New Insights into the Anthracnose Resistance of Common Bean Landrace G 2333

The common bean landrace G 2333 carries a three gene pyramid for anthracnose resistance: Co-4 2 , Co-5 and Co-7. The Co-4 2 gene is well characterized but less information is available on Co-5 and Co-7. The objectives of this study were to determine if a new allele of Co-5 is present in G 2333; to characterize the spectrum of resistance condi- tioned by the Co-7 gene by deriving lines which only possess the Co-7 gene; and to test the MSU7 lines for allelism to Co-3. We propose that G 2333 carries a second allele at the Co-5 gene, different from that possessed by TU, and that the allele in G 2333 (SEL 1360) be designated Co-5 2 . With the exception of breeding line MSU7-1, the other derived MSU7 lines do not carry the Co-7 gene and are not allelic to Co-3 suggesting that G 2333 carries more than three genes for an- thracnose resistance.