Evaluation of Root System Conversion Methods in the Lodi-Woodbridge District
Root system conversion methods were evaluated in three vineyards using Cabernet Sauvignon grafted on Chenin blanc, Semillon grafted on Napa Gamay, and own-rooted Sauvignon blanc, respectively. The root system conversion methods included in this study were approach grafting 1992 (rootstock rooting planted next to vine and grafted in 1992), approach graftinq 1993 (rootstock rooting planted next to vine and grafted in 1993 when canes had sufficient diameter for grafting), interplanting (rootstock rooting planted between vines in the row and budded in 1993), and an ungrafted control. Freedom rootstock was used in all experiments. Vines from the approach grafting 1992 treatment which failed to take were regrafted in May 1993. Budding of interplanted rootstocks occurred in June 1993 and approach grafting 1993 vines were grafted in July 1993. The experimental plots were periodically inspected during the growing season. Yield data for Sauvignon blanc and Semillon were collected at harvest on September 20, 1993. Cabernet Sauvignon vines were harvested and yield data collected on September 29, 1993. Berry samples were collected at harvest and fruit composition determined. Percentage take and pruning weight were measured on January 11-12, 1994. Approach grafting done in 1992 and interplanting produced the greatest percentage conversion. Approximately 80%of vines in these treatment categories have been successfully converted to resistant rootstock. Root system conversion method did not significantly affect vine performance.