ABSTRACT
Cassava breeding through phenotypic recurrent selection is a lengthy process, owing to its 12-month cropping cycle and the low clonal multiplication rate of about 5-10 clones/ generation for every parent clone propagated. A breeding cycle takes five to six years to obtain enough planting material to conduct replicated trials across multiple locations (Kawano 2003). Although there are several tools and methods to increase multiplication rate, these are typically not practical for application to the large number of genotypes managed in a breeding programme. Moreover, cassava field plots require relatively large spacing between plants, which limits breeders’ ability to adequately phenotype large numbers of entries during early stages of the selection cycle. By reducing the number of seedlings using marker-assisted selection (MAS), field breeders can allocate their limited phenotyping resources to a smaller number of selection candidates for further phenotypic evaluation of complex traits such as yield and drought tolerance.
