Evaluation of Sierra Foothill Zinfandel Selections
Excellent quality Zinfandel wines are made from ?old vines? in California. Often the source of wood for these vineyards is unknown. It is unclear whether these vineyards are different selections or clones of Zinfandel, or if they produce superior quality because of age, vineyard site, stress, viticultural or management differences. Virus disease symptoms, especially Leafroll have long been associated with many ?old vines?. As laboratory testing for virus disease becomes more sophisticated even ?asymptomatic? popular selections prove to be diseased. While the University of California and FPMS continue to promote certified stock, there is still strong industry interest in duplicating the success of ?old vine? selections of Zinfandel, regardless of virus status or proven performance outside of the origin vineyard. By growing these selections in one location under uniform cultural practices, we will be able to evaluate any differences in these field selections. A research block was established Amador County. In 1998, budwood was collected from nine ?old vineyard? Zinfandel selections in Amador, Calaveras, and El Dorado Counties. Primitivo was also collected since there is growing interest in this cultivar. Wood was collected from 4-5 vines that appeared to be free of any virus symptoms. The wood was grafted onto St. George rootstock. Plants were grown during the summer at Sunridge Nursery in Kern County and the research vineyard was planted in March 1999. Selections include: Aparicio, Dal Porto, Deaver, Eschen, Upton, Ghirardelli, Higgins, Lubenko, Primitivo and Steiner (same source as Grand Pere)Each plot consists of 32 vines (4 rows x 8 vines) and each plot is replicated in 8 blocks across the 3 acre field. The blocking is laid out to follow soil types. Large plots were established so that wine samples could be made from the selections.Eight data vines per plot are used for viticulture measurements. Pruning weights were collected to determine vine vigor. Shoots and clusters per vine were recorded. Two berry samples were collected prior to harvest. Vines were harvested in September 2002, and data was collected, including; yield per vine, clusters per vine, berry weight, cluster weight, brix, titratable acidity, pH. There are few significant differences in these young vines and a great deal of variability based on vigor and training. Vines were thinned in 2002 to avoid overcropping.Fruit from all 256 vines of each selection was harvested, and approximately 60 gallons of wine were made from each treatment. Sample wines were tested and will be evaluated.Vines were monitored for virus symptoms. PCR testing was conducted on 50 vines and will continue as time and expense allow.