Breeding system and inbreeding depression in the rare orchid, Platanthera praeclara, in a fragmented grassland landscape

• Published in: Botany Vol. 96; no. 3; pp. 151 - 159
• Main Authors: Travers, Steven E, Anderson, Kirk, Vitt, Pati, Harris, Marion O
• Format: Journal Article
• Language: English
• Published: NRC Research Press 01.03.2018
• Subjects: autopollinisation; conservation des plantes; endogamie; Growth; inbreeding; Methods; orchid; Orchids; orchidée; Plant breeding; plant breeding systems; plant conservation; self-pollination; systèmes de croisement des plantes
• ISSN: 1916-2790; 1916-2804
• DOI: 10.1139/cjb-2017-0104

An important consequence of self-compatibility in plants is that self-pollination can have deleterious effects on plant fitness because of inbreeding. We conducted a hand pollination experiment under field conditions to measure the magnitude of inbreeding depression associated with self-pollination in the rare western prairie fringed-orchid Platanthera praeclara Sheviak and Bowles. By comparing capsules and seeds resulting from cross versus self-pollination treatments, we determined that self-pollination reduces seed quality while having no detectable effect on capsule production or seed numbers. A smaller percentage of seeds resulting from self-pollination contained an embryo (18%) relative to seeds from cross-pollination (46%). Seeds that had an embryo were scored for the size of the embryo, small or large. A smaller proportion of seeds from self-pollination contained a large embryo (75%) relative to seeds from cross-pollination (92%). These results suggest that sexual reproduction and recruitment in this rare plant are dependent on the frequency of pollinator visitations that result in outcrossing.