The role of GIS in the development and targeting of maize germplasm to farmers in West and Central Africa

Maize (Zea mays L) is cultivated under a broad range of climatic conditions in West and Central Africa (WCA). For the purpose of germplasm evaluation, maize researchers in the subregion loosely stratified the diverse environments into four agroecological zones based on their knowledge and experience rather than on quantitative studies involving climatic data. Recent advances in the development of digital spatial databases and geographic information systems (GIS) have provided unprecedented opportunities to use agroclimatic attributes to describe a geographical area. We used GIS to analyze long-term data collected on seven climatic variables relevant to maize production. Our objective was to refine the stratification of the region into well-defined agroecologic zones. As a test case, IITA's international maize trials databases involving 114 locations in sub-Saharan Africa were linked with the GIS-based classification of maize agroecological zones. GIS accurately separated the locations into four distinct zones; namely, midaltitude, rainforest, moist savanna, and dry savanna, respectively. The new stratification scheme provides a robust representation of the geographic distribution of the maize agroecologic zones in WCA. This stratification should greatly aid researchers in assessing research priorities and resource allocation for germplasm development, evaluation, and deployment