Enhanced understanding of anthracnose resistance in Michigan Dark Red Kidney common bean cultivar

Anthracnose, caused by the fungus Colletotrichum lindemuthianum (Sacc. and Magnus) Briosi and Cavara, is a major disease affecting the common bean (Phaseolus vulgaris L.), potentially causing yield losses of up to 100%. Utilizing resistant cultivars is the most effective approach for disease control. This study aimed to characterize the genetic resistance of two cultivars, TU and Michigan Dark Red Kidney (MDRK), to anthracnose. Inheritance tests were performed on F2:3 families from the TU (R) × AND 277 (S) cross using C. lindemuthianum race 3, and on F2:3 families from the crosses TU (R) × Kaboon (S) and TU (R) × Perry Marrow (S) inoculated with race 39. Inoculation with three races of C. lindemuthianum showed that MDRK carried the allele of the Co-1 locus. However, inoculation of F2:3 families from the MDRK × TU cross with race 1545 revealed that MDRK's resistance to this race is conditioned by two dominant genes (Co-1 allele on Pv01 and another allele on Pv04). Segregation results from inheritance tests using F2:3 families with the TU resistant cultivar fitted to a 1RR:2RS:1SS ratio, indicating the presence of a single dominant gene in the TU cultivar. Both the Mesoamerican TU and the Andean MDRK cultivars represent valuable sources of resistance to C. lindemuthianum and can be incorporated into common bean breeding programs to enhance disease resistance.