Influence of Vine Training System on Growth, Yield, Fruit Composition, and
The 1997 season represents the sixth season of this study. The experiment being conducted is a long-term investigation of the influence of training system on vine performance and the incidence of Eutypa dieback in a Cabernet Sauvignon vineyard. Data for the 1997 season were analyzed by factorial analysis to show the effect of two distinct soil types within the experimental site. The soil change occurs in the middle of the vineyard, evenly dividing the experimental plots into either a high capacity soil (Columbia Silt Loam) or a low capacity soil type (San Joaquin Loam). Training system had a significant effect on yield and components of yield. Yield was highest for the minimal pruning treatment and lowest for head-trained, cane-pruned treatment. Minimally-pruned vines had the greatest number of clusters and the lowest cluster weight, berry weight, and number of berries per cluster when compared to the other treatments. Machine-pruned vines had yields greater than the hand pruned treatments but less than minimally-pruned vines. In general, large yield for the minimal pruning treatment resulted in delayed fruit maturation. Soluble solids and pH were lower for vines which were minimally-pruned while titratable acidity was higher. However, fruit composition for minimally-pruned vines was quite suitable for production of high quality red table wine. Fruit quality was significantly affected by soil type. Soluble solids and anthocyanin content were greater in the low capacity soil. Training system also had a significant effect on vegetative growth. Growth, as measured by mature nodes per vine, was lowest for bilateral cordon and head-trained, cane-pruned vines. Vines which were minimally-pruned had more shoots per vine than all other treatments. Symptoms of Eutypa infection were observed in the plot during Spring 1997 for the second consecutive year. As was the case in the 1996 season, Eutypa symptoms were only observed in hand-pruned, cordon-trained treatments.