Mi.P.A.F. targeted project for evaluation of European and Japanese plum rootstocks in Italy: Results of six years of observations

The Mi.P.A.F. (Italian Ministry of Agriculture) targeted project "National Lists of Recommended Rootstocks and Cultivars", coordinated by Prof. F. Loreti, University of Pisa, aims at evaluating the performance of fruit rootstocks introduced into the Italian nursery market. As part of this project, trials were established to compare some of the most interesting rootstocks for European and Japanese plum in 9 different locations in Italy. The rootstocks tested were: 'Citation-Zaipime', 'GF 31', 'Marianna GF 8/1', 'Ishtara-Ferciana', 'Jaspi-Fereley', 'Julior-Ferdor', 'Myrobalan 29C', 'Myrobalan B', 'MrS 2/5' and 'Myrocal'. In 1995, nine orchards were planted at 5 × 5 m spacing; in each orchard, 15 trees per rootstock, grafted either with 'Stanley' European plum (EP) or 'Ozark Premier' Japanese plum (JP), and trained to open vase, were randomly distributed in blocks of single tree plots. Locations of the orchards were distributed throughout Italy: two in the North (Cuneo and Forlì), two in the centre (Pisa and Ancona) and five in the South of the peninsula (Caserta, Metaponto, Catanzaro, Palermo and Cagliari). This report highlights the main results obtained after 6 years of growth (3 years of production). Data are summarized either per rootstocks or per location. Both for JP and EP, 'Myrobalan 29C' and 'B', 'Marianna GF 8/1', 'Julior® -Ferdor'and 'Jaspi® -Fereley' showed the best adaptability to the pedo-climatic conditions of the different experimental locations; all by sustaining a quite balanced plant growth and production. 'Ishtara® -Ferciana' showed a better capacity to control plant vigour and to increase fruit size. 'Citation® Zaipime', 'GF 31' and 'MrS 2/5' exhibited the lowest aptitude to the Italian plum production system, although there were some exceptions related to particular locations