INFLUENCE OF THE PLASTIC COVER ON THE PROTECTION OF SWEET CHERRY FRUIT AGAINST CRACKING, ON THE MICROCLIMATE UNDER COVER AND FRUIT QUALITY

摘要

To study possibility of protection of sweet cherry fruit against cracking several rows of ‘Lapins’ sweet cherry (Prunus avium L.) trees grafted on ‘Colt’ rootstock, spaced 5 x 2.5 m and trained to a central leader were covered with a plastic foilto a height of 5 m. Several rows were left uncovered as a control. In the years 2016 and 2018, sun irradiation, air temperature and fruit quality were evaluated. The plastic cover reduced solar irradiation under the tunnel roof by around 40%. Light distribution within tree canopies was depleted by roughly 50%, but in the lower parts of the tree canopies, it was reduced to 6%, which is below the critical level (20%) estimated for apple trees. These results indicate the necessity to remove the covers as soon as possible after harvesting. Mean daily temperature near the ground was lower under the covers than outside, but at the height of 4.0 m, daily mean temperature was 0.4°C higher and mean temperature during midday hours was 1.5°C higher. The plasticcovering reduced the fruit cracking from about 20% to 2% in both seasons but did not affect the fruit yield. The plastic covering did not affect the firmness and antioxidant activity and total anthocyanin content, but in the year 2018, it reduced the mean fiuit weight, soluble solid, titratable acidity, dry matter and total polyphenols content.