GENETIC AND CLONAL DIVERSITY IN KOREAN POPULATIONS OF VITEX ROTUNDIFOLIA (VERBENACEAE)

Vitex rotundifolia Lf. is a woody perennial and has sexual and asexual modes of reproduction. Allozyme study was conducted on 550 plants in 13 Korean populations. The levels of genetic variability and divergenc e within and among populations, respectively, are considerably lower a nd higher than the mean values for woody plants with similar life hist ory traits. Mean percentage of polymorphic loci (pp), mean number of a lleles per locus (Ap), and mean genetic diversity (Hep) within populat ions of V. rotundifolia were: 16.7%, 1.21, and 0.047. On average, abou t 79% of the total variation in V. rotundifolia was common to all popu lations (mean G(ST)=0.208). In addition, significant differences in al lele frequencies among populations were found in all polymorphic loci examined (P<0.001). On the other hand, levels of genotypic diversity w ithin and among populations were moderate. About 44% (18/41) of multil ocus genotypes were ''local genotypes'' (genotypes occurring in only o ne population), whereas only one ''widespread genotype'' (genotypes oc curring in more than 75% of the populations) were detected. The mean n umber of multilocus genotypes per population (G) and mean genotypic di versity index (D-G) were 8.4 and 0.74, respectively. Most common multi locus genotypes found in populations were homozygous for five polymorp hic loci. The abundance of ramets of these genets is responsible for t he low levels of expected heterozygosity within populations. The resul ts indicate that clonal reproduction may act as an enhancer of genetic drift by reducing effective size of local populations of V. rotundifo lia.