Evaluation of eleven dwarfing apple rootstocks: preliminary results.

摘要

Golden Delicious clone B trees grafted on eleven apple clonal rootstocks, M 9 EMLA, M 26 EMLA, Burgmer 751 (Cover1), Burgmer 984 (Cover 2), T 337, T 338, T 339, Jork 9, MAC 9, Pajam 1 and Pajam 2, were tested in the field to evaluate their performance in the coastal area of central Italy (Pisa). In the spring of 1994, trees were planted on irrigated loam soil at 4.5 x 2.5 m spacing and trained as slender spindles. Phenological and vegetative observations were carried out yearly and, beginning from1996, yield was recorded. In 1997-98, trunk cross-sectional area, canopy volume, and pruning wood weight showed differences among clones allowing rootstocks to be ranked according to the following order of decreasing vigour: M 9 EMLA > T 339 = Burgmer 751 = Burgmer 984 = Pajam 1 = M 26 EMLA > T 337 = T 338 = Jork 9 > MAC 9 = Pajam 2. In 1998, M 9 EMLA was the most productive (29.6 kg/tree), followed by Burgmer 751 and Pajam 1 (26 kg/tree); MAC 9 showed the lowest production (13.7 kg/tree). Burgmer 751 and Jork 9 showed the highest yield efficiency (1.8 and 1.7 kg/cm2); in contrast to T 339 and Burgmer 984, which registered the lowest efficiency (1.2 kg/cm2). M 9 EMLA and M 26 EMLA, assumed as controls, gave a medium yield efficiency, similar to the remaining rootstocks tested. Fruit quality was assessed considering size, firmness, soluble solids (鳥rix) and russeting. The different rootstocks did not affect those parameters except the soluble solids, for which MAC 9 determined a constant level in theyears (about 15鳥), probably due to its low production increment. There were no significant differences in the most important phenological stages (bud break, time of flowering and leaf fall) among rootstocks.