Abstract: As an important material of industry and new energy resource crop as well as food and forage, increase in production of sweetpotato[Ipomoea batatas (L.) Lam.] is desired, but this goal is often limited by a narrow genetic background of the parents in conventional hybridization. It is, therefore, necessary to assess genetic diversity in main parents of sweetpotato. In this study, 62 main sweetpotato parents in China were assessed by using inter-simple sequence repeat (ISSR) marker to understand their genetic difference for exact parent selection in breeding. Seventeen ISSR primers generated 490 polymorphic bands with an average of 28.8 polymorphic bands per primer, indicating that ISSR marker was one of efficient methods to analyze the genetic diversity of sweetpotato. Wide genetic variations, ranged from 0.158 to 0.924 with an average genetic distance of 0.574, were found among the tested cultivars. The UPGMA cluster analysis classified the materials into 2 groups, domestic and exotic cultivars. These main parents had high genetic diversity, and domestic cultivars were far from exotic cultivars in terms of genetic distance. The genetic diversity of Asian cultivars was higher than that of the cultivars originally from Africa and America. The cultivars from Chinese mainland had the smallest genetic distance (0.419), and were close to the cultivars from Taiwan, China, but far from exotic Asian cultivars. These results suggest that crosses between domestic and exotic parents should be emphasized in sweetpotato breeding in China.

Key words: Sweetpotato, Parents, Genetic diversity, ISSR marker