Boersma, J. G., Conner, R. L., Balasubramanian, P. M., Yu, K. and Hou, A. 2013. Marker-assisted dissection of anthracnose resistance in the dry bean cultivar Morden003. Can. J. Plant Sci. 93: 1115-1123. 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 OF10_530r, 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 F_2:3 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.