Effects of post-véraison water deficit on 'Pinot noir' yield and nutrient status in leaves, clusters, and musts

Authors: Schreiner, Roger - Paul; Lee, Jungmin

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/30/2014
Publication Date: 11/17/2014
Publication URL: http://hortsci.ashspublications.org/content/49/10/1335.abstract
Citation: Schreiner, R.P., Lee, J. 2014. Effects of post-véraison water deficit on 'Pinot noir' yield and nutrient status in leaves, clusters, and musts. HortScience. 49:(10)1335-1340.

Interpretive Summary: The impact of late season water stress on vine growth, yield, and nutrient composition of whole clusters and grape juice was investigated in Pinot noir grapevines grown under controlled conditions. Periodic drought stress that is considered to be moderate to severe applied to Pinot noir vines after veraison had no impact on vine growth and yield, nutrient status in leaves, or berry chemical composition. Although, these vine characters were altered by the growing year. These findings suggest that new Pinot noir vineyards that are planted on rootstocks and managed with drip irrigation should be tolerant of short periods of fairly severe drought stress with little impact on fruit quality.

Technical Abstract: ‘Pinot noir’ grapevines were grown in a pot-in-pot system using a red-hill-soil where volumetric soil water content ('v) was carefully controlled. Four-year-old vines were supplied with one of two irrigation regimes (wet or dry) between véraison and fruit maturity and the experiment was repeated over two years. From véraison to harvest, vines in the wet treatment received irrigation whenever 'v approached about 15% maintaining leaf water potential ('leaf) above -1.0 MPa. Vines in the dry treatment received irrigation when 'v approached 11 to 12%, and experienced significant water stress ('leaf about -1.4 MPa) before water was re-supplied. Vines were destructively harvested at véraison and at commercial maturity to determine biomass and nutrient content in current season’s above-ground tissues. Fruit yield, maturity indices, and must nutrient composition were measured at maturity. Irrigation did not influence vine growth in either year, nor did it influence yield or fruit maturity indices. Irrigation also had no influence on leaf or must mineral nutrient concentrations. Vine growth, yield, and nutrient status in leaves and musts varied by year. Vegetative growth was greater in 2007 than 2008, while yield and cluster weights were greater in 2008. Also in 2008, whole clusters obtained a greater proportion of dry matter and nutrients after véraison when differing irrigation treatments were imposed. Nonetheless, irrigation did not affect must chemical composition. These findings suggest that periodic post-véraison water deficits that are moderate to severe have no effect on berry nutrient and sugar accumulation in ‘Pinot noir’ cropped at typical levels for this variety.