Sammanfattning

We tested two predictions of the hypothesis that competition between self-pollen may mitigate negative genetic effects of inbreeding in plants: (1) intense competition among self-pollen increases offspring fitness; and (2) pollen competition reduces the measured strength of inbreeding depression. We used Collinsia heterophylla (Plantaginaceae), an annual with a mixed mating system, to perform controlled crosses in which we varied both the size of the pollen load and the source of pollen (self vs. outcross). Fitness of selfed offspring was higher in the high pollen-load treatment. Our second prediction was also upheld: inbreeding depression was, on average, lower when large pollen loads were applied (11%) relative to the low pollen-load treatment (28%). The reduction was significant for two fitness components relatively late in the life-cycle: number of surviving seedlings and pollen-tube growth rate in vitro. These findings suggest that intermittent inbreeding, which leads to self-fertilization in plants with genetic loads, may select for traits that enhance pollen competition.

Nyckelord

mating-system evolution; mixed-mating system; pollen-load size; prezygotic selection; self-pollination

Publicerad i

Journal of Evolutionary Biology
2007, Volym: 20, nummer: 2, sidor: 737-749
Utgivare: BLACKWELL PUBLISHING

UKÄ forskningsämne

Ekologi
Genetik
Evolutionsbiologi


Publikationens identifierare

DOI: https://doi.org/10.1111/j.1420-9101.2006.01233.x

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/42096