Field evaluation of old Italian apple cultivars for scab susceptibility

Scab resistance is one of the main targets in apple breeding. Plants with low susceptibility to this disease are checked to introduce in biological or integrated fruit growing systems or as a source of durable resistance in breeding programs. The local or ancient apple germplasm offers good examples of tolerance and adaptation to biotic and abiotic stresses. For this reason, fifty old Italian apple cultivars from Central Italy were observed for three years in a collection at the experimental farm of Tuscia University . Cultivars Golden Delicious, Ozark Gold and the scab resistant Florina were considered as control. The plants, grafted on M26 rootstock, were not sprinkled with fungicides during the experiment. The symptoms on samples of 100 leaves per plant and on all the fruits were periodically checked during the growing season and classified on the basis of their intensity and diffusion; the incidence of the disease was then calculated. The difference among cultivars was relevant. While the test cultivars, with the exception of Florina, showed susceptibility to scab, with high incidence both at fruit and leaf level, some of the old cultivars (Agostina, Fragola, Musella, Rosa Romana, Agre, Paradisa) did not show any symptom on the leaves or only slight attack were detected during the three years. Only two cultivars, Fragola and Musella, fruits were not affected by the disease. Many cultivars showed few symptoms and low incidence of disease (Rosa Romana, Rosa, Rosetta, S. Agostino)