Common bean (Phaseolus vulgaris) rust, incited by Uromyces appendiculatus, is among the most important diseases affecting this culture. Several works have demonstrated the extensive pathogenic variability of U. appendiculatus in Brazil. However, the use of distinct sets of differential cultivars prevents the comparison among the data obtained and the identification of sources with ample resistance spectra. The objectives of this work were: 1) to characterize seven U. appendiculatus isolates collected in different regions of the state of Minas Gerais in relation to the 19 rust differential cultivars defined in the "The Bean Rust Workshop" in 1983, in Porto Rico, and 2) to compare the resistance/susceptibility patterns obtained with those reported with isolates collected in Santa Catarina, Rio Grande do Sul and Goiás, to identify sources with ample resistance spectra. The seven isolates collected in the state of Minas Gerais were classified as seven different pathotypes. The differential cultivars with the largest resistance spectra were 'Redlands Pioneer', 'California Small White 643', 'Brown Beauty', 'AxS 37' and 'Compuesto Negro Chimaltenango'. Despite the fact that the cultivars California Small White 643, AxS 37 and Brown Beauty have been excluded from the new differential series proposed in 2002, in South Africa, we strongly recommend that these three cultivars should also be characterized in future studies in Brazil as a mean of monitoring the pathogenic variability of U. apppendiculatus populations in bean growing regions.
Phaseolus vulgaris; common bean rust; sources of resistance
