Phylogenetic Relationships of the Cultivated Neotropical Palm Bactris gasipaes (Arecaceae) with its Wild Relatives Inferred from Chloroplast and Nuclear DNA Polymorphisms

Abstract

Peach palm (Bactris gasipaes Kunth.) is the only Neotropical palm domesticated since pre-Columbian times. It plays an important role not only at the local level due to its very nutritious fruits, but also in the international market for its gourmet palm heart. Phylogenetic relationships of the peach palm with wild Bactris taxa are still in doubt, and have never been addressed using molecular sequence data. We generated a chloroplast DNA phylogeny using intergenic spacers from a sampling of cultivars of Bactris gasipaes as well as putative wild relatives and other members of the genus Bactris. We estimated phylogenetic relationships using maximum parsimony (MP), maximum likelihood (ML), and Bayesian analysis. Our results indicated a close affinity between three taxa: Bactris gasipaes var. gasipaes, B. gasipaes var. chichagui, and B. riparia. There was no clear differentiation between these three taxa at the level of chloroplast sequences, and they shared a unique inversion that we characterized in this paper. Bactris setulosa, a species potentially related to the Bactris gasipaes complex, appeared highly divergent, and seemed to be a composite taxon with affinities outside the complex. We also investigated nuclear microsatellite polymorphisms at 8 loci within Bactris gasipaes, B. riparia, and B. setulosa, finding a pattern of relationships in agreement with the cpDNA data. The results presented here are important for future studies on domestication and crop improvement of Bactris gasipaes.