Evaluation of Winegrape Clones
Pinot noir and Chardonnay. For Chardonnay, yields in 1999 were consistent with the 2-yr averages, in that Wente was the lowest at just over 3 kg/vine while 352 was among the highest at 5.2 kg/vine. Cluster number, berries per cluster and berry wt all played a role in yield differences. Cluster number varied from a low of 30 (clone 4) to a high of almost 44 (clone 352), berries per cluster from a low of 76 (clone 78) to a high of 107 (clone 4) and berry wt from a low of 0.94 (Wente selection) to a high of 1.59 (clone 4). Harvest in 1999 took place over a 9 day period from September 18 to 27. For Pinot noir, yield ranged from a low of 3.83 kg/vine (clone 13) to a high of 8.18 kg (clone 668). Cluster number varied from a low of 31 (clone 743) to a high of 54 (clone 2A), berries per cluster from a low of 74 (clone 13) to a high of 144 (clone 743) and berry wt from a low of 1.26 (clone 872) to a high of 1.57 (clone 13). Harvest occurred over a 17-day period from September 7 through September 24. Merlot and Malbec. Again in 1999, the major difference among Merlot clones was in the yield component of berries per cluster for clone 8, resulting in a significant decrease of more than 3 tons per acre. This trend corresponds precisely with the 5-year average. Despite the lower Brix of clone 8, it had the lowest Brix and highest pH both in 1999 and as a five-year average. The 1999 vintage was another difficult year for Malbec with yields on average being less than 4 tons/acre. Individually, significant differences could be seen among yields of the clones, with clone 8 showing 6.7 tons/acre versus 2.3 and 1.9 tons for clones 4 and 6, respectively. All yield components were involved including clusters per shoot, berry wt and berries per cluster. In 1999 the 11 OR rootstock showed a significantly greater yield than Malbec on 5C due to more clusters per shoot and heavier berries. There were few differences in fruit chemistry with the exception of significantly more potassium in Malbec 8 and all vines on 5C. Malbec values for the 4-year period show the dramatic yield differences among the years.