【作者】 贺学勤；

【导师】 刘庆昌；

【作者基本信息】 中国农业大学 ， 作物遗传育种， 2004， 博士

【摘要】 本研究通过形态标记和分子标记(RAPD、ISSR和AFLP)的方法，首次对中国甘薯地方品种的遗传多样性进行了系统分析，所使用的品种共计108份，其中中国地方品种100份，分别来自广东、福建、浙江、广西、四川、湖北6个省，育成品种8份，获得的主要结果如下： 1．用区分甘薯品种最基本的9个形态特征：株型、茎端茸毛、基部分枝、干物质含量、叶形、叶色、薯皮色、薯肉色、薯形，可以将104份甘薯品种完全区分开，表明中国甘薯地方品种形态变异丰富，其中福建和广东的地方品种形态变异较大，且地方品种形态多样性高于育成品种。基于形态特征产生的聚类图与已知育成品种的系谱图不吻合。 2．用30个RAPD引物、14个ISSR引物和9对AFLP引物对108份甘薯品种进行扩增，分别扩增出218条、239条和245条多态性带，可将108份甘薯品种完全区分开。AFLP在揭示多态性水平和实验的稳定性上高于RAPD和ISSR，表明AFLP可以作为甘薯遗传多样性分析的首选标记。 3．根据ISSR标记产生的聚类图与育成品种系谱图完全吻合，表明ISSR可以有效地鉴定已知亲缘关系的品种。综合3种分子标记的数据对108份甘薯品种进行聚类分析，可将供试材料分为4个组群，且与育成品种系谱图吻合。 4 根据RAPD、ISSR和AFLP计算得到的遗传距离，表明地方品种间遗传距离变异幅度大，分别为0.0537～0.9418、0.1678～1.4800和0.0227～0.9676，平均遗传距离分别为0.3594、0.5725和0.4754，从分子水平上证实中国是甘薯次生多样性中心。 5．对不同地区内的地方品种间的平均遗传距离进行比较分析，表明广东地区内品种间遗传变异程度最高，而且广东地方品种与其余地区的地方品种间遗传距离较大，认为甘薯最早从中国广东地区引入，并以此为中心向周边和内陆地区扩散。 6 综合3种分子标记得到育成品种与地方品种间的平均遗传距离为0.5269，并且广东的地方品种与育成品种遗传距离最大。因此，在今后甘薯亲本选配和品种保护上，应重点考虑该地区的地方品种。更多还原

【Abstract】 This paper describes, for the first time, the analysis of genetic diversity among sweetpotato landraces in China as revealed by morphological traits and molecular markers (RAPD, ISSR and AFLP). The sweetpotato accessions used in this study included 100 landraces from 6 provinces, Guangdong, Fujian, Zhejiang, Guangxi, Sichuan and Hubei in China and 8 breeding lines. The main results obtained are as follows:1. One hundred and four sweetpotato accessions were distinguished clearly based on 9 morphological traits, plant type, pubescence on vine, plant branch, dry weight, leaf shape, leaf color, root skin color, root fresh color and root shape, suggesting that Chinese sweetpotato landraces possessed sufficient genetic variation. Of these landraces, the landraces from Fujian had the highest level of variation. Chinese sweetpotato landraces had higher level of genetic diversity than the breeding lines. The dendrogram of the breeding lines based on morphological traits was not in agreement with known origin.2. Both 30 RAPD and 14 ISSR primers and 9 AFLP primer combinations were used for assessing genetic diversity among 108 sweetpotato accessions, and generated 218, 239 and 24S polymorphic bands, respectively. AFLPs were better than RAPDs and ISSRs in terms of the number of polymorphic bands and me experimental stability.3. The dendrogram of the breeding lines based on ISSRs agreed better with known origin man those based on RAPDs and AFLPs, suggesting that ISSRs are powerful markers for identifying accessions with known origin. The dendrogram based on the combined RAPDs, ISSRs and AFLPs dataset appeared to be appropriate in resolving relationships of the sweetpotato accessions. By using this approach, 108 sweetpotato accessions could be divided into four groups, and 6 of 8 breeding lines with known origin were clustered together.4. The genetic distances between landraces revealed by RAPDs, ISSRs and AFLPs differed greatly, being 0.0537-0.9418, 0.1678-1.4800 and 0.0227-0.9676, respectively, with the mean genetic distances of 0.3594, 0.5725 and 0.4754, respectively. These results supported the viewpoint that China is a secondary diversity center of sweetpotato.5. Based on the 3 molecular markers, landraces from Guangdong had the highest level of genetic variation in 6 provinces. Meanwhile, the genetic distances between Guangdong and the other 5 provinces were larger than those between the other 5 provinces. These results provided the support that sweetpotato was firstly introduced to Guangdong in china, from which sweetpotato was dispersed to other regions of China.6. The mean genetic distance between the Chinese sweetpotato landraces and the breeding lines calculated by the combined RAPDs, ISSRs and AFLPs dataset was 0.5269. Moreover, the landraces from Guangdong were most distantly related to the breeding lines in 6 provinces. Thus, the utilization and protection of the landraces from Guangdong should be emphasized in sweetpotato breeding.更多还原