Title: Abstracts of presentations at the XXVI Congress of the Italian Phytopathological Society (SIPaV)
Abstract: The aim of this work was to evaluate the response of various species and provenances of Juglans to the anthracnose agent Gnomonia leptostyla.The research was carried out in the 15-year-old experimental plantation Cesurni Farm (CRA) near Tivoli, Rome, during the 2014 vegetative seasons, characterized by a high anthracnose incidence.The considered material consisted of four Juglans species originated from USA, i.e.J. cinerea (8 genotypes), J. microcarpa (18), J. sieboldiana (16) and J. nigra (66) and of J. regia plants of different provenances, from France (27), Russia (16), Israel (28), Iran (9), northern Italy (32), central Italy (36), southern Italy (42).Both the average number of necrosis spots and the percentage of leaf necrotic area were useful tools to evaluate disease susceptibility.J. cinerea and J. sieboldiana showed only small (2-4 mm diameter) necrotic spots, while the other species exhibited necroses larger than 1 cm 2 , with stronger severity (in descending order) on J. regia, J. nigra and J. microcarpa and, among J. regia, for the provenances from France, Russia, Italy, Israel and Iran.J. cinerea, J. sieboldiana, J. microcarpa, J. nigra, resulted more resistant to anthracnose than J. regia.Among J. regia, the genotypes of French origin were discreetly resistant, those from Russia and Israel were tendentially susceptible, those from Iran were very susceptible, whereas the genotypes from Italy ranged from very susceptible to moderately resistant.These results represent an important starting point for the selection and genetic improvement of walnut for fruit and wood production.