1. CIRDES, USPAE, Bobo-Dioulasso, Burkina Faso
2. CIRAD, UMR SELMET, Bobo-Dioulasso, Burkina Faso
3. SELMET, Univ Montpellier, CIRAD, INRAE, Institut Agro, Montpellier, France
4. CIRAD, UPR AIDA, F-34398 Montpellier, France
5. AIDA, Univ Montpellier, CIRAD, Montpellier, France
6. CIRAD, UMR SELMET, F-34398 Montpellier, France