Author
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Shellie, Krista |
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Submitted to: American Journal of Enology and Viticulture
Publication Type: Abstract Only Publication Acceptance Date: 5/5/2005 Publication Date: 10/1/2005 Citation: Shellie, K. 2005. Merlot vine water status impacts yield, berry and wine quality. American Society of Enology and Viticulture. 56(3):301A. Interpretive Summary: Technical Abstract: Objectives of this research were to determine how severity and phenological timing of vine water stress impacts yield components and berry and wine composition. Vines in a 1-acre trial established in southern Idaho within a commercial, 30-acre block of own-rooted, five-year-old ‘Merlot’ were irrigated weekly from fruit set through harvest at percentages of estimated evapotranspiration (ET) needs during the 2002, 2003, and 2004 growing seasons. Levels of vine water stress were classified as low (100% ET), moderate (70% ET) or severe (35% ET) and measured as midday leaf water potential (LWP). Yields of vines moderately or severely stressed were reduced 17 and 40%, respectively, with 11 and 30% reductions, respectively, in berry size. Severe water stress was associated with an increase in number of berries per cluster, a decrease in number of clusters per vine, reduced annual trunk growth, lower titratable acidity and malic acid concentration, increased incidence of sunscald, and higher intensity wine. Severely stressed preveraison vines altered to a moderate level of stress at veraison through harvest had malic acid concentrations 10% higher and berry size 14% larger than vines severely stressed through harvest, yet berry size remained smaller than low or moderate stressed vines with malic acid concentration and wine intensity similar to moderately stressed vines. Results suggest a narrow margin between beneficial and potentially deleterious levels of vine water stress and show that stress severity altered at veraison attenuates the impact of severe preveraison stress. Funding was provided by the Northwest Center for Small Fruits Research. |
