The random amplified polymorphic DNA (RAPD) method is based on random amplification of DNA fragments, via PCR, using short primers of arbitrary sequence. RAPD markers have been applied to construct linkage maps, to assess genetic diversity, to study taxonomic relationships, and to tag disease resistance genes in plants. RAPD markers linked to a resistance gene can be identified using bulked segregant analysis (BSA), recombinant inbred lines (RILs) or near-isogenic lines (NILs). More reliable and specific PCR-based markers known as sequence-characterized amplified region (SCAR) and allele-specific associated primer (ASAP) were developed. There are several examples of the application of these DNA marker systems in marker-assisted plant breeding.