Research On Excellent Individual Plant Breeding And Cold Resistance Of Fraxinus Chinensis Roxb

With the improvement of the living standard,people begin to pay attentio n to the protection and health function of urban greening tree species, but als o focus on the diversity of urban greening tree species. Rich and colorful gre en configuration can not only increase the urban’s ecological environment co nstruction, but also establish a brand effect for urban, which brings a good ec onomic effect. This study takes Beijing city ash as the research foundation, st udy the breeding of ash species, This paper has done the following research.1. Investigation on the phenological period found the longest green period of Fraxinus chinensis was up to 260 days, and only 220 days around the shortest day. Green period of lobular type Fraxinus chinensis was generally longer than large Leaved ash.Green period of deep color Fraxinus chinensis was generally long than shallow color Fraxinus chinensis.Green period of lanceolate Fraxinus chinensis was longer than the round leaf.2. Phenotypic diversity investigation of 74 strains Fraxinus. showed that leaf petiole length, leaf thickness, leaf color and other traits had higher coefficient of variation, generally more than 40%, among this,petiole length was up to 58.69%. however, leaf color, leaf base shape and other traits had lower index of diversity, lower than 1, and low diversity index showed that the phenotypic characters were not affected by environment.3. The orthogonal design was used to optimize SSR-PCR amplification system on Fraxinus chinensis most suitable SSR-PCR system for Fraxinus was established. In order to study the genetic diversity of white wax, using SSR molecular marker for the Fraxinus chinensis for genetic diversity analysis, through 17 primers of 74 strains selected Fraxinus chinese detection analysis,totally 145 alleles were observed among which,133(91%)were polymorphic.the number of DNA bands per primer ranged from 5 to 11 and with the average of 8.5.clustering analysis for Fraxinus of 74.they were initially clustered into 5 groups with coefficient 0.73.4. The selected Franxinus chinese is divided into 5 categories, cold resistance experiment of Fraxinus species, measuring the electrolyte leakage of Franxinus chinese leaves under low temperature treatment, the Logistic fitting effect was good, using it to calculate half semilethal temperature, the winter resistance was higher,the value of LT50 was smaller, on the other hand, cold resistance was weak.In summary, Fraxinus chinensis phenological study and phenotypic diversity survey found it was similar to the cluster analysis of SSR marker.So Fraxinus chinensis could be divided into five categories, which green period of the optimum shape Fraxinus chinensis was up to 260 days and it had the most cold tolerant and could better adapt to environmental changes. The results of this study would provide effective reference for future breeding of Fraxinus chinensis.