Some thoughts on how to use markers in tetraploid rose breeding

Thanks to recent advances in high-throughput genotyping tools and software for genetic analyses, it is now possible to perform QTL mapping and genome-wide association analysis in tetraploid roses and to establish the effect of favorable SNP marker haplotype(s) (“plus-alleles”). The challenge is how to use these tools and technologies for rose breeding in a cost-effective way. At least four points need to be addressed: (1) which steps of the breeding process may benefit from marker information; (2) what is the value of the identified plus-alleles for the trait; (3) where in the breeding germplasm do these plus-alleles occur, and (4) how can plants carrying these plus-alleles be selected efficiently. Here we discuss for which purposes markers may be applied.