PERFORMANCE OF NEW AND STANDARD CHERRY ROOTSTOCKS IN DIFFERENT SOILS AND CLIMATIC CONDITIONS

Within the framework of a National program supported by the Italian Ministry for Agricultural and Forestry Policy, three different sweet cherry rootstock trials were established in the north (Forlì), center (Rome) and south (Catanzaro) of Italy. The Forli and Catanzaro trials (planted spring 1993) consisted of ‘Lapins’ grafted on: Mazzard F12/1, Mazzard F12/1-1M (induced mutation of F12/1), Franc 4, Mont x Rom (all selections of P. avium); SL 64, Magyar (both selections of P. mahaleb); CAB 6P, CAB 11E, Tabel^® Edabriz, Vladimir, Victor (all selections of P. cerasus); CxA (P. avium x P. cerasus); (MaxMa Delbard^®14 (P. avium x P. mahaleb); Colt (P. avium x P. pseudocerasus); GM 9 (P. incisa x P. serrulata); GM 61/1 (P. dawyckensis), GM 79 (P. canescens), Gisela^® 5 (P. cerasus Schattenmorelle x P. canescens), and Gisela^® 10 (P. fruticosa x P. avium). The Rome trial (planted spring 1997) consisted of ‘Lapins’ on: Mazzard F12/1, Mazzard seedling (all P. avium); SL 64, Argot (all P. mahaleb); CAB 6P, CAB 11E, Edabriz, Weiroot 158, (all selections of P. cerasus); Colt, MaxMa Delbard^®14 and MaxMa Delbard^®97 (P. avium x P. mahaleb); GM 61/1; GM 79; and Gisela^® 5.
Rootstocks that promoted the most vigor were those that originated from P. mahaleb, followed by Colt, F12/1, CAB 6P and Victor. Mazzard F12/1 and Mont x Rom (P. avium selections) were intermediate in growth and yield, generally less than Colt. Magyar, SL 64, Colt, CAB 6P and Victor had the highest production, but only Victor combined very high yield efficiency in both trials. The weakest rootstocks were Gisela^® 5 and GM 9, which induced poor tree growth and high mortality. Gisela^® 10, GM 61/1, GM 79 and Tabel^® Edabriz induced low vigor, but seemed to be affected negatively by physiological stress induced by the hot climatic conditions of southern Italy. A high number of suckers was observed with Vladimir, CAB 6P and CAB 11E, while fewer suckers were seen with Victor and MaxMa Delbard^®14. The best fruit size was obtained with P. mahaleb selections in the south and with P. avium and P. cerasus selections in the north. Gisela^® 5, Gisela^® 10, Tabel^® Edabriz and GM 61/1 had significantly lower fruit weights. While it is too early to report many definitive conclusions from the trial near Rome, trees on Weiroot 158 have been most precocious, with significantly higher production and yield efficiency compared to the other rootstocks. Preliminary data show the highest vigor with Colt and Argot, followed by MaxMa Delbard^®14, CAB 11E, and CAB 6P. As elsewhere, trees on Gi 5 were very weak.