Analysis On Phenotypic Characters And Karyotype Of Cymbidium

Chinese Cymbidium, with a high ornamental value in terrestrial, which belongs to Cymbidium andOrchidaceae, is much favored by the masses of the people. As one of the most famous traditionalflowers with extremely cultural characteristics and a history of two thousand years of cultivation.Numerous varieties, abundant morphological variation, relatively complicated genetic background dueto long periods of cultivation, natural selection and artificial cross breeding, which brings greatdifficulties in germplasm resource investigation, classification and identification, as well as theprotection of the varieties in abundant Chinese Cymbidium species. On the basis of investigation ofChinese Cymbidium species in Zhejiang Agriculture and Forestry university orchid resource nursery,the diversity of phenotypic characters and karyotype parameters, cultivars classification are analyzedfrom phenotypic characters and karyotype aspects, expecting for that the research could provide somereference point in varieties protection, choice of hybrid breeding parent, classification and identificationof Chinese Cymbidium. The main results of this text are as follows:1. In order to summarize the diversity and regularity of Chinese Cymbidium that shows inphenotypic characters aspect, the methods of statistics and numerical taxonomy are used to measure andanalyse the82phenotypic characters of90Chinese Cymbidium cultivars.52phenotypic characters,include20quantitative characters,16binary characters and16polynary characters, have been s creenedout that can be suited for the basis of species classification and identification, through thecomprehensive analysis of three aspects of intra-cultivars uniformity test, extra-cultivars diversityanalys is, and R cluster analysis. The result of principal component analysis shows thatflowers-concerned characters are stable relatively, and carry a large proportion of genetic information ofall phenotypic characters, which makes these flowers-concerned characters a major contributor tospecies diversity. In addition, leaf-concerned characters, plant height and pseudobulb etc, also havecertain stability and carry abundant genetic information. These results show that the richness of geneticvariation and the diversity of differentiated direction of phenotypic characters.2. Q cluster analysis results indicate that varieties among these four kinds:Cymbidium sinense, C.ensifolium, C. kanran, C. faberi, have closer affinity, as well as the three kinds: C. goeringii, C.tortisepalum, C.longibracteatum. To some extent, Q cluster analysis can reflect the genetic relationship among varieties, lay foundation of selecting the hybrid parent in cross breeding, improve crosscompatibilities between cross parent, and then increase the success rate of hybridization.3. Analyses of the color-concerned characters conclude that: There is a certain interrelation amongthe veins color of inflorescence base sheath, the color of petals and calyx, pedicel color, bracts color,and spot or patch color of labellum, and it is characterized by a positive correlation. That is to say, thedeeper the color of inflorescence base sheath veins and bracts, the deeper in petals, calyx, pedicel, andthe spot or patch color of labellum. In addition, when the color of inflorescence base sheath veins showsclear and white-green, it is more likely to be the chypre, such as C. tortisepalum ‘xiaoxuesu’.4. On the basis of phenotypic characters test and analysis, chromosome karyotype parameters of28Chinese Cymbidium varieties have been analyzed and summarized, and the results indicate thatchromosome number of all varieties is constant, all of them are diploid, and chromosome satellites arenot observed, that is2n=40. Karyotypes are more symmetric, most of them are1B and2B with some2A and2C. Of all the28varieties, the number of three kinds of karyotypes are: m＞sm＞st. Comparekaryotypes among different species and different petal types, the obvious distribution is not showed up.But, a certain correlation is existed among these three karyotype parameters: the mean of arm ratio, thevariance of arm ratio and the karyotype asymmetry coefficient.5. By calculating correlation coefficient between phenotypic characters and karyotype parameters,it shows that the correlationship between most of the characters and karyotype parameters is little. AndR cluster analysis results show that30variables divide into two groups, one group containsflowers-concerned characters and7of karyotype parameters, the other contains flowers-concernedcharacters, leaf-concerned characters and some of karyotype parameters, to a certain extent, it shows thecloser relationship between flowers-concerned characters and karyotype parameters, flowers-concernedcharacters are more easily affected by karyotype than leaf-concerned characters.