Université de Sherbrooke
Candidat M.Sc.
superviseur(e): Nadia Tahiri
Début: 2023-09-01
Fin: 2025-08-31

Projet

{From Climate to Caffeine: Environmental Influences on Wild \textit{Coffea} Species in Madagascar
Caffeine is a key secondary metabolite in \textit{Coffea} species, functioning in plant defense and beverage quality. While decaffeination is often chemical, naturally low-caffeine species offer a sustainable alternative. This study examines environmental determinants of caffeine content in wild Madagascan \textit{Coffea} species using integrated genomic, geographic, and environmental data. A two-stage machine learning framework combined binary classification for caffeine presence with regression to estimate content. Feature selection and multicollinearity filtering retained 20 ecologically relevant predictors. October and January precipitation, February maximum temperature, and temperature seasonality emerged as dominant climatic drivers of caffeine biosynthesis. SHAP analysis revealed nonlinear, context-specific interactions among variables. Despite substantial geographic variation, no significant correlation was observed between genetic and geographic distances, suggesting ecological rather than spatial structuring of trait evolution. These results underscore the role of seasonal climate stress in caffeine regulation and adaptive significance in heterogeneous environments. The outcomes provide a foundation for selecting low-caffeine varieties and guiding conservation in changing climates.