Genetic Improvement of African Maize towards Drought Tolerance
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Africa supports a population of over 1 billion people with over half of them depending on maize for food andfeed either directly or indirectly. Maize in Africa is affected by many stresses, both biotic and abiotic whichsignificantly reduce yields and eventually lead to poor production. Due to the high demand for maize in theregion, different improvement strategies have been employed in an effort to improve production. These includeconventional breeding, molecular breeding, high throughput phenotyping techniques and remote sensing-basedtechniques. Conventional breeding techniques such as open pollination have been used to develop droughtavoiding maize varieties like the Kito open pollinated variety (OPV) of Tanzania and Guto OPV of Ethiopia. Acombination of conventional breeding and molecular biology techniques has led to improved breeding strategieslike the Marker Assisted Back Crossing (MABC) and Marker Assisted Recurrent Selection (MARS). Thesetechniques have been used to improve drought tolerance in existing inbred maize lines like the CML 247 andCML 176. Through genetic engineering, different genes including C4-PEPC, NPK1, betA, ZmNF-YB2, cspB,ZmPLC1 and TsVP have been cloned in maize. Transgenic maize crops expressing these genes have shownincreased tolerance to drought stress. Although there is substantial progress towards developing drought tolerantmaize, many African farmers are yet to benefit from this technology. This is due to lack of an enabling policyframework as well as a limited financial investment in biotechnology research.