Evaluation of parsley (Petroselinum crispum) for resistance to the pathogens Alternaria radicina, Erysiphe heraclei, Fusarium oxysporum, and celery mosaic virus (CeMV)

Resistance tests of 127 parsley accessions (Petroselinum crispum) were carried out during 2 years of field investigations involving natural infection for black leaf spot (Alternaria radicina), mildew (Erysiphe heraclei), leaf chlorosis (Fusarium oxysporum) and viruses, particularly celery mosaic virus (CeMV). In this first extensive evaluation of parsley for all tested pathogens accessions were found to be free of symptoms. Varieties of vars. crispum and tuberosum contained more accessions weakly infected or immune to black leaf spot than vars. vulgare and neapolitanicum. In a separate test five var. crispum accessions showed significantly reduced disease ratings, indicating their potential as sources of resistance. Mildew attacked almost the same number of accessions in both years: 29 accessions of var. crispum showed no symptoms, but 16 of the var. tuberosum accessions were highly susceptible. Whereas in the var. vulgare one half of the introductions were moderately or strongly infected by viruses, mainly CeMV, a high number of plants remained uninfected in the vars. crispum, neapolitanicum and tuberosum. In the case of F. oxysporum, the greatest amount of infection was in the var. crispum during both years. The sources of resistance described including multiple resistance would be of interest in future breeding programmes for resistance to the parsley pathogens discussed.