Andrew Kachiwile
Crop Science, Sokoine University of Agriculture
October, 2014


Drought tolerance is an increasingly important trait in cassava due to globally dwindling water resources, a shift in production areas and increasing input costs. This study was conducted to evaluate eighteen cassava genotypes for drought tolerance to counteract frequent shortages of rainfall. An experiment was set in Dodoma, Tanzania which is a drought-stricken environment where cassava genotypes were grown under-watered and water stressed conditions. Identification of drought-tolerant genotypes that also had good yield potential was facilitated by the stress treatments used on the farm. Morphological (leaf length, leaf width, plant height), physiological (leaf retention, chlorophyll content), biochemical (Catalase and Peroxidase enzymes activities) and yield (number of roots per plant, yield in tons per hectare, above-ground biomass, percentage dry matter content and harvest index) attributes were used to assess tolerance of the tested genotypes to drought stress. During harvesting, on-farm farmers participatory evaluation and organoleptic test were also conducted to enable farmers to select the best genotypes based on consumers criteria. It was found during the study that water stress had a profound effect on growth, physio-chemical and yield performance of cassava genotypes. All attributes measured were significantly influenced by drought except leaf length at180 DAP, plant height at 120 and 150 DAP, number of roots per plant, the weight of above-ground biomass and harvest index (P≤0.05). Generally, water stress suppressed both growth and yield of the crop. Through the study, superior drought promising cassava genotypes identified were 92B/00073, KBH 2006/363, KBH 2006/12 and KBH 2006/18. These genotypes performed well under stress and well-watered conditions and thus may serve as parents for drought stress improvement and genetic analysis.