Influence of Vine Trellis Training Systems on Growth, Yield, Fruit Composition, and Eutypa Incidence of Cabernet Sauvignon Grapevines
This is the third season of a long term study to investigate the influence of trellis / training system on vine performance and the incidence of eutypa dieback in a Cabernet Sauvignon vineyard. The goal of this experiment is to develop cultural practices which will reduce vine losses from eutypa and reduce production costs without a loss in fruit quality. Vines had good early season growth with the exception of vines which were head-trained and cane-pruned. These vines displayed poor development of buds in the middle of canes. Minimally-pruned vines grew well and appeared to develop a full canopy by May. We observed that early season leafhopper damage appeared to more severe on minimally pruned vines due to their early completion of shoot growth. Minimally-pruned vines were skirted (trimmed) at approximately 36″ above the ground to reduce crop and facilitate cultural practices during June. Also, an additional drip emitter (0.5 gallon) was installed for each minimally-pruned vine to compensate for the higher water requirements of this treatment, especially early in the season. Significant differences in yield and fruit composition parameters were observed in 1994. Minimal pruning and machine pruning treatments had significantly higher yield and number of clusters than the other treatments. The head trained/cane pruned treatment had significantly lower yield than the other treatments. Treatments .with the higher yield i.e. minimal and machine pruning displayed a slight delay in fruit maturation. Trellis / training system did not significantly affect total growth of vines as indicated by mature nodes per vine. Nodes retained were highest for the minimal and machine pruning treatments. Symptoms of Eutypa lata infection have not been observed in the experimental block.