Isozyme diversity and genetic structure of barrenwort (Berberidaceae) populations

Genetic diversity in 36 populations of eighteen species of the genus Epimedium, including sixteen species of section Diphyllon collected from China and two species of section Epimedium collected from Germany was studied using isozyme variation at 11 loci for six enzyme systems (EST, GLU, PGM, PRX, GPI, and SOD). The mean number of alleles per locus (Ap) showed little variation, ranging from 2.09 to 2.73. The mean percentage of polymorphic loci (P) of the eighteen species was high, ranging from 72.73% to 100%. The mean expected heterozygosity (He) ranged from 0.229 to 0.479 of 36 populations studied. Intrapopulational genetic diversity (HT) was 0.5981 while interpopulational genetic diversity (HS) was only 0.3534. The dendrogram of 36 populations studied obtained, using genetic distances among taxa. Obvious grouping of populations consistent with taxonomic species was found in the cluster analysis, confirmed that the eighteen species studied were natural, with a clear boundary between each other. Based on the dendrogram, the phylogenic relationships of Epimedium species are in agreement with the flower size were found, and it was inferred that China should be the original centre of genus Epimedium.

► Genetic diversity of Epimedium was studied by isozyme variation of six enzyme systems.
► High genetic variability was observed at the species and population level in Epimedium.
► Low genetic differentiation was observed between species in genus Epimedium.
► The phylogenic relationships of Epimedium are in agreement with the flower size.