The formation and maintenance of odd ploidy level cytotypes in the heteroploid system and their contribution to the heteroploid gene flow in invasive perennial species

Polyploidy is one of the crucial evolutionary factors in the evolution of vascular plants. Polyploid cytotypes are mostly reproductively isolated from their diploid counterparts; however, there exists the possibility of gene exchange between different ploidies/species via heteroploid geneflow. The heteroploid gene exchange might be mediated through the odd and aneuploid cytotypes, which evolved via hybridisation but also de novo via the fusion of reduced and unreduced gametes. The primary focus of the thesis will be to review knowledge about the formation of odd cytotypes in heteroploid systems and evaluate their contribution to gene exchange between given ploidies. The particular focus will be on gene flow between higher ploidy levels in perennial invasive species complexes. Attention will also be paid to mechanisms enabling their maintenance in the population and the consequence of their long term persistence on between ploidy (species) hybridisation on their invasive potential. Key words: odd ploidy level, invasive plants, hybridization, life strateg