Randomly Amplified Polymorphic DNA (RAPD) Variation among and within Cultivated and Wild American Ginseng (Panax quinquefolium L.) Populations

Abstract

The magnitude of genetic differences among and the heterogeneity within cultivated and wild American ginseng populations is unknown. Variation among individual plants from 16 geographically separated, cultivated populations and 21 geographically separated, wild populations were evaluated using RAPD markers. Cultivated populations from the midwestern U.S., the southern U.S., and Canada were examined. Wild populations from the midwestern U.S., the southern U.S., and the eastern U.S. were examined. Polymorphic bands were observed for 15 RAPD primers, which resulted in 100 scored bands. Variation was found within and among populations, indicating that the selected populations are heterogeneous with respect to RAPD markers. The genetic relationships among individual genotypes were estimated using the ratio of discordant bands to total bands scored. Multidimensional scaling of the relationship matrix showed independent clusters corresponding to the geographical and cultural origins of the populations. The integrity of the clusters were confirmed using pooled chi-squares for fragment homogeneity. Average gene diversity (Hs) was calculated for each population sample, and a one-way analysis of variance showed significant differences among populations. Overall, the results demonstrate the usefulness of the RAPD procedure for evaluating genetic relationships and comparing levels of genetic diversity among populations of American ginseng genotypes.