Morphological variation in sexual and agamospermous <i>Amelanchier</i> (Rosaceae)

Campbell, Christopher S.; Wright, Wesley A.; Vining, Thomas F.; Halteman, William A.

doi:10.1139/b97-829

Cited by 9 publications

(3 citation statements)

References 35 publications

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“…Sorbus -related entities are notorious in taxonomy due to complexity in phenotypes resulting from interspecific hybridization and facultative agamospermy [ 39 , 69 , 70 ]. Apomictic microspecies confound systematic resolution of agamic complexes using nuclear markers [ 71 ]. Phylogenies based on nuclear genes may suffer from paralogue problems and chloroplast markers would work better at the very beginning when no clear ideas are available for classification.…”

Section: Discussionmentioning

confidence: 99%

Phylogeny of Maleae (Rosaceae) Based on Multiple Chloroplast Regions: Implications to Genera Circumscription

Sun

Shi

et al. 2018

BioMed Research International

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Maleae consists of economically and ecologically important plants. However, there are considerable disputes on generic circumscription due to the lack of a reliable phylogeny at generic level. In this study, molecular phylogeny of 35 generally accepted genera in Maleae is established using 15 chloroplast regions. Gillenia is the most basal clade of Maleae, followed by Kageneckia + Lindleya, Vauquelinia, and a typical radiation clade, the core Maleae, suggesting that the proposal of four subtribes is reasonable. In the core Maleae including 31 genera, chloroplast gene data support that the four Malus-related genera should better be merged into one genus and the six Sorbus-related genera would be classified into two genera, whereas all Photinia-related genera should be accepted as distinct genera. Although the phylogenetic relationships among the genera in Maleae are much clearer than before, it is still premature to make a formal taxonomic treatment for these genera.

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Section: Discussionmentioning

confidence: 99%

Phylogeny of Maleae (Rosaceae) Based on Multiple Chloroplast Regions: Implications to Genera Circumscription

Sun

Shi

et al. 2018

BioMed Research International

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“…Sang & al., 1995;Wendel & al., 1995;Aguilar & al., 1999) due to reduced/lacking recombination rate and meiotic paring in the case of non-homologous ITS regions (cf. Campbell & al., 1997;Fehrer & al., 2009;Hörandl & al., 2009;Záveská-Drábková & al., 2009). However, most of the intra-individual polymorphic sites found in the P. alpicola group (excluding P. alpicola s.str.)…”

Section: Discussionmentioning

confidence: 99%

Biosystematic study of the diploid‐polyploid Pilosella alpicola group with variation in breeding system: Patterns and processes

Šingliarová

Hodálová

Mráz

2011

TAXON

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Members of the Pilosella alpicola species group (Asteraceae) are distributed throughout the alpine region of the European mountains (Alps, Carpathians, Balkan mountains). Like other Pilosella species groups (Hieracium subg. Pilosella), the taxonomy and species' relationships are poorly understood mostly due to widespread facultative apomixis, frequent hybridization and polyploidization—the most important phenomena substantially involved in the evolutionary history of the genus. We assessed morphology, ploidy level, variation in breeding system and molecular variation within the P. alpicola group to provide a new taxonomic concept and to clarify evolutionary relationships among species and origin of polyploids. Multivariate morphometric analyses (UPGMA, CDA, PCA) applied on 324 plants originated from 21 populations revealed existence of four well‐separated clusters corresponding to four allopatric taxa: P. alpicola s. str. (Alps), P. rhodopea (Balkan Peninsula, Southern Carpathians), P. serbica (Serbia and Montenegro) and P. ullepitschii (Carpathians). In total, four ploidy levels (2x, 3x, 4x, 5x) were detected among 557 plants analysed from 19 populations by classical chromosome counting and flow cytometric analysis. The tetra‐ and pentaploids of P. alpicola s. str. have an allopatric distribution (Wallis Alps vs. Dolomites, respectively). Four ploidy levels with complex cytogeographic pattern and high frequency of mixed ploidy populations (75%) indicating a primary contact zone were recorded in P. rhodopea. Pilosella ullepitschii and P. serbica are exclusively diploid and are both sexually reproducing. In spite of a clear morphological separation, a molecular analysis (ITS and cpDNA sequences) suggests close relationships and rather recent origin of all studied taxa, except P. alpicola s. str. The latter taxon is an agamospermic allopolyploid that likely originated polytopi cally from a hybridization between P. rhodopea from the Balkans and P. glacialis from the Alps. In contrast to P. alpicola s. str., our data strongly support an autopolyploid origin of P. rhodopea polyploids which reproduced strictly sexually. Pilosella petraea, sometimes treated as a member of the P. alpicola group, differs from the remaining taxa by its conspicuous morphology, ecology and ITS polymorphism and should be removed from the group. Range shifts and extinctions were likely involved in shaping the evolutionary and modern distributional pattern of the group. Our combined methodological approach enabled us to propose a new taxonomic circumscription for the P. alpicola group and revealed auto‐ and allopolyploidization events.

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“…Morphological data collected from the M. section Chloromeles accessions demonstrated continuous variation between the three taxa to which accessions were initially assigned, leading DICKSON et al (1991) to conclude that the name M. coronaria should be applied to all of this material. Similarly polyploid, apomictic Amelanchier laevis WIEGAND was shown not to be subdivided into microspecies by means of statistical analyses of generalized distances calculated from eight morphological descriptors (CAMPBELL et al 1997). These analyses indicated that variation within and between local populations of A. laevis was smaller than in diploid, sexual A. bartramiana (TAUSCH) ROEM., and did not provide evidence for population differentiation in A. laevis.…”

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confidence: 99%

Taxonomy of agamic complexes in plants: A role for metapopulation thinking

Dickinson

1998

Folia Geobot

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The argument is made that species should be comparable with respect to the numbers of genotypes they include, regardless of whether their reproduction is exclusively sexual or not. Specifically, this means recognizing species at a level comparable to that of the section or series, as these are used in genera like Crataegus L. or Taraxacum WEBER ex EH. WIGG. Anticipated advantages of this approach for the taxonomy of agamic complexes include the following: (1) a common basis for communication between taxonomists and population biologists, hence (2) the opportunity to find possible explanations for patterns of variation in theoretical models of population behavior. In addition, (3) revising the hierarchical level at which species are recognized will make it easier to avoid describing species that are paraphyletic, i.e. that include some but not all related genotypes sharing a common ancestor. As an example, revising the hierarchical level at which species are recognized makes it possible to see many agamic complexes as being made up of metapopulations of genotypes that arise and go extinct as habitats become available and then disappear for whatever reason (succession, disturbance, etc.) and at whatever scale (local, regional, continental).Can there be a similar taxonomic approach for both sexually reproducing and agamospermous plants? In responding to the questions posed by the organizers of this forum, it seems appropriate to state some personal premises that form the basis of how I try to do taxonomy in a group in which agamospermy occurs.(1) Species are of critical importance in how we communicate about and interact with the non-human biological world.(2) Species are recognizably distinct from each other, at least at some phenotypic level.(3) If A and B are species, each represented by populations of sexually reproducing individuals, then the more recognizable similarity of individuals of A to each other (compared to the similarity of A and B individuals to each other) is due to their descent, with modification, from a common ancestor that is more recent than the common ancestor of both A and B. The recognizability of species is thus a function of degrees of genealogical relatedness and biological processes like mutation, recombination, and selection.(4) Since diploid, sexually reproducing species have been found to comprise multiple genotypes we should expect that the comparable taxon level in agamosperms should also include multiple genotypes. Forum: Species concept in agamic and autogamic complexes

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Morphological variation in sexual and agamospermous Amelanchier (Rosaceae)

Cited by 9 publications

References 35 publications

Phylogeny of Maleae (Rosaceae) Based on Multiple Chloroplast Regions: Implications to Genera Circumscription

Phylogeny of Maleae (Rosaceae) Based on Multiple Chloroplast Regions: Implications to Genera Circumscription

Biosystematic study of the diploid‐polyploid Pilosella alpicola group with variation in breeding system: Patterns and processes

Taxonomy of agamic complexes in plants: A role for metapopulation thinking

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