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Polyploidy and self-compatibility: is there an association?

Authors

  • Barbara K. Mable

    Corresponding author
    1. Department of Botany, University of Guelph, Guelph, Ontario, Canada N1G 2W1
      Author for correspondence: Barbara K. Mable Tel: +1 519 824 4120 ext. 52685 Fax: +1 519 767 1991 Email: bmable@uoguelph.ca
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Author for correspondence: Barbara K. Mable Tel: +1 519 824 4120 ext. 52685 Fax: +1 519 767 1991 Email: bmable@uoguelph.ca

Summary

  • • Researchers have hypothesized that self-compatibility (SC) should be more common in polyploid taxa than their diploid counterparts because of selection for reproductive assurance and/or the expected decline in inbreeding depression associated with having ‘extra’ gene copies. Support for this view has come from an observed breakdown of self-incompatibility (SI) in some species with a gametophytic system (GSI). The purpose of this research was to assess the strength of this relationship across a wider array of SI systems.
  • • A large database, of diploid chromosome numbers, ploidy levels, and types of SI system, was assembled for angiosperm species and used to test for an association between ploidy and SC.
  • • No strong association was found between SC and polyploidy at the level of species or families, and there was no evidence that those having a functional SI system also had fewer polyploid taxa or that most polyploids experience a breakdown in SI.
  • • These results challenge the assumption that self-fertilization is strongly associated with polyploidy and suggest directions for further research on the evolution of polyploidy in relation to SI.

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