In 1995, the College of Agriculture, Biotechnology and Natural Resources
(CABNR) at the University of 
Nevada,
Reno (UNR) and Tahoe Ridge Vineyards and Winery teamed-up to establish
a 1,080 vine experimental vineyard comprising 12 varieties of Vitis vinifera
wine grapes in Reno, Nevada. These grape varieties were selected based
upon their ability to produce quality wines in other regions that have
similar climates to the Reno-Minden area (Bonn, Germany; Reims, France;
Christchurch, New Zealand; Yakima, Washington). Some of these grape varieties
have adapted better than others at the UNR vineyard.
Winter dieback had a major impact on survival and productivity over the first five years. We have replanted 15 to 20 percent of the vineyard yearly. Of the 12 varieties, we have removed two, Muscat Blanc and Muller Thurgau, in the spring of 2001 and replaced them with Syrah and Merlot. The Muscat Blanc and Muller Thurgau have been the most sensitive varieties to cold and have not produced any grapes. The most promising varieties are three white grapes and one red grape. They are Semillon, Chardonnay, White Riesling, and Lemberger. Some of these results were not expected based upon past performance of these varieties in other similar regions (Washington and Colorado). This points out that it is important to conduct variety trials in each region of interest, because they will perform differently (unpredictably) in different areas.
Irrigation can have an important impact on grapevines in semi-arid regions. Regulated-deficit irrigation practices have had a substantial impact on the vineyard survival and on grape and wine quality since it was introduced several years ago. Only two plants in the entire vineyard died in the winter of 2001/2002. Survival again looks very good for the winter of 2002/2003 and 2003/2004. In the summer of 2000, we applied water at 75 percent of crop Et (evapotranspiration), once plants reached a water potential of minus 10 bars (-0.1 MPa). This resulted in a total of 9 applications for the entire season resulting in an eighty percent reduction in water use from the previous year (when regulated-deficit irrigation was not being used). Over the last three years, using regulated-deficit irrigation, we have average 0.27 acre feet per year (a very low level of water application). Overall vine quality was improved with this watering schedule. In addition, wine quality was substantially improved with more intense color and flavors. We intend to pursue this type of irrigation regime in the following years. This water savings is extremely significant in arid Nevada. For example, Churchill County farmers produce quality alfalfa hay with an average application of 3.5 acre feet of water per acre per season (12 times more water than our application to grapes). Thus, it would seem that this area may have its own unique set of conditions which favor varieties not previously predicted. Further variety trials are warranted.
Northern Nevada can produce excellent quality wines. The sugar to acid
ratio of the grape musts and juices for many of the varieties reached
the
minimum optimum quality value of 3.0 over the three grape producing seasons
we have had so far. A 1999 White Riesling made from grapes at UNR by Tahoe
Ridge Vineyard and Winery won a silver medal at the Nevada State Fair.
The harvest in the year 2000 was very small due to a late frost in May.
The harvests in 2001, 2002 and 2003 were of excellent quality and the
wines made by UNR from these grapes are being evaluated . This pilot study
along with previous work done by Tahoe Ridge Vineyard and Winery has led
to the conclusion that wine grapes can be successfully grown in Northern
Nevada and that it is possible to produce excellent quality wines.An economic
analysis should be available by the end of 2004.