ABSTRACT
Four methods widely used for QTL mapping are bulk segregant analysis (BSA), singlemarker analysis, interval mapping and composite interval mapping. In BSA, two bulks of DNA are prepared by pooling equal numbers of individuals from a segregating population which differ in a trait of interest (Michelmore et al. 1991). The bulks are then screened by between 300 and 500 markers. It is expected that all loci are randomized, except for the region containing the gene of interest where polymorphism between the bulks can be detected. Subsequent genotyping of individual plants in the population with polymorphic markers results in a localized linkage map (Collard et al. 2005). Most of the early QTL mapping efforts in cassava relied on this method (Akano et al. 2002; Lokko et al. 2005; Akinbo et al. 2012; Okogbenin et al. 2012).
