VARIATION IN THE POPULATION GENETIC-STRUCTURE OF 2 CYCLAMEN SPECIES ON THE ISLAND OF CORSICA

Cyclamen repandum and C. hederifolium occur in sympatry in many sites across their distributions but flower at different times. A previous c ontrolled pollination experiment on plants of the two species collecte d on the island of Corsica showed no evidence of inbreeding depression over all measured life cycle stages in C. repandum, whereas C. hederi folium showed inbreeding depression (multiplicative delta = 0.49) on f ruit maturation and seed production. This suggests that C. repandum ma y have a greater history of inbreeding than C. hederifolium. In this p aper, we examine whether within-population heterozygosity and among-po pulation differentiation on Corsica are consistent with the hypothesis that C. repandum is more inbred than C. hederifolium. Cyclamen hederi folium showed a higher percentage of polymorphic loci, mean number of alleles per locus and mean observed heterozygosity than C. repandum. C yclamen repandum showed higher among population differentiation (F-ST= 0.415) than C. hederifolium (F-ST=0.131). The within-population fixati on index was greater in C. repandum (F-IS=0.658) than in C. hederifoli um (F-IS=0.329). Cyclamen repandum thus appears to have a greater hist ory of inbreeding than C. hederifolium. The variation in the mating sy stem of the two species is discussed in relation to their sympatric oc currence. and data from previous work on the population genetic struct ure of island populations of other geographically restricted Cyclamen species.