Evolutionary history and genetic diversity of apomictic allopolyploids in Hieracium s.str. (Asteraceae): morphological versus genomic features

Premise of the Study

The origin of allopolyploids is believed to shape their evolutionary potential, ecology and geographical ranges. Morphologically distinct apomictic types sharing the same parental species belong to the most challenging groups of polyploids. We evaluated the origins and variation of two triploid taxa (Hieracium pallidiflorum, H. picroides) presumably derived from the same diploid parental pair (H. intybaceum, H. prenanthoides).

Methods

We used a suite of approaches ranging from morphological, phylogenetic (three unlinked molecular markers) and cytogenetic analyses (in situ hybridization) to genome size screening and genome skimming.

Key Results

Genotyping proved the expected parentage of all analyzed accessions of H. pallidiflorum and H. picroides and revealed that nearly all of them originated independently. Genome sizes and genome dosage largely corresponded to morphology whereas the maternal origin of the allopolyploids had no discernable effect. Po...