Résumé
Photoperiod sensitivity of sorghum landraces allows the synchronization of their flowering time with the end of the rainy season. Sorghum improvement programs have just started considering this trait. Integrating photoperiod sensitivity into a crop model and using a Geographic Information System (GIS) make it possible to identify optimum growing areas for different cultivars by combining varietals traits, climatic uncertainty and farmers' practices. The study of the behavior of 52 landraces in Mali and Burkina Faso shows that early-maturing varieties have a large geographic adaptation area but a very narrow sowing window. On the other hand, photoperiod-sensitive varieties are specifically adapted to a given geographical zone but can cope with a large variation in sowing date, which is very important for African farmers. Adaptation maps derived from this study can help plant breeders define ideotypes adapted to the diverse agroclimatic situations of sudano-sahelian Africa.