EFFECT OF RECURRENT SELFING ON INBREEDING DEPRESSION AND MATING SYSTEM EVOLUTION IN AN AUTOPOLYPLOID PLANT
Article first published online: 21 MAR 2011
© 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.
Volume 65, Issue 7, pages 2038–2049, July 2011
How to Cite
Ozimec, B. and Husband, B. C. (2011), EFFECT OF RECURRENT SELFING ON INBREEDING DEPRESSION AND MATING SYSTEM EVOLUTION IN AN AUTOPOLYPLOID PLANT. Evolution, 65: 2038–2049. doi: 10.1111/j.1558-5646.2011.01259.x
- Issue published online: 5 JUL 2011
- Article first published online: 21 MAR 2011
- Accepted manuscript online: 22 FEB 2011 02:43PM EST
- Received March 5, 2010, Accepted January 21, 2011
- Chamerion angustifolium;
- deleterious mutation;
- mixed mating;
- serial inbreeding
Genome duplication resulting in polyploidy can have significant consequences for the evolution of mating systems. Most theory predicts that self-fertilization will be selectively favored in polyploids; however, many autopolyploids are outcrossing or mixed-mating. Here, we examine the hypothesis that the evolution of selfing is restricted in autopolyploids because the genetic cost of selfing (i.e., inbreeding depression) increases monotonically with successive generations of inbreeding. Using the herbaceous, autotetraploid plant Chamerion angustifolium, we generated populations with different inbreeding coefficients (F= 0, 0.17 and 0.36) through three consecutive generations of selfing and compared their magnitudes of inbreeding depression in a common environment. Mating system estimates for four natural populations confirmed that tetraploid selfing rates (sm= 0.25, SE = 0.02) are similar to those of diploids (sm= 0.12, SE = 0.12; F1,2= 1.34, P= 0.37) indicating that both cytotypes are predominantly outcrossing. Compared to an outbred control line, mean inbreeding depression for seed production, survival, and height (vegetative and total) in the inbred line differed among generations (inbreeding coefficients). Across all stages, inbreeding depression (relative to control) was positively related to generation (inbreeding coefficient). Although the initial costs of inbreeding in extant and newly synthesized polyploids may be low compared to diploids, the monotonic increase in inbreeding depression with repeated inbreeding may limit the extent to which selfing variants are favored.