Format: ORAL

Maria Alejandra Serna Snchez1,2,*, Eric J Fuchs2,3and Adam P Karremans1

1 Lankester Botanical Garden (JBL), University of Costa Rica (UCR), P.O. Box 302-7050, Cartago, Costa Rica 2 Escuela de Biología, Universidad de Costa Rica, San José 11501-2060, Costa Rica 3 Laboratorio Binacional de Análisis y Síntesis Ecológica, UNAM-UCR, México-Costa Rica * Corresponding author: maria.serna@ucr.ac.cr

In Costa Rica, around a dozen species of wild Vanilla, including commercially significant ones such as Vanilla planifolia Andrews, V. odorata C. Presl, and V. pompona Schiede, are present, yet information regarding their population genetics is limited. It is suggested that genetic diversity in Vanilla populations may be low due to their potential formation by a few individuals with clonal reproduction. Nevertheless, wild populations may harbor genetic variants important for genetic crop improvement or conservation efforts. Despite Vanilla pompona is listed as endangered by the IUCN, the lack of studies on genetic diversity and population structure hinders its management and conservation. As other Vanilla species, V. pompona depends on pollinators for sexual reproduction, and the interactions among the plant, its pollinators, and dispersers shape the genetic diversity of this Vanilla species. To assess the genetic diversity and structure of wild V. pompona populations, 117 individuals from 8 populations along the Pacific region of Costa Rica were sampled. Microsatellites (SSRs) previously proposed in the literature for different Vanilla species were used; of the 28 SSRs tested, 18 proved transferable, and 12 were polymorphic. High genetic diversity was observed in wild V. pompona populations (HT = 0.588) with moderate genetic structure (FST = 0.194), and populations in the central and northern Pacific showed the least genetic distance. As suggested earlier, greater genetic diversity was evident among populations rather than within, mainly due to their high degree of clonal propagation. The high genetic diversity could be explained by their presence in extensively preserved forests, favoring large effective population sizes over extended periods, thereby mitigating the reducing effects of genetic drift. This study is essential to guide ex situ and in vitro preservation strategies by providing a clear description of genetic diversity in wild Vanilla populations.