Analysis of genetic diversity of sweetpotato landraces in China

Chino. 用RAPD、ISSR及AFLP分子标记，对来自中国安徽、福建、河南和广东4省的48个甘薯地方品种进行遗传多样性分析。用30个RAPD引物、14个ISSR引物和9对AFLP引物分别扩增出227条、249条和260条多态性带。从多态性带的数量和实验稳定性看，AFLP标记优于RAPD和ISSR标记。3种分子标记得出的结果，均揭示中国甘薯地方品种的遗传变异十分丰富，支持中国是甘薯的次生多样性中心的观点。品种遗传变异的地区间差异比较表明，广东地区的地方品种遗传变异高于其余3省，并且达极显著差异水平，从分子水平揭示广东应是中国甘薯的最早引入地，并向周边省及内陆地区扩散。研究发现，由3种标记产生的聚类图存在一些差异，但将3种标记产生的多态性带结合产生的聚类图可以很好地揭示48个地方品种的亲缘关系，所有品种聚为两大类，一类以8个广东地方品种为主，另一类由剩余的8个广东地方品种和其余3省的32个地方品种组成。因此，在进行甘薯育种时应重点考虑广东地方品种的利用。

Inglés. Genetic diversity of 48 sweetpotato landraces, randomly sampled from 4 regions （Anhui, Fujian, Henan and Guangdong）in China, was analyzed using RAPD, ISSR and AFLP markers. Both 30 RAPD and 14 ISSR primers and 9 AFLP primer combinations generated 227, 249 and 260 polymorphic bands, respectively. AFLPs were better than RAPDs and ISSRs in terms of the number of polymorphic bands detected and the experimental stability. These three molecular markers revealed the similar results that Chinese landraces possess high genetic diversity, and the genetic variation of Guangdong landraces was significantly (at 0.01 level) higher than that of the landraces from other three regions. These results support the hypothesis that China was the secondary center of sweetpotato diversity and also showed that Guangdong was the earliest region where sweetpotato was introduced to China. In this study, the combined RAPDs, ISSRs and AFLPs dataset appeared to be appropriate in resolving the sweetpotato varietal relationships. These landraces can be divided into two groups by UPGMA cluster based on genetic distances, one mainly includes 8 landraces from Guangdong, and another consists of the remaining landraces from Guangdong and landraces from the other three regions. Thus, the utilization of Guangdong landraces should be specially considered in sweetpotato breeding.