Genetic Diversity And Cross Breeding For Cultivars Of Cut Chrysanthemum

Chrysanthemum×morifolium Ramat. belonged to the Chrysanthemum genus, Compositae family. It’s greatly difficult to carried out cultivar classification and genetic diversity research of chrysanthemum, because of their abundant cultivars and morphological variations, and phenotypic traits strongly influenced by environmental factors. We evaluated the introduction adaptability for40single-head-flower chrysanthemum by analytic hierarchy process. And based on DUS investigatation of cut chrysanthemum, their characters variation and correlation were analyzed.56cut chrysanthemum varieties were amplified by SRAP markers to analyze their genetic diversity. At last, we screened chrysanthemum varieties with good synthetical properties or some prominent advantages, to match crossing combinations and analyze their hybridization affinity relationship, which could provide a reference basis for chrysanthemum breeding. All the results of phenotypic combined with molecular markers supplied basic data information for classification, investigation of genetic diversity and cut chrysanthemum breeding. The main research results were as follows:(1) Constract with classic cut chrysanthemum ’Jinba’, we selected15traits about ornamental traits, cultivation features and adaptability, to establish the cut-flower chrysanthemum introduction adaptability evalution system through qualitative and quantitative analytic hierarchy process (AHP). The analysis weight value showed that flower traits were biggest, followed by insect resistance and cultural characteristics, and finally the stem and leaf traits. Comprehensive evaluation founded that ’Jinba’ score ranked second (2.78),19cut chrysanthemum cultivars were introduced successfully by the evalution, which showed good comprehensive traits of cut flower and they were suitable for introduction and spread of large area, which could provide good materials for chrysanthemum breeding.(2) Analysis of variation coefficient and correlation indicated that there were21highly consistent in and specific between chrysanthemum cultivars traits. These21traits could be applied to chrysanthemum identification and classification. The principle component analysis results indicated that larger component value traits contained several flower traits, leaf and stem characters secondly, which were applied to classification appropriately. Extracting principal component contribution rate was low, which explained the diversity of phenotypic traits of cut chrysanthemum in the evolution. Correlation ananlysis results showed that the floral organs existed significant correlation relationship between each character.(3) SRAP-PCR reaction system of cut chrysanthemum is established and optimized by orthogonal design. Out of the100pairs of SRAP primer combinations,14pairs were screened and generated454bands in total with an average of30.21bands per primer pair, of which there were423polymorphic bands in total. The polymorphic percentage was93.17%. PIC (Polymorphism Information Content) value ranged from0.72to0.89, with an average of0.82. These showed an abundant genetic diversity among Chrysanthemum cultivars.(4) The UPGMA clustering analysis of phenotypic characters indicated that56cut chrysanthemum cultivars were divided into flat type group, spoon type group, irregular type group, spoon-flat type group and tube type group. The results approximately corresponded flower diameter, petal type and inflorescence shape. Principle component analysis showed that the significant rate of flower triat was flower diameter, inflorescence shape and petal type as followed. Similarly UPGMA clustering analysis of SRAP showed that56chrysanthemum cultivars were grouped into flat type, spoon-flat type, irregular type and tube type groups. All these results indicated that the classification of cut chrysanthemum by morphology and molecular markers was effective.(5)We carried out self-hybrid, cross breeding and reciprocal cross for two years, the results showed that the self-hybrid was8.03by average rate, among which HH36was highest(28.73), and some cultivars were suitable for male parent. Cross seed setting rate ranged widly, the capitulun average rate was2.25. Among the main female parents,’xiexie’ and ’youxiang’ is highest, among main male parents, C097is highest. After planting germination rate was generally high, with an average of62.3%, and the plantlet formation is more than83%. We analysed the separation and variation of plant stem and leaf traits of’youxiang’×C096hybrid progeny. The large variation range of each individual plant traits showed their background was complex and genotype hybrid degree is high.