title: Effects of pollination and postpollination processes on selfing rate in Mimulus ringens.
abstract: Selfing rates vary widely within and among populations of self-compatible flowering plants. This variation is often attributed to differences in the amount and timing of self and outcross pollen deposition on stigmas, as well as to the influence of postpollination mechanisms that control fertilization success. This study explores the relative importance of pollination and postpollination processes in determining selfing rates in monkeyflower, Mimulus ringens.
  
  
  
  We hand-pollinated flowers on 17 unrelated mothers with pollen from one of three experimental treatments intended to replicate field conditions: (1) simultaneous deposition of 50% self pollen and 50% outcross pollen from 5 unrelated donors; (2) self pollen followed 15 min later by application of an equal amount of outcross pollen from five unrelated donors; and (3) outcross pollen from 5 unrelated donors followed 15 min later by application of an equal amount of self pollen. We genotyped 757 progeny at 8 polymorphic microsatellite loci and used paternity exclusion to determine whether each seedling was selfed or outcrossed.
  
  
  
  When self and outcross pollen arrived simultaneously, and when self pollen arrived 15 min prior to outcross pollen, the observed proportions of self and outcross progeny did not deviate from the expected 1:1 ratio. However, when outcross pollen was applied 15 min prior to self pollen, there was a significant excess of outcross progeny.
  
  
  
  Selfing rate in Mimulus ringens is influenced by small differences in the timing of pollen arrival, but not by nonrandom postpollination sorting.
authors.affiliation: Department of Biological Sciences, P.O. Box 413, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201-0413 USA.
authors.forename: Yuliya B
authors.initials: YB
authors.lastname: Sorin
authors.affiliation: Department of Biology, University of Akron, Akron, Ohio 44325-3908 USA.
authors.forename: Randall J
authors.initials: RJ
authors.lastname: Mitchell
authors.affiliation: Department of Plant Biology, 2502 Miller Plant Sciences, University of Georgia, Athens, Georgia 30602-7271.
authors.forename: Dorset W
authors.initials: DW
authors.lastname: Trapnell
authors.affiliation: Department of Biological Sciences, P.O. Box 413, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201-0413 USA karron@uwm.edu.
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Karron
mesh_terms: D005838:Genotype; D032241:Mimulus / Q000235:genetics / Q000502:physiology*; D011058:Pollen / Q000502:physiology*; D054817:Pollination; D012098:Reproduction; D057945:Self-Fertilization
keywords: monkeyflower; pollen competition; pollination; postpollination; selfing rate; siring success