Genetic Diversity in Main Parents of Sweetpotato in China as Revealed by ISSR Markers

Sixty-two main parents of sweetpotato [Ipomoea batatas (L.) Lam.] in China were assessed using inter-simple sequence repeat (ISSR) markers to understand their genetic differences. Seventeen ISSR primers generated 490 polymorphic bands with an average of 28.8 polymorphic bands per primer, indicating that ISSR marker was efficient to analyze the genetic diversity of sweetpotato. Wide genetic distances (GDs), ranged from 0.158 to 0.924 with an average of 0.574, were observed among the tested cultivars. The cluster analysis classified the cultivars into domestic and exotic groups using unweighted pair group method with arithmetic mean. The domestic group was distant from the exotic group in terms of GD. The Asian cultivars had higher genetic diversity than the African and American cultivars. The cultivars from Chinese mainland, which had the smallest GD (0.419), were genetically close to the cultivars from Taiwan, China, whereas they had relative larger differences with the cultivars originated from other Asian countries. The results suggested that the crosses between domestic and exotic parents should be emphasized in sweetpotato breeding in China.