Changes of Vine Water Status and Growth Parameters Under Different Canopy Managements on cv. Merlot (Vitis vinifera L.)

Abstract

The climate is the dominant regulator that determines the cultivation in a viticulture region as it strongly controls vine physiology, vine growth, canopy microclimate, berry quality and finally wine components. However, the effects of climate change force vine producers to find solutions that will facilitate their adaptation processes. The importance of water management in vineyards is becoming more important every day for sustainable viticulture and winemaking. Efficient use of water in vineyards is an important issue to control the yield and to provide the targeted berry quality at the desired level. This experiment was carried out during the 2013-2014 and 2015 growing seasons to evaluate the effects of green pruning practices on water leaf potentials of 12-14 years old grapevines of cv. Merlot (Vitis vinifera L.) grafted onto Kober 5BB in the experimental vineyard of Tekirdag Viticulture Research Institute in Turkey. A completely randomized block design was used: LRMS1, LRMS2, LRMS3 represent three levels of leaf removal treatments on main shoots and LRLS1, LRLS2, LRLS3 represent three levels of leaf removal treatments on lateral shoots. Due to the relatively high soil moisture in vineyard conditions, no extreme and high-water stress levels was observed in experiment years. The main factor controlling the water status in cv. Merlot vines was largely dependent on the meso-climatic conditions and soil water availability during the growing season. However it was observed that increasing of main shoot length give rise to tendency to water stress. It was determined that leaf removal treatments on lateral shoots caused changes in shoot weight, pruning weight and Ravaz index (RI), especially in 2014 whereas the leaf removal treatments on main shoots caused changes in mentioned parameters in 2015. In conclusion, the results show that plant water condition can be managed with summer pruning taking into account of different climatic conditions and different phenological stages. Planning of canopy management practices should be done by considering long- and medium-term meteorological evaluations while short-term planning within vegetation period should be done in relation to weekly and monthly meteorological data.