The Selection Of Superior Individuals From Planted Forest's Open Pollination Progeny Of Eucommia Ulmoides Oliver

Eucommia ulmoides Oliver,the deciduous tree of Eucommia?Eucommiaceae?endemic to China,is not only a precious Chinese herbal medicine,but also the most important gum source tree species in temperate zone.Breeding excellent varieties of E.ulmoides is an important basic work in the development of its resources.It takes a long time to develop E.ulmoides varieties by conventional breeding method,which cannot meet the demand of production.Combination method of marker-assisted selection?MAS?and conventional method can shorten breeding cycle and improve the efficiency of E.ulmoides breeding.In this study,the one-year-old free pollination progeny of E.ulmoides plantation were used as experimental materials,superior seedlings were selected from about 300,000one-year-old free pollinated progeny.The phenotypic traits of superior seedlings were measured and the variation were analyzed.Six phenotypic traits?e.g seedling height?were used to select superior seedlings of each single trait as the primary superior individuals.Based on the previous study of the high-density genetic linkage map and the important quantitative trait genes of E.ulmoides,molecular markers closely related to the target traits QTL were screened to establish molecular marker-assisted selection method,the primary superior individuals were then re-selected by molecular marker-assisted selection.According to different breeding objectives,the re-selected superior individuals with each single trait was final selected.The main results and conclusions are described as follows:1.The superior seedlings were selected from one-year-old free pollination progeny by seedling height and ground diameter.A total of 120 superior seedlings were selected.2.The CV of rutin content?RC?,chlorogenic acid content?CA?and gutta content?GC?of superior seedlings were larger than other traits.The CV of the RC was the highest,up to99.82%,while the CV of seedling height?SH?was the smallest,which was only about4.98%.The range of variation of RC was 0.02⁵.24 mg.g^-1,the range of variation of SH was 1.25¹.73m.3.The correlation among target traits of superior seedlings was analyzed,the results showed that there was a significant positive correlation between chlorogenic acid and rutin content of superior seedlings.Tree height and ground diameter had positive correlation of superior individuals,the same as chlorogenic acid content and tree height.The correlation of among other target traits was not significant or negative.Subsequent research can be based on the results of correlation analysis among the target traits to improve one or more traits at the same time,which can reduce the workload of selecting superior individuals and improve the selection efficiency of breeding.4.According to the correlation between the phenotypic value of superior seedlings and effect value of the associated molecular marker or combinations,a total of five molecular markers or combinations with high detection efficiency were selected,which were related to tree height?DZ200-350 and em5me7-530?,ground diameter?em15me23-360?,leaf yield?em31me26-160?,content of Eu-rubber?em49me3-150?,content of chlorogenic acid and rutin?em7me28-240?.5.Combined with the results of primary superior individuals for each single trait and marker assisted selection,49 individuals for tree height,17 individuals for ground diameter,25 individuals for leaf yield,23 individuals for leaf Eu-rubber content,22 individuals for leaf chlorogenic acid contents and 21 individuals for leaf rutin contents were identified as superior individuals.6.According to different breeding objectives and the results of re-selected superior individuals for each single trait were final selected.Twelve individuals of high medicinal traits,11 individuals of high Eu-rubber traits and 11 individuals of high growth traits were identified as final superior individuals.