Evaluation location: Minnesota, United States
From 1990-1994 the USDA Plant Introduction Pea collection were evaluated under controlled conditions for resistance to an aggressive strain of Aphanomyces euteiches. This strain (Ae 467) was isolated from pea in Wisconsin, and from of its pathogenicity characteristic have been reported(Plant Disease 75:1153-1156). Fort-four seeds of each accession were surface disinfested, and 22 seeds were sown individually in cavities of two separate plastic multi-cavity trays containing vermiculite. One tray served as a control and only water was applied to it. Seven days after sowing each seedling in the other replicate tray was inoculated by injecting 4 ml of a zoospore suspension containing 100 zoospores/ml around its roots. Disease severity index and percent loss of root and vine biomass due to disease were determined for each set of 20 plants 12 days after inoculation.