Abstract
Five cultivars [Abador, Ceras, Mars, Mini and Spring] of peas are differentially susceptible to 3 races of P. syringae pv. pisi. Within a given cultivar, the host-pathogen combination in which resistance was expressed in seedling assays resulted in high level of pisatin and yellow-green pigmentation in epidermal cells in endocarp tissue. These responses were either absent or lower in susceptibe interactions. Pisatin at 68 .mu.g/ml was inhibitory to in vitro growth of all 3 races of P. syringae pv. pisi.