Influence of Trellis-Training System and Rootstock on Optimum Spacing of Cabernet Sauvignon Vines Within Rows

The second year’s data from five-year-old Cabernet Sauvignon vines grown at the south Oakville Experimental Vineyard comparing within row vine spacings of 1, 2, and 3 meters showed average crop yields of 8.8, 8.3, and 7.3 tons/acre, respectively, when data of six trellis systems and two rootstocks were averaged together. The higher yield of closer vine spacing was mainly due to greater number of vines, shoots and clusters per acre, and to a lesser extent, berry weight. The number of berries set per cluster and cluster weight decreased with closer vine spacing but this reduction was more than made up for by the increase in shoots and clusters per unit area of land from higher planting density. The differences in yield between in-row spacing treatments was only 20%in 1994 compared to 63%in 1993, suggesting that dif¬ferences in yield due to within row vine spacing may disappear as the vines become older. With wider vine spacing there was an increase in the number of shoots, leaf area and pruning weight per vine but reduction of these parameters per meter of row length. Shoot length, leaves/shoot, internode length, leaf area per shoot and leaf area per gram of fruit decreased with increasing distance between vines within rows. The overall effect of increasing distance between vines was a reduction in canopy density and an increase in the amount of photosynthetic light in the fruiting region. The total leaf area (m2)/m row length was reduced from 4.6 for 1 m vine spacing to 2.8 for 3 m spaced vines when averaged for all trellis systems and both rootstocks. Pruning weights were similarly reduced on a per meter of row basis from 1.5 for 1 m spaced vines to 0.8 kg/m for 3 m spaced vines. Increasing the distance between vines from 1 m to 3 m sig¬nificantly reduced the level of TSS, pH, malic acid and anthocyanin per berry in fruits at harvest, however TA, K, and anthocyanin per g berry weight did not differ significantly between vine spacing treatments. Increasing vine space also reduced wine pH (and for the GDC, wine TA) but did not significantly effect ethanol concentration, wine color density or wine hue. The yield of Cabernet Sauvignon or 110R rootstock averaged 9.0 tons/ac compared to 7.1 tons/ac for 039-16 stock. The higher yields obtained with 110 are compared to 039-16 stock was true for all vine spacing and trellising treatments. The higher yields produced with 110R stock was mainly due to greater number of shoots and clusters per vine and to a lesser extent to larger berries. Shoot length and leaf area per shoot of vines on 110R stock were about 30%greater than vines on 039-16 stock. Total leaf area per vine aver¬aged approximately 50%higher with 110R than 039-16 stock. Total pruning weight per vine and average shoot weight were almost doubled on 110R relative to 039-16. The greater density of 11 OR resulted in a reduction in the amount of light in the fruiting region, however, the level of light did not limit fruit bud formation and vine productivity. The ratio of leaf area/g fruit averaged 8.4 for 039-16 and 10.1 for 110R. Crop to pruning weight ratios were 9.1 for 039-16 and 6.2 for 110R. 110R fruit at harvest was significant¬ly higher in TSS, pH, K and anthocyanin than 039-16 fruit. Wines from Cabernet Sauvignon on 110R