Efficacy of using Rain Protective Plastic Films against Cracking of Four Sweet Cherry (Prunus avium L.) Cultivars in Greece

Cherry cracking due to rain is the major problem for cherry cultivation. Several methods have been proposed for alleviating this problem, including the use of rain protective coverings. The aim of this research was to study the effect of rain protective covering on fruit cracking, fruit quality and photosynthetic parameters of four sweet cherry cultivars. The experiments were conducted during three successive years. Half of a commercial cherry orchard was covered by high density polyethylene plastics, whereas the other half remained uncovered (control). The results showed that the covering had no affect on the productivity and mean fruit weight in all cultivars, except for ‘Early Lory’ which had higher values in 2009. The cracking percentage of all cultivars was significantly lower in covered trees than the controls, resulting in a positive tendency on marketable yield. In 2010, total antioxidant activity was higher in the covered fruits of ‘Ferrovia’, ‘Early Star’ and ‘Van’ compared to the control, whereas in ‘Early Lory’ it was lower. However, in 2011 no difference was observed between control and covered trees for all cultivars. Photosynthetic rate of ‘Early Star’ and ‘Van’ in 2010 was not affected by the covering, while in ‘Ferrovia’ it decreased. In 2011, the photosynthetic rate of all cultivars was the same between covered and control trees. Furthermore, the threeyear observations on the climatic conditions during the covering period indicated that they may also have an influence on fruit quality. Covering of the cherry trees with the plastic polyethylene films increased marketable yield and did not have any adverse effect on fruit quality.