1. Department of Crops and Soil Sciences, Lilongwe University of Agriculture and Natural Resources, P.O. Box 219, Lilongwe, Malawi
2. Department of Agricultural Research Services, Chitedze Research Station, P.O. Box 128, Lilongwe, Malawi
3. Department of Human Ecology, Lilongwe University of Agriculture and Natural Resources, P.O. Box 219, Lilongwe, Malawi