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United States Department of Agriculture

Agricultural Research Service


Location: Horticultural Crops Research

2010 Annual Report

1a. Objectives (from AD-416)
1. Investigate leaf anatomy and morphology of well-watered and water-stressed grapevines using light and electron microscopy. 2. Monitor berry ripening and fruit quality characteristics of well watered and water stressed grapevines.

1b. Approach (from AD-416)
Research will be conducted on two cultivars in a greenhouse and drought conditions will be simulated. Leaves will be tagged on the vines of both cultivars to determine leaf age. During the dry-down and re-watering cycles, the physiological, anatomical, and morphological characteristics will be measured in both cultivars to assess drought resistance. Prior to sampling tissues for all microscopy studies, photosynthesis, dark respiration, and stomatal conductance will be measured on leaves of well-watered and water-stressed grapevines. Fruit quality characteristics such as Brix, pH, titratable acidity, color etc., will be measured to examine ripening behavior and quality characteristics during dry-down and re-watering cycles. Documents Grant with Washington State University. Formerly 5358-21000-034-32G (12/2008).

3. Progress Report
Vines of Cabernet Sauvignon, Grenache, and Zinfandel were potted. We characterized some physiological and anatomical drought adaptive features with the purpose of identifying drought resistant cultivars. Different levels of drought were induced by supplying 75, 50, 25, 0 % of the daily water consumption of the control. The relative water content (RWC) was measured in all three vine types. RWC expresses water content in percent and is a useful indicator of state of water balance of the vine in terms of physiological consequence of cellular water deficit. RWC decreased with increasing drought conditions in each cultivar. Among the three, Zinfandel and Grenache showed a higher RWC compared to Cabernet Sauvignon indicating their improved ability to withstand drought. Between Zinfandel and Grenache, the latter variety appeared to be more tolerant to drought conditions. During the current season, gas exchange and anatomical drought adaptive features such as surface morphology, leaf anatomical parameters, amount of wax, and vein density will be measured to determine drought-withstanding ability of these varieties. Methods of ADODR monitoring included meetings, e-mail, and phone calls.

4. Accomplishments

Last Modified: 06/24/2017
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