Evaluation of New Winegrape Varieties for the San Joaquin Valley
Fifty six different red and white wine grape selections originating from warm-climate Mediterranean regions, and/or believed to have traits that would be desirable in a warm climate wine region, are being evaluated at the Kearney Agricultural Center, in Parlier, CA. Most of the selections tested were recently released to the industry from Foundation Plant Services, so certified selections have not previously been evaluated in California. All vines are on 1103P rootstock, trained to bilateral cordons, and most were spur pruned, leaving 8 or 9 two-bud spurs per meter of cordon. However, beginning in 2013, certain varieties have also been subjected to simulated machine pruning. In general, we attempted to harvest all white varieties at 22 Brix, and reds at 24 Brix, but certain selections were picked at higher or lower Brix depending on a number of factors, including the desired wine style. At harvest, yield components, rot incidence, and basic chemistry were determined and wine lots were made from some selections at Constellation Brand’s experimental winery. Many varieties were harvested earlier in 2014 than they were in previous years. Fiano, a white variety, has typically been the earliest variety harvested (early August), but several other early whites and a red variety were also harvested on 11 August 2014, the same day as Fiano. About a half dozen red and white varieties failed to meet their target soluble solids level even though the last harvests occurred in early November. Yields ranged from less than 4 kg per vine for Prieto Picudo to about 30 kg of fruit per vine from the machine-pruned Counoise, a red variety. Red and white varieties varied widely with respect to harvest date, pH, and titratable acidity. Wines from the trial will be made available for tasting and analysis in 2015, as they have been in most of the past several years. Twelve varieties which performed very poorly in the first two years of the trial were topworked to new selections in 2014, with full crops expected in 2015. Some varieties were subjected to simulated machine pruning to determine if yield and rot problems could be ameliorated. In most cases, machine pruning substantially reduced rot and increased yields, but the higher yield severely delayed ripening of some varieties and, in Falanghina, was associated with slightly higher levels of rot.