Grape Berry Morphology in Semi-Arid Climate of Tekirdağ: Evaluating the Effects of Environmental Factors and Stress Applications

Abstract

The growth and development of grapes are influenced by various biotic and abiotic stresses. The presence of Vitis vinifera L. on Earth is threatened by the increase in abiotic stresses and biotic stresses due to global warming. On the other hand, grape quality and, consequently, berry characteristics can also be negatively affected by these stress factors. The hypothesis of this experiment is to determine the effects of biotic and abiotic stresses applied five days before harvest on the berries of live grapevines under field conditions. For this purpose, for two years (2016 and 2017), Cabernet-Sauvignon and Merlot grape varieties grafted onto the SO4 rootstock at Te-Ha Corp. vineyard were used. In the late pre-harvest period (five days before harvest), seven stress applications, including control, were implemented. The stress application methods included control, impact (1 minute with a plastic hammer at 08:00 and 19:00), leaf removal (removing all leaves), leaf injury (injuring all leaves by hitting with a stick), UV-C (1 minute at 08:00 and 19:00), vibration (1 minute of vibration at 08:00 and 19:00), and Botrytis cinerea Pers ex. Fr (once). The measurements of the features performed are as follows, in order: berry width-length (mm), bery volume (cm3), berry skin area (cm2/grain), berry skin area/berry flesh volume ratio (cm2/cm3), berry fresh-dry weight (g), 100 berry fresh weight (g), berry density (g/cm3), and % dry weight. As a result, it was observed that the applied abiotic and biotic stress treatments did not negatively affect berry characteristics in two years, especially in the second year. Therefore, the application of Shock action, UV-C, Vibration, Leaf injury, Leaf removal, and Botrytis cinerea for improving grape quality was found not to be objectionable.