Isozyme and morphological diversity within apomictic and sexual taxa of the Ranunculus auricomus complex

 In 17 populations of the tetraploid agamospecies R. variabilis, 10 enzyme systems have been studied by horizontal starch gel electrophoresis, and compared to previous data of 3 populations of the diploid sexual species R. notabilis. Allozymic and genotypic diversity of 12 polymorphic loci, and multilocus genotype diversity in R. variabilis compares to other apomictic taxa, confirming the assumed apomictic mode of reproduction previously found in 3 populations. A cluster analysis based on genetic distance values separated the two taxa, the populations of southeastern Austria sympatric with R. notabilis showing no closer relationships to the sexual species than the allopatric ones. The R. variabilis populations of the circumalpine regions are separated as a rather uniform group, those of the Bohemian massif as another, more heterogeneous group. This geographic differentiation is mainly due to genotypic variation, which is higher in the Bohemian massif than in the circumalpine group, and lower in areas where R. variabilis is sympatric with R. notabilis. Proportion of multilocus genotypes within populations (G/N), genotype diversity (D), and genotype evenness (E) measures indicate facultative recombination events with fixation and clonal reproduction of new recombined genotypes, which is regarded as the most important factor for the evolution of new lineages in goldilocks. Morphometric data of the R. variabilis and R. notabilis populations studied by cluster and principal coordinate analyses clearly separated the two taxa, and indicated a slight geographic differentiation with in R. variabilis corresponding to the results of isozyme data. A principal coordinate analysis of R. variabilis individuals based on stem and fruit characters showed a clinal variation, but no clear separation of groups. The variation found in this PCoA is almost completely covered from the most widespread clone (genotype I), and also from individual genotypes. The implications of the results on different species concepts for apomicts are discussed. For R. variabilis, no taxonomic conclusions can be drawn from the present data set. Received December 15, 1999 Accepted November 15, 2000