OBSERVATIONS ON THE OCCURRENCE OF SWEET CHERRY DOUBLE-FRUITS IN ITALY AND SLOVENIA

During the sweet cherry (Prunus avium L.) season of spring-summer 2004, the frequency of double (twin) fruit was recorded for 53 varieties grown at three sites in Italy and one in Slovenia, measured on 4 to 5 fruiting branches chosen on 5 to 10 representative trees for each variety.
Since there is an influence, during flowering bud differentiation, of temperatures above 30°C on the occurrence of double cherries, for each site the daily maximum temperature from May to July of the previous year (2003) was determined.
Data collection also included fruiting branch age and exposure, tree age and rootstock and harvest precocity of each variety.
Results showed a significant influence of genotype because at the same location, varieties with either a high percentage of double cherries or with no double fruits were found.
Fruiting branch age and exposure were not significant for the occurrence of double fruits.
Nevertheless, in all localities, the percentage of double cherries was higher for earlier-ripening varieties than for later ones.
Moreover, the occurrence of twin cherries was, generally speaking, higher at the sites for which the spring-summer sum of daily maximum temperatures during the previous year were highest, indicating the hottest sites.

V International Cherry Symposium

A. Roversi, A. Monteforte, D. Panelli, L. Folini, N. Fajt

Prunus avium, bud differentiation, daily maximum temperature, harvest earliness, fruiting branch exposure, bearing branch age

https://doi.org/10.17660/ActaHortic.2008.795.137