RAPD patterns for the tested wild potato S. demissum and six potato cultivars varied in their resistance to P. infestans, generated by 10-mer random primers (K9, K10, K11, K12, K13, K14, K15, K16, K17 and K18). M, DNA marker; Lr, S. tuberosum cv. Lady-Rosetta (susceptible); Sd, S. demissum (very resistant); Sp, S. tuberosum cv. Spunta (moderately resistant); Ha, S. tuberosum cv. Hanna (resistant); Di, S. tuberosum cv. Diamant (susceptible); Lo, S. tuberosum cv. Lady-Olympia (susceptible); Ca, S. tuberosum cv. Cara (resistant).