RESEARCH ON POME FRUIT ALTERATIONS REFERABLE TO VIRUS INFECTIONS

Transmission trials by double grafting, using Golden Delicious (GD), Belle de Boskoop (BB) and Cox’s Orange Pippin (CX) scions as indicators were carried out in 1974. GD trees detected in two different fruit areas showing apple rough skin (ARS) or apple russet ring (ARR) symptoms, Renette of Canada trees with ARR-type symptoms, as well as GD, BB, Red Gravenstein (RG) and Lord Lambourne (LL) budwood from scions that in 1969 had been topgrafted on a ten-year-old Golden Delicious tree showing ARS or ARR or ARW-type symptoms on all fruits were chosen as sources of inoculum.
Fruit reactions of the four topgrafted scions had been differentiated, both as frequency and type of symptoms.

Field surveys have been carried out in orchards of the two fruit areas, in order to check variability in symptom displaying in different years.

Results acquired have proved that the reactions induced on the indicators may be different in respect to the syndrome exhibited by the donor trees.
Both percentage of altered fruits and symptoms intensity appear influenced by inner factors of the tree, connected with graft combination, as well as by environmental conditions.
Constancy in type of symptoms, resulted to be higher in the older trees of the orchards, where crop is also more stabilized.

XII International Symposium on Fruit Tree Virus Diseases

E. Refatti, R. Osler

https://doi.org/10.17660/ActaHortic.1983.130.35