Format: ORAL

Jeronimo Cid1,2, Alex Papadopulos1,2, Muriel Gros-Bhalthazard3,4, Sylvie Ferrand4, Nathan Wales5, Michael Purugganan4, Oscar Perez-Escobar1, Sidonie Bellot1

1 Royal Botanic Gardens Kew, TW9 3AE Richmond, United Kingdom 2 School of Natural Sciences, Bangor University, Gwynedd, United Kingdom 3 DIADE, University of Montpellier, CIRAD, IRD, Montpellier, France 4 Center for Genomics and Systems Biology (CGSB), New York University Abu Dhabi, Abu Dhabi, UAE 5 Department of Archaeology, University of York, York YO1 7EP, United Kingdom

Palms are distributed along sub-tropical and tropical regions of the world and depended upon by millions of people. As such, ongoing aridification raises concerns for palm conservation and their supported livelihoods, and makes it critical that we gain a deeper understanding of drought adaptation in palms. Comparative studies including model crop species and their more variable wild relatives show great potential to progress the understanding of complex traits such as drought tolerance. A good model to perform such studies is the Phoenixgenus, which includes the culturally and economically important date palm crop (Phoenix dactylifera), and thirteen wild species occurring in habitats that vary in aridity. However, the phylogenetic relationships and species barriers of Phoenixspecies have not been elucidated so far. This slows down understanding of Phoenix evolutionary history and prevents robust estimations of how wild species may suffer from future aridification. Accurate delimitation of species and the inferring of the species relationships in Phoenixhas been impeded by morphological and genetic similarities among species, in some cases resulting from past or ongoing hybridisation. For instance, hybridisation among the Cretan date palm (Phoenix theophrasti) and west African date palm has been documented and is considered the reason for the increased genetic diversity among west African date palm populations. To build accurate phylogenies while solving the delimitation of species within the genus, multidisciplinary research looking at genetic, ecological and morphological information must be undertaken on well identified accessions, and genomic approaches must account for gene flow between species. Here, we infer well-supported phylogenetic relationships in genus Phoenix and clarify the taxonomic status of the Cape Verde date palm by using authoritatively-identified herbarium specimens and gene-flow aware approaches. This will improve our knowledge on the Phoenix system which will aid conservation efforts and in crop development.