Use of Molecular Markers for Doubled Haploid Technology: From Academia to Plant Breeding Companies.

Molecular markers are employed for doubled haploid (DH) technology by researchers and applied plant breeders in many crops. In the 1990s, isozymes and RFLPs were commonly used marker technologies to characterize DHs and were later replaced by PCR- based markers (e.g., RAPDs, AFLPs, ISSRs, SSRs) and today by SNPs. Markers are used for multiple purposes in DH production, that is, for the study of genes underlying haploid induction and confirming homozygous plants of gametophytic origin. Furthermore, they are tools for investigating segregation in DH populations and for mapping simple and complex traits using DHs. The deployment of DHs and markers for developing trait-linked markers are demonstrated with examples from rapeseed, wheat, and barley. Marker development for resistance to viruses derived from genetic resources and their use in, for example, pyramiding of resistance genes, are given as an example for the combination of DH-technology and marker development in research. Today, marker systems amenable to automation are frequently used in applied plant breeding. Practical examples are given from Lantmännen (LM) ( https://Lantmannen.com ) using large-scale genotyping for variety development based on SSRs and SNPs.