Genetic variability and morphology of tri- and tetraploid members of the Sorbus aria complex in northern Bavaria

Abstract

. (2017): Genetic variability and morphology of tri-and tetraploid members of the Sorbus aria complex in northern Bavaria. -Preslia 89: 275-290.The Sorbus aria complex in the Franconian Jura, northern Bavaria, consists of the sexual diploid S. aria s. str. and putative apomictic polyploids, among them S. collina and S. danubialis. Here, the genetic and cytotypic structure of the S. aria complex and the proportion of clonal versus variable genotypes with a special focus on S. collina are studied using nuclear microsatellite markers, flow cytometry and multivariate morphometrics. In the Franconian Jura the tetraploid S. collina is the most frequent taxon in the S. aria complex. It consists of six closely related clones and a high number of unique genotypes, which were found in 70% of the populations studied. Morphologically, most of the clones and the unique tetraploid genotypes are not significantly differentiated. Therefore, all of them could be assigned to S. collina. Mechanisms that could result in the high number of genotypes within S. collina are accumulations of mutations, remnant sexuality, multiple polyploidization events and backcrossing. The results show that S. collina is a genetically quite variable facultative apomictic taxon. Triploids were identified sporadically and the microsatellites pointed to an origin from repeated hybridization events between diploid S. aria s. str. and S. collina. K e y w o r d s:

Apomictic Mountain Whitebeam (Sorbus austriaca, Rosaceae) Comprises Several Genetically and Morphologically Divergent Lineages

“…The genetic data revealed a clear divergence among (groups of) populations included in different allotetraploid apomictic lineages that originated in various parts of South-Eastern and Central Europe. Our results thus support previous findings that hybridisation, polyploidization, and apomixis are the main drivers of Sorbus diversification, at least in Europe [ 33 , 34 , 36 , 82 ].…”

Cytotype variation, cryptic diversity and hybridization in Ranunculus sect. Batrachium revealed by flow cytometry and chromosome numbers

“…In an attempt to change this disappointing state of knowledge, we decided to analyse the variation in ploidy level and genome size in an extensive set of Batrachium populations using flow cytometry (FCM), which (i) is an efficient tool for analysing a large number of individuals rapidly, allowing to reveal the structure of populations and to detect rare cytotypes and hybrids, (ii) is frequently used in studies of evolutionarily and taxonomically intricate groups of plants, including polyploid and hybridogenous complexes (e.g. Suda et al 2010, Trávníček et al 2011a, Chumová et al 2015, Flatscher et al 2015, Lepší et al 2015, Bressler et al 2017, Feulner et al 2017 and homoploid plants (Loureiro et al 2010, Prančl et al 2014, (iii) has been successfully used as a basic method for taxonomic determination and delimitation of other complex aquatic taxa, such as Callitriche (Prančl et al 2014) and Nymphaea (Volkova et al 2010, Kabátová et al 2014, and (iv) has never been used to investigate Batrachium, with the exception of a single R. trichophyllus population (Hidalgo et al 2015). We used flow cytometry combined with chromosome counting to improve our understanding and identification of water-crowfoots in central Europe.…”

Hybridization and introgression of native and foreignSorbustree species in unique environments of protected mountainous areas

“…This high genetic variability, together with the cross-propagation system, confirmed by our study, is characteristic mainly for diploid Sorbus species ( Ludwig et al 2013 ; Hamston et al 2018 ). Although both diploid and triploid populations of S. aria have been found in Central Europe ( Ludwig et al 2013 ; Feulner et al 2017 ), the observed pattern of genetic variability and structure of the tested population of S. aria is a consequence of interbreeding of diploid genomes.…”