Comparative Studies on Wine Grapes on Different Trellising Systems: IL Micro-climatic Studies, Grape Composition and Wine Quality

Abstract

In a field experiment the micro-climate and grape composition of four trellising systems viz., (a) Bush vines, (b) Perold system, (c) Lengthened Perold, and (d) Slanting trellis were investigated and compared. Significantly more air movement, higher bunch and ambient air temperature as well as higher soil temperatures at 200 mm depth were recorded in the bush vines compared to the lengthened Perold and slanting trellis. Bunch temperature differences among trellising systems became most pronounced at 12h00 to 14h00. The sugar concentration in grapes from the bush vines increased at a slower rate compared to the other trellising systems and retarded the harvesting date of the former by a week. Fluctuations in soil moisture content affected both sugar concentration and berry volume positively or negatively, depending on the stage of berry development and quantity of water applied to the soil. Malic acid concentration of the bush vines juice was 1,78 g/e lower compared to the slanting trellis at harvesting time, while tartaric acid contents were the same for all trellising systems. Although a distinct relationship between micro-climate and grape composition was found, apparently no relationship existed amongst these two aspects and the organoleptically evaluated wine quality. A re-appraisal of the results of a former trial obtained in the same experimental vineyard led to the conclusion that wine quality from these different trellising systems is directly related to the incidence of Botrytis cinerea.