Genetic diversity and genetic relatives analysis of tobacco germplasm based on Inter-simple Sequence Repeat (ISSR)

Chino. 本文应用ISSR标记，对烟草属（Nicotiana）4个种30份材料的遗传多样性进行了分析。从70个ISSR引物中共筛选出16个多态性明显、条带清晰、反应稳定的引物，对30个样品DNA共扩增出309条谱带，平均每个引物扩增出19.31条带，多态性条带比率（PPB）达93.20％。种间遗传相似系数在0.26-0.96之间，表现出丰富的遗传多态性。系统聚类结果显示，N．glutinosa和N．suaveolens、N．gossei 3个野生种间存在较大的遗传差异，遗传相似系数在0.29-0.52之间；27份栽培品种种内遗传相似性相对较高，在0.54-0.96之间，显示出栽培种内的遗传基础相对比较狭窄，但其中白肋2l、台烟7号与其他供试材料有较大的遗传差异。ISSR聚类分析表明，当11取值为D=0.475时，可将3个野生种与27份烟草栽培品种明显区分开，反映出种间的遗传差异；当k取值为D=0.776时，可将30份材料分为2个大类、3个小类和6个独立的个类，较好地揭示了烟草属种间或栽培种品种类型间的遗传多样性与亲缘关系，可为烟草遗传育种和遗传连锁图谱构建的杂交亲本选择提供科学依据。本研究还表明，ISSR标记比RAPD标记具有更高的稳定性，在植物遗传多样性的分子标记或克隆研究中，可优先使用ISSR标记。

Inglés. Genetic diversity and relationships of tobacco is a basic part of the research in breeding, origin and evolvement of tobacco. Sixteen primers were selected from 70 ISSR primers, and 309 DNA fragments were amplified from 30 samples including 3 wild species and 27 cultivated species. Of which, 288 fragments were polymorphic （percentage of polymorphic bands was 93.20% ）, and the average number of DNA bands was 19.31 per primer. The genetic similarity among all species ranged from 0.26 to 0.96, and that among 3 wild species N. glutinosa, N. suaveolens and N. Gossei was 0.29- 0.52, while among cultivars was 0.54-0.96, which was comparatively higher. This indicated that the genetic basis was comparatively narrow among the cultivars, except Bailei 21, Taiyan 7 and other materials. The cluster analysis based on ISSR markers showed that the 3 wild species were genetically different from the other 27 cultivars at the level of D = 0.475, and the 30 tobacco accessions could be classified into two groups, three classes and six types at the level of D = 0.776. The results indicated that ISSR technique has better stability than RAPD, and is useful in revealing the genetic diversity and genetic relationships among tobacco species, providing a scientific basis for genetic research and tobacco breeding, as well as for gene cloning of plant germplasm and parents selection in constructing genetic linkage map of tobacco.