The impact of hybridization on populations of selected willow taxa in Central Europe

Dr. Radim J. Vašut, Assistant Professor at Palacký University in Olomouc, Czech Republic gives the lecture Hybridization in willows: The impact of hybridization on populations of selected willow taxa in Central Europe.

Zoom hlekkur: https://eu01web.zoom.us/j/66074173012

Abstract: 

Willows are generally known for their ability for extensive hybridization. Taxonomists described myriads of hybrid taxa in willows, including triple hybrids; the most known hybrid complexes were studied using different molecular techniques and partly described patterns of hybridization in the genus. We also obtained information on introgressive hybridization from studies in poplars. However, many interesting patterns observed in nature remained undescribed, and furthermore many described hybrids seem to be fake hybrids.  

In the past 15 years, together with my students, we aimed at understanding genetic diversity of threaten willow taxa of Central Europe (especially Czechia). Employing different molecular markers (previously microsats, recently genome-wide DArTseq genotyping) we are able to describe different patterns of hybridization in willow species. Some species obligatedly do not cross with other species although they have high chance, for example, Salix herbacea and probably Salix bicolor. The opposite extreme is extensive hybridization leading to species extinction and “dissolving” the rare species in hybrid swarm consisting of hybrids between 2-3 species (a case study in Salix myrtilloides). Some locally common species hybridize only occasionally, and in the case of endangered taxa, the hybridization does not cause any threat for the species. Whereas some very common taxa seem to be “threatened” by extensive asymmetric introgressive hybridization, which is the case of common cracking willow (Salix euxina = S. fragilis auct.).  

In my talk, I want to present different cases of hybridization that we observed in willow populations in Central Europe, especially from the point of view of conservation genetics and plant systematics. Some of these patterns probably represent local phenomena but some are likely general patterns with consequences for willow taxonomy and nomenclature.