Phylogenetic, ecological and sensory characterization of Coffea dactylifera, a wild coffee from the Democratic Republic of Congo

Abstract

Background and Aims Coffee is one of the world's most valuable crops and supports the livelihoods of millions, yet it is increasingly threatened by climate change. Diversifying currently cultivated varieties is crucial for the sector's long-term sustainability. Wild coffee species may carry traits critical for climate resilience but remain largely unexplored. This study provides a first multidisciplinary assessment of Coffea dactylifera, a wild species endemic to the Democratic Republic of Congo (DRC), by comparing its phylogeny, climate niche, morphology and sensory profile with those of the wild relatives of Arabica (C. arabica) and Robusta (C. canephora) coffee.Methods We sampled wild C. dactylifera from the DRC and gathered occurrence data. A consensus phylogenetic tree was constructed using ASTRAL-III, based on DArTseq polymorphic genetic markers, and including data from 22 species. Climate niche modelling used filtered occurrence data and bioclimatic variables. Twelve morphological traits were assessed, encompassing leaf morphology, bean characteristics and plant architectural traits. The sensory quality of coffee beans was evaluated using the Fine Robusta Standards and Protocols.Key Results Coffea dactylifera was identified as a sister species to C. anthonyi, as part of the Coffea eugenioides group. It is adapted to high annual temperatures and low climate seasonality, typical of the lowland forests in Central Africa, where it grows sympatrically with C. canephora. In terms of morphology, it displays a more compact growth form and leaf characteristics that distinguish it from sympatric C. canephora individuals. Sensory evaluation revealed an average score of 78.75 points marked by the 'brown sugar' descriptor, intense sweet aftertaste and syrupy mouthfeel.Conclusions C. dactylifera may contribute to climate-resilient coffee breeding. Its genetic proximity to cultivated species, climate niche, compact growth form and promising sensory profile highlight its relevance for conservation and potential use in breeding.