Reproductive biology and conservation genetics of Serapias vomeracea (Burm.) Briq. (Orchidaceae)

Serapias vomeracea is considered to be a particular example of the deceptive strategy of terrestrialorchids. Information on its reproductive biology and population genetic variation is needed to developconservation strategies. The pollination biology and breeding system were investigated in four populations ofS. vomeracea. Hand-pollination experiments showed that S. vomeracea is self-compatible. Baggedinflorescence produced no fruits; artificial pollination resulted in 89.7–100% fruit set through inducedautogamy, 91.1–100% with geitonogamous, and 89.3–94.4% following xenogamous pollination. Fruit set in theopen-pollinated control ranged from 13.4 to 20.9%. We evaluated the spatial genetic structure of 13 populationsusing five nuclear microsatellite loci. Italian and isle of Corfu populations of S. vomeracea are characterized bya low mean allele number, ranging from 2.4 to 3.8, by intermediate to high heterozygosity levels, ranging from0.50 to 0.71, and by frequent deviations from the Hardy-Weinberg equilibrium (9 out 13 populations). Most ofthe S. vomeracea populations exhibited significant heterozygote excess. The population size reduction is mostprobably the cause of the low genetic variation observed in the populations of S. vomeracea. For the geneticconservation and management of S. vomeracea suitable strategies should be developed based on these data.