Influence of Vine Trellis Training Systems on Growth, Yield, Fruit
The 1995 season represents the fourth season of this study. The experiment being conducted is a long term investigation of the influence of trellis/training systems 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 reduction in yield or fruit quality. Results obtained in 1995 differed somewhat from results in the 1992-1994 seasons. This was in part due to the unusual environmental conditions which occurred during the 1995 growing season. Heavy spring rains and cool temperatures contributed to reduced early season growth and delayed canopy development. Unseasonable temperatures and wide fluctuations in temperature were experienced through most of the season. Minimally-pruned vines were skirted in June to reduce the crop level and facilitate cultural practices. Due to environmental conditions and crop level, harvest occurred much later (November 4) than in previous seasons. Yield was higher in 1995 than during 1992-1994 for hand-pruned treatments. As a result, there were no significant yield differences between the treatments. Significant differences were observed for components of yield. Vines which were minimally-pruned or machine-pruned had more clusters than hand-pruned vines. Berry weight, cluster weight, and berries/cluster displayed an inverse relationship with clusters/vine. Hand-pruned vines exhibited higher berry weight, cluster weight, and berries/cluster than minimally-pruned or machine-pruned vines. Trellis/training system had little effect on fruit composition in 1995. Vines which were minimally-pruned had more shoots per vine than vines receiving the other treatments. However, total vegetative growth was greatest for control (bilateral cordon) vines and was the lowest for minimally-pruned vines (mature nodes/vine). Symptoms of Eutypa infection were not observed in the plot during 1995. This result is not surprising in that symptoms of Eutypa usually first appear approximately 6-8 years after vineyard establishment. Therefore, treatment effects on Eutypa incidence should become evident in the next few years.