用RAPD、ISSR和AFLP标记分析系谱关系明确的甘薯品种的亲缘关系

The Use of RAPD,ISSR and AFLP Markers for Analyzing Genetic Relationships among Sweetpotato Cultivars with Known Origin

用RAPD、ISSR和AFLP标记对系谱关系明确的7个甘薯品种进行了亲缘关系分析。24个RAPD引物、14个ISSR引物和9对AFLP引物分别扩增出173、174和168条多态性带。3种分子标记在检测甘薯品种间遗传差异上相关程度高，其中RAPD与ISSR之间的相关系数最大为0．9328。用ISSR标记估计的品种间遗传距离为0．1286～1．0932，平均0．4883．大于其余2个标记的估计值。3种分子标记皆可揭示甘薯品种的亲缘关系，其中ISSR标记产生的聚类图与系谱图最吻合，认为ISSR标记更适于分析甘薯品种的亲缘关系。

Sweetpotato, Ipomoea batatas （ L. ） Lam., is an important crop as food, feed and industrial materials grown worldwide. Because of its many biological complexities such as natural heterozygote and cross-incompatibility, the analysis of the genetic relationships among cultivars is of interest not only for germplasm conservation but also for breeding purposes. Molecular techniques have been used broadly for germplasm characterization, variety identification, phylogenetic study and diversity analysis. There has been no report on analyzing genetic relationships among sweetpotato cultivars with known origin using molecular markers. In the present study, genetic relationships among seven sweetpotato cultivars with known origin were analysed using RAPD, ISSR and AFLP markers （ Fig. 1 ）. Twenty-four RAPD primers, 14 ISSR primers and 9 AFLP primer pairs generated 173, 174 and 168 polymorphic bands, respectively （Fig.2, Table 1）. For detecting the genetic differences among sweetpotato cultivars, the correlations among RAPD, ISSR and AFLP markers were significant with the highest correlation coefficient between RAPD and ISSR markers （0.9328）. The ISSR-based genetic distances among the 7 sweetpotato cultivars, ranging from 0. 1286 to 1.0932 with an average of 0.4883, were higher than those calculated with the other two markers. The dendrograms based on RAPD, ISSR and AFLP markers could separately detect genetic relationships of the 7 sweetpotato cultivars and the ISSR-based dendrogram was the best in agreement with their known origin, suggesting that ISSR is the powerful marker for analyzing genetic relationships among sweetpotato cultivars （Fig. 3）.