Farmers' Agronomic and Social Evaluation of the Productivity, Yield and Cooking Quality of Four Cassava Varieties

The study evaluated the productivity, yield and cooking quality of four cassava varieties grown on poor soils at Beposo in Wenchi Municipality in the forest/savannah transitional zone of Ghana, between October 2008 and October 2009. The trial included two local varieties selected by the farmers and 2 improved varieties developed by the national agricultural research system, and three fertilizer treatments. The fertilizer treatments were 4 t ha-1 poultry manure, 32-32-32 kg N-P2O5-K2O ha-1 and unfertilized controls. Mean fresh root yield of the four cassava varieties ranged from 8.9 t ha-1 (Afosa) to 30.6 t ha-1 (Bensre). Application of the mineral fertilizer resulted in between 140% and 300% increase in fresh root yield for the improved varieties and between 43% and 63% for the local varieties while application of poultry manure resulted in yield increase of between 86% and 124% for the improved varieties and about 48% for the local varieties. Fertilization significantly improved the mealiness in all the varieties with the local varieties being the mealiest. Farmers’ criteria when selecting a variety for planting included yield, mealiness and maturity. Farmers’ most preferred cassava variety was the local variety Bensre; the least preferred variety was the improved variety, Essam. Although the local varieties were less responsive to fertilization, they appeared to be well-adapted to local conditions and had preferred root quality attributes. These traits can be used for improving root quality and productivity in cassava breeding. Mealiness of cassava roots could also be improved on poor soils through fertilization