Analysis of genetic diversity and population structure in sweetpotato using SSR markers

Abstract

Sweetpotato, Ipomoea batatas (L.) Lam., is an important food crop worldwide. Large scale evaluation of sweetpotato germplasm for genetic diversity is necessary to analyze the genetic relationship between them and make effective use of them in genetic improvement of this crop. In this study, the genetic diversity of 617 sweetpotato accessions, including 376 landraces and 162 bred varieties from China and 79 introduced varieties from other 11 countries, was assessed using 30 simple sequence repeat (SSR) primer pairs with high polymorphism. Based on the population structure analysis, these sweetpotato accessions were divided into three groups, Group 1, Group 2 and Group 3, which contained 228, 136 and 253 accessions, respectively. The consistent results were obtained by phylogenic analysis and principal coordinate analysis (PCoA). Of the three groups, Group 2 showed the highest level of genetic diversity and were mainly distributed in low-latitude regions. The accessions from South China exhibited the highest level of genetic diversity, which support the hypothesis that Fujian and Guangdong were the earliest regions where sweetpotato was introduced to China. Analysis of molecular variance (AMOVA) indicated that there were significant genetic differentiations between different groups, but low levels of genetic differentiations existed between different origins and accession types. These results provide valuable information for the better utilization of these accessions in sweetpotato breeding.