ABSTRACT
One hundred seventy Capsicum spp. germplasm accessions were evaluated as potential sources of resistance to X. campestris pv. vesicatoria pepper race 6 (P6). This race has been identified recently in Ohio and overcomes all three known resistance genes in cultivated pepper. Only C. pubescens plant introduction (PI) 235047 was found to be resistant to X. campestris pv. vesicatoria P6 strains using hypersensitivity and pathogenicity tests. Further studies using PI 235047 as a differential line showed that strains classified as X. campestris pv. vesicatoria races P1 and P3 were heterogeneous in terms of virulence. Strains of X. campestris pv. vesicatoria P1 and P3 that were compatible with PI 235047 were reclassified as two new pepper races, designated X. campestris pv. vesicatoria P7 and P8, respectively. According to the new race classification, PI 235047 plants are incompatible with X. campestris pv. vesicatoria pepper races P0, P1, P3, P4, and P6, but compatible with races P2, P5, P7, and P8.
