RAPD MARKERS FLANKING THE ARE GENE FOR ANTHRACNOSE RESISTANCE IN COMMON BEAN

Incorporation of the dominant gene Are, of Middle American origin, int o commercial cultivars of Phaseolus vulgaris L., has been the main dis ease control strategy of plant breeders to limit the potential damage of Colletotrichum lindemuthianum (Sacc. & Magnus.) Lams.-Scrib. A rand om amplified polymorphic DNA (RAPD) marker designated 0Q4(1440) genera ted 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 centimorga ns (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 phas e RAPD marker B355(1000), generated by the 5'-GTATGGGGCT-3' primer map ped at 5.4 +/- 2.3 cM from the Are allele in the Andean genetic backgr ound 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 bracketi ng molecular markers allowed tagging of the Are allele with a selectio n fidelity of 99%. Use of the OQ4(1440) and B355(1000) RAPD markers fo r marker-based selection will afford the opportunity to retain the Are anthracnose resistance gene in bean germplasm, as other epistatic res istance genes are characterized, and incorporated into contemporary be an cultivars.