Development of SCAR markers linked to a Phytophthora fragariae resistance gene and their assessment in European and North American strawberry genotypes

Two dominant sequence characterized amplified region (SCAR) markers (linked at 3.0 cM, coupling phase) mere constructed for the strawberry (Fragaria x ananassa ouch,) gene Rpf1. This gene confers resistance to red stele root rot, caused by the soil-horn fungus Phytophthora fragariae Hickman var, fra gariae, The SCAR markers were developed originally from the sequence of RAP D OPO-16C((438)) that is Linked in repulsion phase to the Rpf1 allele, This SCAR primer set produced multiple bands in the resistant test progeny and in some of the susceptible progeny; therefore, new SCARs were developed bas ed on the sequence differences among these bands. These new SCARs were link ed in coupling phase to the Rpf allele and mapped to the same location as t he original RAPD OPO-16C((438)). The SCAR markers, as well as some addition al RAPD markers known to be linked to Rpf1, were shown to be highly conserv ed in linkage to the gene based on examination of 133 European and North Am erican Fragaria L, sp, cultivars and breeding selections. These flanking RA PD and SCAR-PCR markers can be used in breeding programs for the selection of red stele (Rpf1) resistance.