Evaluation of Chinese Cabbage Cultivars from Japan and the People's Republic of China for Resistance to Turnip Mosaic Virus and Cauliflower Mosaic Virus1

Abstract In greenhouse and field tests, 46 accessions of Chinese cabbage ( Brassica campestris L. ssp. pekinensis (Lour.) Olsson), recently introduced from Japan and the People's Republic of China (PRC), were evaluated for resistance to 3 major strains of turnip mosaic virus (TuMV-Cl, TuMV-C2, and TuMV-C3) and one of cauliflower mosaic virus (CaMV-1). Immunity and/or resistance to the TuMV strains was found among Chinese plant introductions (PI), whereas in Japanese cultivars sources of immunity or resistance were confined to the strains TuMV-C1 and TuMV-C2. None of the 46 cultivars was resistant to CaMV-1. PI 391560(1), PI 418957, PI 418959, and PI 419069 from the PRC were immune or resistant to each of the 3 strains of TuMV, representing valuable germplasm material for intra- and interspecific gene transfer. In early fall of 1979, an isolate of TuMV was recovered from a systemically infected plant of PI 391560(1). Although uncommon, resistance to this newly recognized strain (TuMV-C4) was found in plants of PI 418957. Strain specificity must be considered in developing TuMV-resistant cultivars, since their performance will depend upon the presence and distribution of the virus strains in a given locality.