Pearl millet (Pennisetum glaucum) and sorghum (Sorghum bicolor) are the main staple food crops grown by smallholder farmers in marginal agricultural environments in the semi-arid to arid regions of West Africa. They are critical food security crops because some of the world’s poorest and most food-insecure people depend on them. Food shortages occur every year in this region and only increased agricultural productivity offers people hope for better, more productive lives.Pearl millet and sorghum yields in the region are low, rarely more than 1000 kg/ha and often quite less. Inadequate and/or erratic rainfall, poor soil fertility, and high temperatures are among the regions’ major production constraints. Earlier breeding efforts aimed at improving the productivity of these two crops have resulted in very limited success. The diversity of production environments and large year to year variation in climatic conditions worked against a strategy that targeted varieties for wide adaptation across the region. Similarly, the green revolution approach of developing photoperiod insensitive, potentially high yielding varieties with a high harvest index has been found to be equally inappropriate as a result of their lack of adaptation to low input conditions and their generally poor tolerance to the multitude of biotic and abiotic stresses that are common in farmers’ fields.This project is designed to develop in a regionally coordinated, farmer-participatory manner pearl millet and sorghum populations or cultivars with specific adaptation to different production environments in Niger, Mali, and Burkina Faso. It consists of two sub-projects dealing with specific targets: (1) Dynamic genepool management and farmer-participatory recurrent population improvement of sorghum and pearl millet; and (2) development of improved sorghum cultivars with high phosphorus (P) efficiency and adaptation to low soil fertility using innovative screening, hereafter abbreviated as “P efficiency in sorghum”.The dynamic genepool management and farmer-participatory improvement aims at a simultaneous in situ conservation and improvement of plant genetic resources to meet farmer’s needs and the challenges of adaptation to climatic variability and site-specific conditions. The varietal diversity available within each major agro-ecological zones across West Africa will be used to provide farmers with a broader range of options in the form of new broad-based populations. Diverse base populations will be built through crossing and recombining genetically and/or geographically diverse genetic materials selected by farmers and breeders. Representative seed lots of targeted base-populations will be distributed to farmers in contrasting sites of a target region. Natural and recurrent selection by farmers and breeders will act on the distributed material and lead to the development of new subpopulations that can be excellent sources of variation for specific adaptation, farmer-preferred traits, and also new trait combinations (via recombination) not previously available. The sum of all subpopulations grown in the contrasting sites can be considered as “mass reservoir of genetic adaptability.”. This gene-pool approach provides the best opportunity to “offer a wide diversity of material to the wide diversity of farmers” for effective participatory plant breeding.P efficiency in sorghum aims at development of cultivars for adaptation and productivity under poor soil conditions where phosphorus is usually a limiting factor. Current alternatives for P fertilization are either not accessible to small farmers or as with rock phosphate they do not show significant effects on crop productivity. This subproject involves multidisciplinary research at the NARS in Niger and Mali, and a CG center (ICRISAT Mali), all working with local farmers. Landrace cultivars and breeding lines will be evaluated in the field for performance under variable P conditions and in laboratory experiments for Al-tolerance, another constraint for nutrient uptake in cereals. Selected lines will be also tested for P uptake using local rock phosphate and for adaptation to intercropping/rotation with legumes, common farmer practices in West Africa which may enhance P uptake. This work will benefit from long-term experience of the Maize and Sorghum Research Center of the Brazilian Corporation for Agricultural Research (Embrapa MS) in research on enhancing P-uptake and tolerance to high Aluminium concentrations in sorghum. It is expected that the dynamics of these collaborations will lead to successful identification and release of sorghum lines adapted to prevailing cultural practices. Such cultivars may be highly productive through their better use of the natural resource of rock phosphate, and intercropping with leguminous crops on poor sandy soils.The resulting increased availability, accessibility, cultivation, and stakeholder’s training in the management of specifically adapted pearl millet and sorghum genetic resources will contribute to long-term food security in the region.