【作者】 高文琳；

【导师】 李火根；

【作者基本信息】 南京林业大学 ， 林木遗传育种， 2012， 硕士

【摘要】 杨树是我国中纬度平原地区主要造林树种之一。但目前推广的杨树品种较为单一，遗传多样性低，生态缓冲性较差，亟须扩大杨树品种的遗传基础，拓宽其适生范围。为此，本文以I-69杨为母本，小叶杨、美洲黑杨为父本进行杂交，并对杂交组合子代进行苗期测定，同时，利用SSR分析不同交配组合子代的遗传多样性，期望为今后杨树杂交亲本选配提供参考。主要研究结果如下：不同储藏条件对小叶杨花粉生活力的影响。对小叶杨3个基因型（1#、2#、3#）的花粉，分别贮藏于4℃冰箱与4℃冷库中，分析花粉生活力随储藏时间的变化趋势。结果显示，总体上，随着储藏时间增长，杨树花粉活力逐渐降低。但相比较而言，在贮藏温度同为4℃的条件下，冷库比冰箱保存更为持久。4℃冰箱贮藏条件下，花粉储藏3个月后其生活力可保持10%；而在4℃冷库贮藏条件下，花粉储藏7个月后其生活力仍可保持10%。杨树杂交与杂交可配性分析。通过控制授粉获得5个杂交组合，包括3个美洲黑杨与小叶杨派间杂交组合和2个美洲黑杨种内杂交组合。总体上，美洲黑杨种内杂交可配性明显高于派间杂交。同时，还分析了杨树杂种种子的耐储藏性，4℃冷库中贮藏1a后，杨树派间杂种种子萌发率仍可保持在30%以上，其中，2个组合（2#，3#）种子萌发率可达60%以上。杨树杂交子代苗期无性系测定。对杨树2个杂交组合（3#，4#）子代无性系进行苗期测定，分析不同杂交组合子代苗期生长（苗高、地径）差异，以及同一杂交组合子代在不同地点的生长表现。方差分析结果显示，苗期生长量在不同杂交组合间，以及组合内无性系间差异均达显著或极显著差异，表明开展杂交亲本选配与组合内无性系选择是必要的。美洲黑杨种内杂交组合（4#）子代苗期生长量显著高于杨树派间杂交组合（3#）子代。同一杂交组合子代无性系在两个地点生长量差异较大，地点效应较为明显。根据两个地点的苗期试验结果，对美洲黑杨种内杂交组合（4#）子代无性系进行初选，共选出22个无性系，为下一步多地点林期测定奠定基础。杨树不同杂交组合子代的SSR遗传多样性分析。利用SSR分子标记分析了杨树5个交配组合子代的遗传多样性，包含三种交配类型：派间杂交、种内杂交及自由授粉子代。结果显示，I-69杨×小叶杨2#杂交子代的观察杂合度最高，为0.753；遗传多样性指数最高，为0.441。总体上，与美洲黑杨种内杂交子代相比，杨树派间杂交子代具有更高的遗传多样性。更多还原

【Abstract】 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.更多还原