Ploidy level and breeding system in some populations of Pilosella (Asteraceae) in eastern and southern Slovakia

Anna Krahulcová,František Krahulec

doi:10.33542/tjb2020-1-04

Abstract

The ploidy level/breeding system was determined in following species and hybrids originating from populations of the agamic polyploid complex of Pilosella in Slovakia: P. bauhini (either sexual tetraploids or apomictic pentaploids), P. hoppeana subsp. testimonialis, P. lactucella, P. onegensis (all three taxa diploid and so supposedly sexual), P. officinarum (pentaploids, hexaploids and octoploids, all cytotypes apomictic), P. glomerata (one pentaploid, another plant hexaploid and apomictic), P. macrostolona (apomictic hexaploids), P. schultesii, (mostly tetraploid, one plant an apomictic pentaploid), P. lactucella × P. onegensis (diploid and sexual), P. lactucella × P. aurantiaca (triploid and apomictic) and P. bauhini × P. officinarum (both sexual and apomictic tetraploids, apomictic pentaploids and apomictic hexaploids). The paper provides two karyological novelties in Pilosella: (a) A new hexaploid cytotype was revealed in Pilosella glomerata; (b) The octoploid apomictic and monoclonal plants of Pilosella officinarum were grown from seeds suggesting an occurrence of fruiting octoploid maternal plant(s). Such a cytotype would represent a new highest ploidy level detected in P. officinarum in the field. The cytotypes that were attributed both to P. officinarum and to the hybrids of P. bauhini and P. officinarum differed in a within-population clonal diversity. This effect could result from a different impact of (residual) sexuality and/or a different rate of origin of particular hybrid cytotypes. All findings presented in the paper are compared with published data on Pilosella species that refer preferentially to Slovakia, but also to a broader area in Central Europe.

Highlights

Taxonomic complexity in Pilosella Hill, formerly placed in the genus Hieracium L. s.l., has following reasons (Fehrer et al 2007): (a) diversity in ploidy level, (b) diverse breeding systems, and (c) both past and recent hybridization
The Pilosella alpicola group that is confined to alpine areas, is the third group of taxa that had systematically been explored in Slovakia, including the variation in ploidy level and breeding system (Šingliarová & Mráz 2009; Šingliarová et al 2011)
The sexual tetraploids dominate in Slovakia and Hungary, whereas the apomictic pentaploids prevail in the Czech Republic and Germany (Rotreklová 2004; Rotreklová et al 2005; Marhold et al 2007; Mráz & Šingliarová 2009; Paule et al 2017)

Summary

Introduction

The Pilosella alpicola group that is confined to alpine areas, is the third group of taxa that had systematically been explored in Slovakia, including the variation in ploidy level and breeding system (Šingliarová & Mráz 2009; Šingliarová et al 2011). Both the ploidy level and breeding system were studied in five populations of Pilosella echioides (Lumn.) F. Our present study contributes to the knowledge about ploidy level/chromosome number in altogether twelve taxa and hybrids of Pilosella originating from eastern and southern Slovakia; out of them, the breeding system was examined in seven taxa and three hybrids (Tab. 1). Hereby we aimed at the question, to a what extent is the sexual/apomictic reproduction in particular cytotypes reflected in the clonal diversity assessed by pattern of isozyme phenotypes

Material and Methods

Results

Discussion

Method used