Molecular markers

Clearly identifiable, short DNA segments with known positions in the genome

Molecular markers are used in plant breeding to identify plants with desirable traits (marker-assisted selection), thereby speeding up the breeding process.

Using molecular markers it is possible to follow what happens to genes in a breeding cycle, even when the gene sequence is not known. Researchers just need to know which marker is coupled to which trait. To find this out, researchers have to conduct elaborate tests on cross-bred progeny. If the same allele of a particular marker is always detected in plants with a certain trait, it means that the relevant gene will be found close to this marker. Since the markers are at fixed locations in the genome, they serve as a guide for locating particular traits.

Data about such links is entered on the gene maps that now exist for almost all the major crop types. The use of molecular markers is already widespread in resistance breeding in particular.

As well as being used for the selection of desirable traits, molecular markers are also used e.g. to identify varieties and to trace plant relationships and lineage.