Selection on apomictic lineages of Taraxacum at establishment in a mixed sexual-apomictic population

A species' mode of reproduction, sexual or asexual, will affect its ecology and evolution. In many species, asexuality is related to polyploidy. In Ta raxacum, apomicts are triploid, and sexuals are diploid. To disentangle the effects of ploidy level and reproductive mode on life-history traits, we c ompared established apomictic Taraxacum genotypes with newly synthesized ap omictic genotypes, obtained from diploid-triploid crosses. Diploid-triploid crossing is probably the way that most apomictic lineages originate. New g enotypes had on average a much lower seed set than established genotypes. E stablished genotypes differed on average from new genotypes, in particular under shaded conditions: the established genotypes had longer leaves and fl owered later. The differences between new and established triploids resembl ed the differences that have been found between sexual diploids and establi shed apomictic triploids. We conclude that ploidy differences alone are not directly responsible for observed differences between sexual diploid and a pomictic triploid dandelions.