The domestication and dispersal of the cultivated ramie (Boehmeria nivea (L.) Gaud. in Freyc.) determined by nuclear SSR marker analysis

Ramie (Boehmeria nivea) was domesticated in China. However, the geographic region of domestication is not exactly known. Genetic diversity and population structure of ramie and their wild relatives were assessed using microsatellite markers. The 8 microsatellite primers revealed 96 alleles in 50 ramie populations, with an average of 10.25 alleles per locus. Cultivated ramie gene pool harbors approximately 82.9 % of the SSR diversity presented in wild B. nivea var. nivea. It is suggested that ramie has experienced a relatively moderate domestication bottleneck. The distribution of genetic diversity shows that genetic diversity is relatively high in populations along the Yangtze River compared to the peripheral ones. The scatter plots of principal coordinates analysis indicated that there are three well-supported varieties in B. nivea. The NJ tree and the distribution of genetic diversity showed that ramie has been domesticated in the middle and lower regions of the Yangtze valley, and populations in Sichuan province have been introduced from this region, forming naturalized populations.