Evaluation of Italian Clones of Artichoke for Resistance to Verticillium dahliae . M. CIRULLI, Department of Plant Pathology, University of Ban, Via G. Amendola 165/A, 70126 Bari, Italy . F. CICCARESE, and M. AMENDUNI, Department of Plant Pathology, University of Ban, Via G. Amendola 165/A, 70126 Bari, Italy. Plant Dis. 78:680-682. Accepted for publication 20 December 1993. Copyright 1994 The American Phytopathological Society. DOI: 10.1094/PD-78-0680.

Selected clones of artichokes were tested over 3 yr of perennial cropping to assess their resistance to Verticillium wilt. The disease severity was evaluated on the basis of external symptoms (ES) and vascular discoloration (VS). There were no artichoke clones which showed complete resistance, but based on disease incidence and severity indices, the clones could be grouped into susceptible, moderately resistant, and resistant classes. The most resistant clone, 76, had only 19.8 and 19.2% of plants showing VS and ES, respectively, and 9.2 and 10.3% severity indices for VS and ES, respectively. By comparison, clone 125, a susceptible check, had 100 and 97.5% of plants affected by VS and ES, respectively, with 79 and 78.7% severity indices for VS and ES, respectively. In general, the correlation coefficient between VS and ES was high. However, some resistant clones showed a disproportionately higher percentage of VS over ES, indicating that resistant clones may contain different forms of resistance, and that appraisal of both VS and ES is necessary to avoid over- or underestimating Verticillium resistance in artichoke germ plasm.

Keyword(s): Cynara scolymus L., partial resistance