1Dept. of Horticultural Sciences

NYS Agricultural Experiment Station, Cornell University, Geneva, NY

2Dept. of Fruit and Vegetable Sciences, Cornell University, Ithaca, NY

The New York grape breeding program places a high priority on the development of highly disease resistant grape varieties. Resveratrol, a compound produced by grapes and just a few other plants, is associated with resistance to downy mildew and Botrytis bunch rot in grapes. Moreover, scientific evidence for its role in reducing the risk of coronary disease and cancer is mounting quickly. Our goal was to screen breeding program selections for resveratrol production in order to aid in the development of disease-resistant hybrids which also carry the potential for high resveratrol content. We also sought to identify commercial varieties with high resveratrol production potential. Relative resveratrol levels in leaves and berries of 48 varieties and selections were analyzed. Highest levels of leaf resveratrol were found in Vitis aestivalis, Ill. 547-1 (rupestris x cinerea), BR14 (rupestris hybrid), Vitis longii x rupestris, Sunbelt, Couderc 13, V. aestivalis x riparia, and NY88.0517.01. Among 8 fruit samples analyzed to date, just two were high in resveratrol (Ill. 683-1 {cinerea hybrid} and NY65.0550.04). No correlation between leaf and fruit resveratrol levels could be detected. Fruit analyses are still underway.

This research will have a dual benefit to the grape and wine industry. Firstly, it will lead to the development of highly disease resistant varieties which would be better suited for IPM and/or organic approaches to grape production. The costs and potential risks associated with fungicide use would be greatly reduced through the use of disease-resistant varieties. Secondly, the development and/or identification of grapes with high berry resveratrol content, and its association with reduced risks of coronary disease and cancer, may be useful in promoting the health benefits of wine.

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Dept. of Fruit and Vegetable Science

Cornell University, Ithaca, NY

Seventy red wines submitted by New York wineries were analyzed for resveratrol. The range was from 1 to 46 micromolar resveratrol. A 46 micromolar resveratrol wine is extraordinary. We had considered 25 micromolar the highest possible concentration. We do not yet have an explanation for the cause of this high concentration.

New York Pinot Noir averaged the highest in resveratrol of all wine types analyzed. Sixty-five percent of New York Pinot Noir were above 10 micromolar and the average of the seventeen analyzed was 14 uM. New York Cabernet Sauvignon, Merlot and Cabernet Franc wines averaged around 8 uM. Hybrid and American red table wines averaged 4 uM resveratrol.

Forty wines from regions other than New York were analyzed. The average resveratrol of New York wines of each wine style was higher than from other growing regions.

Some white wines were submitted for analysis and some non New York wines purchased for comparison. Most white wines are below 1 micromolar because resveratrol is found in grape skin.

Techniques were developed to analyze the flavonol antioxidants in wine.

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Department of Fruit and Vegetable Science

Cornell University, Ithaca, NY

Vineyard Manipulation: Results of our previous experiments demonstrated that pesticide applications can influence resveratrol production in grape skin. Eleven treatments were applied to clusters of Pinot Noir in the vineyard near harvest to determine the effects on berry resveratrol. Berries were collected for 6 days. The berries are presently being analyzed in triplicate. It is too early to speculate on this year's results.

White wine: We repeatedly sampled and analyzed nine white wine cultivars near their expected harvest dates. Two cultivars were harvested and wine made on and off skins. Unfortunately these white cultivars decreased in resveratrol as harvest approached this year and we couldn’t make a high resveratrol white wine. We were able to track resveratrol and other skin components leaching into wine. We will need to analyze more white grapes to pick a cultivar suitable for making white wine with skin contact. This year's wine will be finished and tasted for evaluation of the skin contact.

Resveratrol Preparation: Pomace from red wine production was very similar in resveratrol concentration to the resulting wine. Pomace from white grapes was higher in resveratrol than the wine but as yet we have not found a high resveratrol white grape among the common wine grapes. We have only analyzed a relatively small number of white grape varieties compared to the large number of red wines analyzed.

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