COMPARISON OF QUANTITATIVE GENETIC-VARIATION AND ALLOZYME DIVERSITY WITHIN AND BETWEEN POPULATIONS OF SCABIOSA-CANESCENS AND SCABIOSA-COLUMBARIA

We quantified allozyme diversity and quantitative genetic variation wi thin and between six populations of the locally rare Scabiosa canescen s and the more common and widespread S. columbaria (Dipsacaceae). For the within-population component, we quantified allozyme diversity as t he expected heterozygosity (H-e), followed by a sib analysis to estima te the heritability (h(2)) for eight vegetative and floral characters. There was no consistent association between h(2) and H-e, or between h(2) and current population size. Regarding the between-population com ponent, we compared the overall level of population differentiation fo r the allozymes (F-ST), assumed to be selectively neutral, with the co rresponding estimates for the quantitative traits (Q(ST)) to determine if the marker genes and the polygenic characters have been influenced by the same evolutionary force(s). Differences between estimates of F -ST and Q(ST) for S. canescens were too small to be declared as signif icant, indicating that neutral phenotypic evolution has led to the obs erved differentiation in this species. Our data indicate higher levels of phenotypic differentiation in S. columbaria with values of Q(ST) e xceeding the allozymic F-ST for all traits. This finding indicates a g reat potential for S. columbaria to respond to local selection pressur es, perhaps explaining why this species has a broader ecological ampli tude than S. canescens.