Get access

Low genetic differentiation among seasonal cohorts in Senecio vulgaris as revealed by amplified fragment length polymorphism analysis

Authors

  • P. Haldimann,

    Corresponding author
    1. Département de Biologie, Section Ecologie & Evolution, Université de Fribourg, Fribourg, Switzerland
      P. Haldimann. *Present address: Institute of Plant Sciences, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland. Tel. +41 31 631 4959; Fax: +41 31 332 2059; E-mail: pierre.haldimann@ips.unibe.ch
    Search for more papers by this author
  • T. Steinger,

    1. Département de Biologie, Section Ecologie & Evolution, Université de Fribourg, Fribourg, Switzerland
    Search for more papers by this author
  • H. Müller-Schärer

    1. Département de Biologie, Section Ecologie & Evolution, Université de Fribourg, Fribourg, Switzerland
    Search for more papers by this author

P. Haldimann. *Present address: Institute of Plant Sciences, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland. Tel. +41 31 631 4959; Fax: +41 31 332 2059; E-mail: pierre.haldimann@ips.unibe.ch

Abstract

Common groundsel, Senecio vulgaris (Asteraceae), is a highly selfing semelparous ephemeral weed that belongs to the few plant species in central Europe capable of growing, flowering and fruiting all year round. In temperate climates, flowering S. vulgaris cohorts were found to appear up to three times per year. Using amplified fragment length polymorphism (AFLP) molecular markers we examined temporal genetic differentiation among spring, summer and autumn cohorts at each of seven sites located in two regions in Switzerland. Strong genetic differentiation among cohorts may indicate the existence of seasonal races of S. vulgaris, reproductively isolated by nonoverlapping flowering phenologies. Analysis of molecular variance (amova) revealed that < 2.5% of the AFLP variation resided among cohorts within sites, whereas there was significant genetic differentiation among plants from different sites (15.6%) and among individuals within cohorts (81.9%). Significant genetic differentiation was also observed between the two regions. Isolation-by-distance was found on a regional scale, but not on a local scale. Gene flow was estimated to be ≈ 15-fold higher among cohorts within sites than among sites. We further found, on average, similar levels of genetic diversity within the three seasonal cohorts. The results of this study demonstrate that season of growth represents a weak barrier for genetic exchange among S. vulgaris populations and does not affect molecular variance. Therefore, there is no evidence for the existence of seasonally specialized races of S. vulgaris. We discuss some implications of the results for the biological control of S. vulgaris using a native rust fungus.

Get access to the full text of this article

Ancillary