Architectural singularities in wild Coffea (Baracoffea) species: integrated morphological perspectives for climate-resilient coffee cultivation

Global coffee production faces increasing threats from climate change, including rising temperatures, prolonged droughts, and spreads of diseases. Wild coffee species, notably those growthing in highly constrained environments in Madagascar, offer a critical genetic resource to address these challenges. Understanding adaptive traits allowing these species to establish into arid environments is essential to implement guid breeding strategies into create resilient coffee varieties. Here, we hypothesize that these wild Coffee species display unique traits compared to other Coffea species, reflecting adaptations to arid and seasonally dry environments. We used the architectural analysis to describe three Baracoffea species and compare them to known cultivated Coffee. Field studies were conducted in two contrasting sites in Madagascar, focusing on three wild coffee species, natively growing into arid environments: Coffea ambongensis, C. bissetiae, and C. boinensis. Structural traits at the whole plant scale were measured across developmental stages using morphological and architectural analyses. Our results suggest that unique traits characterize Barracoffea species, such as rhythmic growth, terminal flowering on short shoots, and species-specific developmental strategies. These findings highlight the architectural diversity of Baracoffea, identify potential key drivers of ecological adaptation and therefore highlights the potential of this group of species for breeding climate- resilient coffee varieties.