Marker‐Assisted Crop Breeding

Abstract

Molecular genetic markers are tools that provide an opportunity to assist crop breeders in the development of new cultivars. They can be used as a proxy for costly or difficult‐to‐phenotype traits, enabling the screening of germplasm in a more efficient and robust way. The approach of using molecular markers in breeding programs is not new, and the key aim when developing such markers is to identify loci that are in linkage disequilibrium with the trait of interest. However, interesting developments in the technology underpinning contemporary crop genetics, such as next‐generation sequencing and high‐density genotyping platforms, can be translated and applied to crop breeding, potentially improving this process. Key Concepts Genetic loci in linkage disequilibrium with a trait of interest can be used to design molecular markers for breeding. Large numbers of single‐nucleotide polymorphisms (SNPs) enable marker discovery when mapping the trait, with coverage of around one marker per 2 cM to map a trait for marker‐assisted selection (MAS) in crops. A much smaller number can be used for tracking preferred alleles during the breeding process. A denser set of markers than those used in MAS would be needed for genomic selection.