RAPD markers flanking the Are gene for anthracnose resistance in common bean

Incorporation of the dominant gene Are, of Middle American origin, into commercial cultivars of Phaseolus vulgaris L., has been the main disease control strategy of plant breeders to limit the potential damage of Colletotrichum lindemuthianum (Sacc. & Magnus.) Lams.-Scrib. A random amplified polymorphic DNA (RAPD) marker designated 0Q4(1440) generated by a 5'-AGTGCGCTGA-3' decamer primer, was found tightly linked in coupling with the Are gene. OQ4(1440) mapped at 2.0 +/- 1.4 centimorgans (cM) from the Are allele in the Andean genetic background and at 5.5 +/- 2.3 cM in the Middle American background. A second coupling phase RAPD marker B355(1000), generated by the 5'-GTATGGGGCT-3' primer mapped at 5.4 +/- 2.3 cM from the Are allele in the Andean genetic background and at 7.7 +/- 2.7 cM in the Middle American background. Based on a recombination distance of 7.0 + 1.9 cM between the two markers, OQ4(1440) and B355(1000) RAPDs appear to flank the Are gene. The bracketing molecular markers allowed tagging of the Are allele with a selection fidelity of 99%. Use of the OQ4(1440) and B355(1000) RAPD markers for marker-based selection will afford the opportunity to retain the Are anthracnose resistance gene in bean germplasm, as other epistatic resistance genes are characterized, and incorporated into contemporary bean cultivars.