Isoenzyme diversity in Reynoutria (Polygonaceae) taxa: escape from sterility by hybridization

Abstract. The genus Reynoutria is represented by four taxa in the Czech Republic – R. japonica var. japonica and compacta, R. sachalinensis and R. · bohemica. Using isoenzyme analysis, we determined the degree of genotype variability in all taxa and compared clonesofR. japonicavar. japonica fromthe CzechRepublicwith those fromGreatBritain.While the rarely occurring tetraploid variety R. japonica var. compacta possesses low variability, the octo-ploid female clone of R. japonica var. japonica is genetically uniform in the 93 clones sampled and belongs to the same genotype that is present in the whole Europe. R. japonica var. japonica can be fertilized by the pollen of tetraploid R. sachalinensis and a hexaploid hybridR. · bohemica is produced. In R. sachalinensis, 16 genotypes were found in the 50 clones sampled.R. · bohemica is genetically themost diverse taxon in the study area, with 33 genotypes recorded among 88 clones sampled