The main goal of the project is to explain the considerable differences in intensity of natural interspecific hybridization among the Central European Cirsium taxa, i.e., identification of the principal eco-geographic reproductive isolating barriers and estimation of their importance. The genus Cirsium was chosen as a model because the geographical distribution of its hybrids and intensity differences in interspecific hybridization are, compared to other frequently hybridizing genera (Viola, Carex, Verbascum, Epilobium, Salix), the best documented in natural conditions in the Central Europe. Additionally, Cirsium hybrids are easily morphologically determinable, and there are no serious taxonomic problems in this area. Natural interspecific hybridization intensity, expressed by numbers of specimens of hybrids in Czech herbaria, will be correlated with various models of geographical distribution similarities, flowering period overlap, reciprocal ecological affinities, genetic divergence (genome size, AT/GC genomic ratio, sequence of non-coding nrDNA and cpDNA), and hybrid success (pollen viability, seed fertility) of parental taxa in the relatively small but ecologically diversified area of the Czech Republic.

Publications