the treatment for M. denudata classification nowadays, which suggested that these 3 methods were fine assistant means for species classification of Magnolia Subgenus of Yulania and varieties classification of M. denudata.5. Varieties with the same petal color were clustering closely in the dendrograms of palynology numerical taxonomic analysis and AFLP analysis, varieties with the multiple petals were clustering scatteredly however, which suggested that petal color were in a higher lever against to petal shape (multiple petals) as the standard of varieties classification, what more, plenty of research works were indispensable to make petal color and as the secondary classification standard in the future.6. The planting history of Chinese Subgenus Yulania was discovered as early as 2500 years ago, and the culture of Chinese Subgenus Yulania which be as an important content of Chinese traditional flower-culture then has a great development with all kind forms of artistic expression (such as poetry, painting and folk-custom etc).Our research provided a large amount of; useful information not only for thorough comprehending the present resource situation, the biological characteristics and the genetic relationships of subgenus Yulania, but also for supplying credible science data and theory evidences in improving and perfecting the classification system of subgenus and varieties of M. denudata. What more, it also made a substantial foundation for the following work such as resource protection, collection and new germplasm resource development etc. of subgenus Yulania in China.