1. Department of Plant Sciences (Plant Breeding), University of the Free State, Bloemfontein, South Africa;
2. International Institute of Tropical Agriculture, Ibadan, Nigeria;
3. International Institute of Tropical Agriculture, Arusha, Tanzania;
4. Department of Horticultural Science, North Carolina State University, Raleigh, USA;
5. Bioversity International, Heverlee, Belgium;
6. Department of Biosystems, KU Leuven, Heverlee, Belgium