Rice Genetic Improvement for Abiotic Stress Tolerance in Africa

144 (eds M.C.S. Wopereis et al.) Crop and water management can be improved through efficient irrigation schemes, better infrastructure and hydrological control, and optimal use of fertilizers, which can alleviate some of the effects of abiotic stresses. These measures are effective in reducing yield losses, and most improved varieties are responsive to such measures, consequently stabilizing productivity and narrowing yield gaps (Ismail et al., 2008). However, the costs of adopting these measures are prohibitive for most resource-poor African farmers and local governments. Alternatively, developing rice germplasm tolerant to the prevalent stresses involves no additional costs to farmers and can enhance and stabilize productivity considerably (Ismail and Tuong, 2009). Hence, varietal improvement should be given priority as an entry point for increasing and stabilizing rice production in sub-Saharan Africa. As much as possible, this should be combined with improved management practices to realize the full yield potential of the new tolerant varieties developed. This is all the more important given that the potential impact of research targeted to reduce yield loss due to stresses was estimated at a global cumulative benefit of US$ 32.9 million for seven countries over 3 years (AfricaRice, 2011b). This means Introduction