Author
 |
Shellie, Krista |
|
Submitted to: Northwest Center for Small Fruit Research Proceedings
Publication Type: Proceedings Publication Acceptance Date: 10/7/2005 Publication Date: 12/3/2005 Citation: Shellie, K. 2005. Water management to optimize canopy, yield, and quality of Merlot. Northwest Center for Small Fruit Research Proceedings. Interpretive Summary: Technical Abstract: Own-rooted, four-year-old Merlot vines were exposed to four differential, evapotranspiration-based, irrigation regimes: low, medium, or high vine water stress from bloom to veraison, or high preveraison stress altered to a medium level from veraison to harvest (high-med). This multi-year trial (2002-2004) was situated at a commercial vineyard in southwestern Idaho, USA (latitude 43°28’N, longitude 116°42’W, elevation 841 m). Weekly midday leaf water potential values detected differences in vine water stress among treatments within three weeks after start of differential irrigations. Vines from high water stress plots had lower yield, smaller berry size, lower cluster weight, and less trunk growth than vines from low water stress plots. Fruit harvested from high water stress plots had lower titratable acidity and resulted in wine with higher intensity than fruit from low water stress plots. However, fruit harvested from high preveraison stress plots that experienced medium rather than high postveraison stress had similar cluster weight, seasonal trunk growth, and wine intensity as fruit from low water stress plots. The amount of water provided to these high-med plots was similar to high stressed plots in the pre-veraison period, to medium stressed plots in the post-veraison period, and about 50% less than low water stress plots. Results suggest that desirable vine and fruit attributes can be manipulated using less supplemental water by inducing a high preveraison stress that is altered to a moderate level between veraison and harvest. A biological-based indictor of vine water status with greater sensitivity than midday leaf water potential would be useful for managing irrigation scheduling to achieve optimum severity and timing of imposed vine water stress. |
