1. Faculty of Agronomy and Environmental Science, Université DanDicko Dankoulodo de Maradi, Maradi, Niger
2. International Institute of Tropical Agriculture, Dryland Cereals, Niamey, Niger
3. Present address: International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), West and Central Africa Research Program, Niamey, Niger
4. Institut National de Recherches Agronomiques du Niger (INRAN), Maradi, Niger
5. Institut de l’Environnement et de Recherches Agricoles (INERA), Kamboinse, Burkina Faso