Submitted to: National Soybean Rust Symposium
Publication Type: Abstract Only
Publication Acceptance Date: December 30, 2006
Publication Date: December 30, 2006
Citation: Pastor Corrales, M.A., Miles, M., Hartman, G.L., Frederick, R.D. 2006. Reaction of common bean cultivars to different isolates of the Asian soybean rust pathogen, Phakopsora pachyrhizi. National Soybean Rust Symposium. 45.
We evaluated the reaction of 16 selected common bean cultivars with different genes for resistance to Uromyces appendiculatus to several isolates of Phakopsora pachyrhizi and compared their reactions with those of the soybean accessions that were the sources of the known single resistance genes to P. pachyrhizi. We also wanted to detect any potential sources of resistance to P pachyrhizi within the common bean cultivars and to determine if there is a differential response among the common bean cultivars. The common beans evaluated in this study appeared to have resistance to soybean rust, but none were immune. When inoculated with each of six P. pachyrhizi isolates, cultivars, CNC, PI 181996, Aurora, and Pinto 114 were the most resistant to all six isolates, with lower severity, less sporulation and consistent RB lesions associated with resistance in soybean. A differential response was observed with a cultivar by isolate interaction among the common bean cultivars when inoculated with the isolates of P. pachyrhizi for both severity and sporulation levels. Among the common bean cultivars the presence of the known Ur genes for resistance to U. appendiculatus, singly or in combination, did not correspond with the reaction of these cultivars to P. pachyrhizi suggesting that resistance in common beans to P. pachyrhizi must be derived independently from the Ur genes that confer resistance to U. appendiculatus. The common bean cultivars evaluated in this study were all more resistant than the moderately susceptible soybean ‘Ina’ and the threat of soybean rust, caused by P. pachyrhizi, does not appear to be as severe in common bean production as it is with soybean production.