Caracterização de isolados de Colletotrichum lindemuthianum em feijão comum no estado do Paraná

Abstract

Anthracnose is one of the most important diseases of common bean that is caused by the fungus Colletotrichum lindemuthianum. This pathogen is highly variable, with races occurring at different levels of virulence. Therefore, for an effective breeding program, there is a need to continuously monitor the distribution and variability of the pathogen. The study had as objective to characterize isolates collected in common bean crops in Parana State. Thirty-four isolates C. lindemuthianum were tested on a set of 12 international bean differential cultivars for anthracnose in Phaseolus vulgaris L. Anthracnose disease reactions were rated visually using a severity scale from 1 to 9. Plants with disease reaction scores between 1 and 3 were considered resistant, whereas plants that rated 4-9 were considered susceptible. Twenty-five races were identified: 2, 3, 10, 11, 15, 27, 31, 63, 64, 73, 75, 79, 81, 82, 83, 90, 91, 93, 95, 259, 283, 287, 339, 346 and 351. This was the first report of races 82, 90, 259, 283, 287, 346 and 351 in Parana State; it is worth mentioning that this is the first report of race 3, 15 and 63 in Brazil, demonstrating the high genetic variability of the pathogen and evidencing the importance of monitoring in growing regions. Race 3 presented the highest frequency of occurrence (14.7%), followed by races 2, 64, 91, 95 and 351 (5.9%). Races 64 and 73 presented compatibility reactions only with cultivars of Mesoamerican origin. By other hand, races 3, 10, 27, 31, 75, 79, 81, 82, 91, 93, 259, 283, 287, 346 and 351 showed compatibility reactions with both Andean and Mesoamerican cultivars. All Andean cultivars presented reaction of compatibility with isolates. All isolates were incompatible with PI 207262, TU, AB 136 and G 2333 cultivars.