Genetic diversity and population structure of ramie (Boehmeria nivea L.)

Ramie (Boehmeria nivea (L.) Gaudich) is widely used in the manufacture of garments and industrial fabrics. In the present study, 1151 ramie germplasm resources from 13 regions within China, Brazil, Indonesia, India, and Cuba were analyzed for genetic diversity and population structure using 23 simple sequence repeat (SSR) markers and three phenotypic markers to provide baseline information for ramie's breeding and conservation plans. Overall, 117 loci were identified and Shannon's diversity index ranged from 0.3201 to 1.6773 (average, 0.8272). The polymorphism information content varied from 0.1578 to 0.7603 (average, 0.5017), expected heterozygosity from 0.1694 to 0.7815 (average, 0.5282), and genetic diversity from 0.1722 to 0.7884 (average, 0.5228). Genetic diversity was higher in Sichuan, Yunnan, and Guizhou than in the other regions studied. Cluster analysis based on unweighted pair group method with arithmetic mean and genetic distance revealed marked differences between domestic (Chinese) and foreign (other regions) germplasm resources. Population structure analysis also evidenced two groups. Genetic diversity was higher in wild than in domesticated germplasms. Overall, results obtained here will be useful for selecting parents for breeding and performing association analyses in ramie.