AFLP analysis of genetic diversity of Jatropha curcas grown in Hainan, China

Amplified fragment length polymorphism (AFLP) was used to determine the genetic diversity among 38 populations of Jatropha curcas L. grown in a seed source trial in Hainan Province of China. The populations studied consisted of one source from Indonesia and 37 sources from the main cultivating areas of jatropha in China, viz. Guangdong (1), Guangxi (10), Guizhou (4), Hainan (6), Sichuan (8) and Yunnan (8). Nine AFLP primer combinations were used to generate a total of 246 fragments, of which 72 (26.99%) were polymorphic. Three-marker attributes: polymorphism information content (PIC), marker index (MI) and resolving power (RP), were all found to be reliable to determine the discriminatory power of the nine primer combinations. The Jaccard's similarity coefficient showed a high similarity range from 0.866 to 0.977, suggesting a low genetic diversity among the 38 populations. The UPGMA-based dendrogram and biplot of a principal component analysis did not reveal a clear pattern of groupings by geographic locations of the seed sources; populations from across different provinces were mixing in the same groups. The low genetic diversity and a lack of variation pattern among the populations in China suggest that it is necessary to import new germplasm preferably from the species' natural distribution range to broaden the genetic base for improvement program.