Abstract:
The majority of the world's cacao for chocolate manufacture is produced in West Africa. Cocoa breeding programs in West Africa need genetic markers to reduce the time needed for improving cocoa by screening seedlings for the presence of the markers rather than mature plants for the phenotypic traits (i.e., marker-assisted selection [MAS]). For MAS to be successful, the breeder must have both access to markers linked to desired traits and a convenient marker-assay system that can be performed locally. In this study, microsatellite markers that flanked disease resistance quantitative trait loci (QTL) but could not be assayed conveniently in West Africa were converted using a genome walking method into single nucleotide polymorphism (SNP) markers that could be assayed locally. The SNP and microsatellite markers were equally effective in identifying off-types in two different mapping populations of cacao. Also, SNPs cast doubt on whether all microsatellite markers are identical by descent. © 2013 Copyright USDA-ARS.