In vitro evaluation of resistance of potato cultivars to Phytophthora infestans

The resistance of ten potato cultivars (Agria, Ajar, Desiree, Liseta, Kenne bec, Majestic, Monalisa, Prima, Spunta and Tonda di Berlino) to Phytophthor a infestans was analyzed in vitro using 8 fungal strains. An assay based on electrolyte leakage was used for screening leaves and tuber tissues with f ungal culture filtrates. With almost all cultivars the resistance of leaves did not correlate with the resistance of tubers. Cv. Ajar appeared the lea st susceptible in both leaf and tuber tests, while the cv. Prima was the mo st susceptible in tuber tests.