This thesis aimed at generating baseline scientific information for the development of breeding programs for Gynandropsis gynandra, an orphan leafy vegetable used in Africa and Asia. After developing a roadmap for orphan leafy vegetables breeding programs, germplasm collection missions were conducted in West Africa to enrich existing collections. Investigations of knowledge, use and management of G. gynandra in seven communities in Benin and Togo allowed identifying communities to be used as entry points for promotion of the species. I also assessed the natural variation in morphology and secondary metabolites production in a collection of accessions from Africa and Asia. Accessions from East Africa, West Africa and Asia had distinct morphological features and metabolic profiles, differences partially reflected at the genomic level. Building the first genetic map in the species allowed identifying candidate genes for plant height, leaf area, flowering time and biosynthesis of provitamin A and vitamin E compounds. This research opens the path towards developing nutrient-rich and high-yielding varieties of G. gynandra for African and Asian markets.