1. Ladoke Akintola University of Technology, Ogbomoso, Nigeria
2. International Institute of Tropical Agriculture (IITA), Oyo Road, PMB 5320, Ibadan, Nigeria
3. West Africa Centre for Crop Improvement (WACCI), University of Ghana, Legon
4. Department of Crop and Soil Science, College of Agricultural Sciences, Oregon State University, Corvallis, OR 97331