The identification of a cleaved amplified polymorphic sequence (CAPS) marker for the flax rust resistance gene M-3

A cleaved amplified polymorphic sequence (CAPS) marker has been developed f or the flax rust resistance gene M-3. This molecular marker was identified in a rust differential for M-3 by screening primer sets, whose sequences we re based on the nucleotide sequence of the M gene. One primer set was ident ified that co-amplified, along with other related sequences, a 2.9-kb DNA s egment of M-3 or an M-like gene tightly linked to the M-3 locus. Restrictio n fragment analysis revealed several unique DNA fragments that were linked to the presence of the M-3 gene in a F-2 segregating population. This molec ular marker along with recently developed markers for the L-2, L-6, L-9, an d L-11 alleles will be useful for marker-assisted selection in breeding pro grams for obtaining multigenic resistance against flax rust in Canadian fla x cultivars.