Ploidy level and origin of the European invasive weed Senecio inaequidens (Asteraceae)

Native to South-Africa, species of the Senecio inaequidens complex are presently invasive in Europe, Australia and South-America. Previously, different ploidy levels have been found in these different areas, with only tetraploid individuals reported in Europe, and only diploids in South-Africa and A...

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Bibliographic Details
Published in:Plant systematics and evolution 2003-11, Vol.243 (1/2), p.59-72
Main Authors: Lafuma, L., Balkwill, K., Imbert, E., Verlaque, R., Maurice, S.
Format: Article
Language:English
Subjects:
Biodiversity and Ecology
Chromosomes
Deoxyribonucleic acid
Diploids
Diploidy
DNA
domain_sde.be.gp
Environmental Sciences
Flow cytometry
Genome size
Genomes
Hybridization
Indigenous species
Invasive plants
Invasive species
Levels
Plants
Ploidies
Ploidy
Polyploidy
Population distributions
Population ecology
Senecio
Tetraploidy
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Summary:Native to South-Africa, species of the Senecio inaequidens complex are presently invasive in Europe, Australia and South-America. Previously, different ploidy levels have been found in these different areas, with only tetraploid individuals reported in Europe, and only diploids in South-Africa and Australia. In the present study chromosome counts and flow cytometry were used to survey DNA ploidy levels in a large sample of 66 native and 21 European invasive populations. One Mexican individual was also added to the study. We found only tetraploid individuals occurring in Europe, whereas both ploidy levels, diploid and tetraploid, were found in South-Africa. Moreover, based on genome size, we suggest that two largely allopatric varieties of diploids exist in South-Africa. The Mexican individual was diploid. We suggest that European tetraploid individuals come from South-Africa and hypothesize that a hybridization event between the two DNA types of diploids occurred in the Lesotho area. The taxonomic difficulties surrounding species of the S. inaequidens complex are briefly discussed.
ISSN:0378-2697
1615-6110
2199-6881
DOI:10.1007/s00606-003-0075-0