Allozyme segregation and inter-cytotype reproductive barriers in the polyploid complex Centaurea jacea

O J Hardy, M de Loose, X Vekemans, P Meerts

    Research output: Contribution to journalA1: Web of Science-articlepeer-review

    Abstract

    In eastern Belgium, diploid and tetraploid knapweeds (Centaurea jacea L. s. l.) show a parapatric distribution with a contact zone. To compare the success of inter- and intra-cytotype crosses, and to investigate the pattern of allozyme segregation, controlled crosses involving plants from this contact zone were performed. Polysomic inheritance at two loci was observed in tetraploids, suggesting an autopolyploid origin. Two crosses allowed the detection of double reduction events in tetraploids at one locus, but no such event was detected among the 217 progenies. Null alleles were detected in tetraploids at two loci. Both cytotypes were highly self-incompatible. Inter-cytotype crosses were much less successful than intra-cytotype crosses in terms of seed set (five-fold reduction) and germination rates (three-fold reduction), suggesting a 'triploid block' effect. Progenies from inter-cytotype crosses most often had the maternal cytotype and resulted from selfing or pollen contamination. However, six triploids were detected. The significance of these results for the understanding of the geographical distribution of the cytotypes and inter-cytotype gene flow is discussed.
    Original languageEnglish
    JournalHeredity
    Volume87
    Issue numberPt 2
    Pages (from-to)136-45
    Number of pages10
    ISSN0018-067X
    Publication statusPublished - 2001

    Keywords

    • Alleles
    • Asteraceae
    • Crosses, Genetic
    • Gene Frequency
    • Genetic Markers
    • Isoenzymes
    • Polyploidy

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