Origin and genetic differentiation of pink-flowered Sorbus hybrids

Allopolyploidy combined with apomixis is a partnership that generates novel species in many plant taxa, including the genus Sorbus. Uhrinová et al. use chloroplast and nuclear markers as well as flow cytometry to reveal phylogenetic relationships among pink-flowered Sorbus hybrids and their parental species in the Western Carpathians.

Neighbour-net graph of the studied Sorbus taxa based on AFLP data. — Neighbour-net graph of the studied *Sorbus* taxa based on AFLP data. Chloroplast haplotypes of *S. zuzanae* and *S. haljamovae* referred to in the text are indicated in brackets. The white circle represents one sample of *S. aria* and the black circle one sample of *S. caeruleomontana*in the cluster of *S. haljamovae* and *S. zuzanae*. Bootstrap support for major clades is shown as percentages (>60 %) based on 1000 replicates.

In contrast to the predominantly diploid S. aucuparia and S. aria, the parental species S. chamaemespilus and all hybrid taxa were found to be polyploid and predominantly apomictic. The data suggest that multiple hybridization events in the West-Carpathian Sorbus have led to the formation of separate, partially reproductively isolated genetic lineages, which may or may not be discriminated morphologically.

This paper is part of the Annals of Botany Special Issue on Polyploidy in Ecology and Evolution. It will be free access until October 2017, then available only to subscribers until August 2018 when it will be free access again.