Delivering Genetic Gain in Cassava to Smallholder Farmers in Africa

Cassava (Manihot esculenta L.) produces large, edible, starchy roots that are a source of low-cost carbohydrates for more than 300 million smallholders in Africa. These farmers account for more than half of the crop’s world output. Cassava is plagued by a plethora of production constraints including diseases which impact its productivity. Typical breeding schemes will take as much as 10 years to deliver improved varieties to farmers. This limits the rate of variety improvement and breeders’ ability to respond to new challenges. Shifting from phenotype-based to genomics-based selection holds the potential to overcome such lengthy cassava breeding cycles. NextGen Cassava as a project has been implementing and empirically testing genomic selection in 3 African countries as a means to select superior clones using genomic estimated breeding values after only two years, double the number of breeding cycles feasible per unit of time, and increase the accuracy of selection at the seedling stage. Consistent genetic gains have been recorded for major virus diseases, root dry matter and fresh root yield as we progressed over 3 generations. The technique promises to revolutionize cassava breeding for the future with the ability to select based on predictions rather than observations, breeders can achieve improved genetic gains and efficiency