ISSR analysis of genetic diversity and relationships among sweet potato (lpomoea batatas) landraces in China

摘要

To analyse the genetic diversity and relationships among Chinese sweet potato landraces and cultivars in China, one hundred landraces from six geographical regions of China and eight cultivars were assessed using inter-simple sequence repeat (ISSR) markers. Fourteen ISSR primers generated 239 polymorphic bands with an average of 17 polymorphic bands per primer. A high average genetic distance and wide variation range were found among Chinese landraces, which were also distantly related to the cultivars with an average genetic distance of 0.6428 (range 0.2591 to 1.6428). The UPGMA dendrogram showed the same genetic relationship among the cultivars in agreement with their known origin and the very wide genetic diversity of the Chinese landraces. The cluster analysis classified the materials into two groups: a major and a minor group. The minor group comprised 14 landraces collected mainly in Guangdong and Fujian, and two cultivars (cv. Nancy Hall and cv. Xu78-l) that are distantly related to each other. The major group consisted of the other 92 accessions. These results indicate that the Chinese sweet potato landraces not only exhibit a high level of genetic diversity but also have a different genetic background from cultivars in China.