Progeny Test At Nursery Stage And SSR Polymorphism Detection For Several Mating Combinations Of Poplar

At present, poplars are popular in plain area of China. However, due to unitary poplarvariety in huge plantations, two big problems (low genetic diversity and weak ecological bufferpower) have arisen. To solve these problems above, enlarging the number of poplar variety mightbe the best choice. Therefore, more efforts should focus on interspecies crossing and varietyselection for tree breeders. In this paper,3mating types including interspecies cross, intraspeciescross, and open pollination were made in poplar. Progeny test at nursery stage was conducted forthese hybrids. The genetic diversity for each mating combination was also detected based on SSRmarkers. The main results are as follows:The impact of cold storage place on poplar pollen viability: The pollens of3genotypes ofPopulus simonii were stored in two places,4℃refrigerator and4℃cold storage. The pollenviabilities were measured by means of pollen germination in MS medium. The results showedthat, with the increase of storage time, the pollen viability gradually decreased. In comparison,pollens stored in4℃cold storage might be more durable than that in4℃refrigerator. Pollenviability could keep10%after3months storage in4℃refrigerator; While stored in4℃coldstorage, pollen viability could maintain10%after seven months storage.The Crossability of Poplar:5combinations were obtained by controlled pollination,including3combinations of interspecies hybridization and2combinations of intraspecifichybridization. The Crossability of intraspecific hybridization was higher than that of intraspecifichybridization. The the seed germination after1a storage in4℃cold storage was also tested.Among5combinations, seeds from3interspecies hybridization combinations could store longer,their seed germination rate could maintain above30%, and2combinations of them (2#,3#)could keep above60%.Clonal test of poplar hybrids at nursery stage: Based on the growth data of2hybridcombinations (3#,4#) from2test sites (Siyang and Zhenjiang), the variations amongcombinations and test site were analyzed. A significant difference was found existing amongcombinations and clones, therefore parentage selection and the clone selection were possible. Incomparison of growth (tree height and ground diameter), Intraspecific hybridization (4#) wasfaster than intersectional hybridization (3#). Based on clonal test data from2sites,22cloneswere selected for further test.SSR polymorphism comparison among3mating types in poplar: The genetic diversities of5mating combinations in poplar were analyzed by using12SSR markers. Overall, the geneticdiversity of interspecies combination (2#) was the highest, its observed heterozygosity and genetic diversity index are0.7530and0.4410respectively. Followed by intraspecies combination,with open pollination progenies the lowest.