Objective: to determine the reaction of 53 lines and three varieties of black bean (Phaseolus vulgaris L.) to inoculation with Uromyces appendiculatus and Colletotrichum lindemuthianum, to identify genotypes resistant to rust and anthracnose.
Design/methodology/approach: 10 seedlings of each genotype were inoculated in the greenhouse with a suspension of U. appendiculatus uredospores and another 10 with a suspension of C. lindemuthianum conidia. At 14 days after inoculation, the reaction of the genotypes to rust was evaluated with a severity scale of 1 to 6, and to anthracnose, with a
scale of 0 to 4. The data were analyzed in a completely randomized design with 10 replications per treatment and LSD at 0.05 was applied for the separation of averages.
Results: 41 genotypes showed a hypersensitivity reaction to rust, of which 25 had a reaction value of 2.0, statistically lower than those of controls. In turn, 45 genotypes were resistant to anthracnose, of which 18 had a value of 1.0, statistically similar to that of Negro Jamapa and lower than those of the rest of the genotypes.
Study limitations/implications: due to the diversity of races of both pathogens, the genotypes were inoculated with monopustular isolates of the principal races of U. appendiculatus and with monosporic cultures of C. lindemuthianum, which occur in the bean crops of Veracruz and Chiapas.
Findings/conclusions: 25 lines resistant to rust and 18 to anthracnose were identified, which stood out for presenting the least damage from these diseases.