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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #174724
Title: WATER MANAGEMENT TO OPTIMIZE CANOPY, YIELD, AND QUALITY OF 'MERLOT'

Author
item Shellie, Krista

Submitted to: Northwest Center for Small Fruit Research Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 11/1/2004
Publication Date: 1/10/2005
Citation: Shellie, K. 2004. Water management to optimize canopy, yield, and quality of 'Merlot'. Proceedings of the Northwest Center for Small Fruits Conference. Boise, ID. p. 84-85.

Interpretive Summary:

Technical Abstract: A 1-acre irrigation trial was established spring 2002 in a 30-acre plot of 'Merlot' at Skyline Vineyard (Nampa,ID). Weekly irrigations were varied in amount based on local evapotranspiration and a Washington State derived wine grape crop coefficient. Four levels of irrigation were evaluated: 1) 100% of vine water requirement (FVET); 2) 70% of FVET; 3) 35% FVET until veraison and then 70% FVET until harvest (35-70% FVET); and 4) 35% FVET. Cane length, berry diameter, and leaf water potential were measured weekly. Pruning weight, yield, 100 berry weight, cluster weight, canopy PAR, seasonal trunk growth, and harvest Brix, pH, and titratable acidity were measured annually. Monomeric anthocyanins, total phenols, composite sugars and acids were analyzed in skin and juice of east and west exposed berries. Berry and leaf temperature on east and west exposed fruit were monitored continuously throughout the 2003 and 2004 growing seasons. Leaf and berry transpiration during berry stage 1 were measured in 2004. Wine was made each year from each trial plot and analyzed for total monomeric anthocyanins, intensity, and hue. Informal preference tests of experimental wines were conducted by untrained judges. Results from this research demonstrate that irrigation management practices influence vine canopy, berry size, yield, and composition of grape derived determinants of wine quality. Despite large annual differences in yield (4.6, 5.0 and 9.2 t/acres, respectively for years 02, 03, 04), highest vine water stress always resulted in lowest yield. Yield reduction was associated with smaller berry size, lower cluster weight (Table 1), and less clusters per vine. Must pH corresponded with vine water stress.