Genetic diversity of 48 sweetpotato landraces randomly sampled from Anhui,Fujian, Henan and Guangdong provinces in China was analyzed using RAPD, ISSR and AFLP markers. Thirty RAPD primers, 14 ISSR primers and 9 AFLP primer pairs generated 227, 249 and 260 polymorphic bands, respectively. AFLP markers were better than RAPD and ISSR markers in terms of the number of polymorphic bands detected and the experimental stability. These three molecular markers revealed the similar results that Chinese landraces exhibited a high level of genetic diversity, and the genetic variation of Guangdong landraces was significantly higher than those of the landraces from the other three regions. These results supported the hypothesis that China was a secondary center of sweetpotato diversity. The present results also supported the view that sweetpotato was first introduced to Guangdong and from there spread to other regions of China. The dendrogram based on the combined RAPD, ISSR and AFLP dataset could separate the 48 landraces into two groups: One mainly including 8 landraces from Guangdong and the other consisting 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.
