Marker-assisted dissection of anthracnose resistance in the dry bean cultivar Morden003

The dry bean cultivar Morden003 is resistant to anthracnose races 73 and 105, the two most prevalent races in western Canada. Previous studies found that Morden003 carried markers OF10530r, SCAreoli and SAS13 that are linked to the Co-1, Co-2 and Co-4 resistance genes on chromosomes Pv01, Pv11 and Pv08, respectively. Morden003 had a reported resistance spectrum similar to three other cultivars that carry the Co-15 resistance gene. Using F2 and F2:3 populations from the reciprocal crosses of Morden003/OAC Rex, we mapped two race-specific resistance gene loci. An examination of known anthracnose resistance and other core markers showed no evidence of resistance being associated with the Co-1, Co-2, or Co-4 loci. Instead, the resistance genes were co-located in the vicinity of the Co-3 locus on Pv04. They were 2 cM apart and flanked by markers SAH181100 and BM161. The map generated in this research also showed strong linkage of the anthracnose resistance loci to markers SW12, PVctt001 and SF10, which were associated with the Co-3 and Co-10 loci by previous researchers. A weak, distant linkage of marker SB12 to the Co-3 locus was also detected.