Interspecific gene flow and an intermediate molecular profile of Dyckia julianae (Bromeliaceae), an endemic species from southern Brazil

Abstract

Abstract When related species are distributed in sympatric populations, hybridization may occur. Likewise, one or more of these species may have arisen through historical hybridization between taxa. Here, we aim to elucidate the occurrence of hybridization among three Dyckia spp. (Bromeliaceae) from southern Brazil. We used seven nuclear and six plastid microsatellite loci to assess patterns of genetic diversity, population structure and hybridization in the three species. Furthermore, we performed manual crosses between species to test compatibility and fertility. The results showed that Dyckia julianae has an intermediate molecular profile, low gene flow occurs between Dyckia hebdingii and Dyckia choristaminea and higher gene flow occurs between D. julianae and the other two species. Plastid microsatellites identified 12 haplotypes that are shared among the species. The manual crosses between D. julianae and the other two species produced viable seeds, but no crosses between D. hebdingii and D. choristaminea generated fruits. Our data suggest that the reproductive barrier between D. julianae and the other two species is permeable. Further investigation into the hybrid origin hypothesis of D. julianae should be undertaken, as well as the mechanisms involved in reproductive isolation between D. hebdingii and D. choristaminea.