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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #291297

Title: Leaf removal in cool seasons enhances ‘Pinot noir’ anthocyanins

item Lee, Jungmin
item SKINKIS, PATRICIA - Oregon State University

Submitted to: American Society of Enology and Viticulture Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 4/15/2013
Publication Date: 6/25/2013
Citation: Lee, J., Skinkis, P.A. 2013. Leaf removal in cool seasons enhances ‘Pinot noir’ anthocyanins. American Society of Enology and Viticulture Annual Meeting Abstracts. P78.

Interpretive Summary:

Technical Abstract: ‘Pinot noir’ grapes were harvested from a control (no leaf removal) and three complete leaf removed cluster zone treatments, which were initiated at three separate pre-véraison growth stages (bloom, grain-pea size, and bunch closure). Control and leaf–removed treatments were monitored and maintained until harvest for four growing seasons (2008-2011). The two most recent vintages (2010 and 2011), which were cooler than normal Oregon growing seasons, were evaluated for fruit quality. Experiments were conducted at two commercially operating Oregon vineyards (Willamette Valley AVA; site A= ‘Pinot noir’ 115/ 420A and site B= ‘Pinot noir’ 777/ 3309C). Fruit maturity indices, anthocyanin composition, and tannins were examined at harvest. Leaf removal initiated at bloom and maintained until harvest produced maximum anthocyanin accumulation in ‘Pinot noir’ grapes (site A= 85.24 mg/100 g and site B= 125.06 mg/100 g) compared to no leaf removal (control; site A= 57.91 mg/100 g and site B= 97.56 mg/100 g). Leaf removal did not alter most fruit maturity indices (berry weight, pH, and % soluble solids), and whole berry tannin levels were similar to no leaf removal (control). Even the last leaf removal initiation period (bunch closure) increased grape anthocyanin (site A= 73.22 mg/100 g and site B= 118.93 mg/100 g) compared to control, but total anthocyanins were lower than grapes from bloom leaf removal. If Oregon winegrape growers desire the highest achievable levels of anthocyanins in their ‘Pinot noir’ grapes during cool growing seasons, leaf removal initiated at bloom and maintained free of leaves until harvest is recommended. If leaf removal around bloom is not possible due to labor availability, similar results can be achieved by removing leaves between bloom and bunch closure to increase ‘Pinot noir’ anthocyanin accumulation.