Evaluation of Root System Conversion Methods in the Lodi-Woodbridge

Root system conversion methods were evaluated in an own-rooted Sauvignon blanc vineyard in the Lodi-Woodbridge District. The root system conversion methods included in this study were approach grafting 1992 (rootstock rooting planted next to the vine and grafted in 1992), interplanting (rootstock rooting planted between vines in the row and budded in 1993), and an ungrafted control. Freedom rootstock was used in this experiment. Vines from the approach grafting 1992 treatment which failed to take were not regrafted in 1995. Also, the interplanting treatment was not rebudded. Our goal was to focus on the performance of converted vines. Growth and development of interplanted vines was limited due to shading from existing vines. Suckering was done twice during the growing season. Experimental plots were periodically inspected during the season. Yield data were collected at harvest on September 8, 1995. Berry samples were collected at harvest and fruit composition determined. Growth data were collected at pruning time on February 10, 1996. Percent conversion was also determined at pruning. Root system conversion method did not significantly affect yield, fruit composition, or growth during 1995. The number of approach grafted vines successfully converted has declined in most plots due to mechanical damage and weak rootstock growth. In addition, growth of interplanted vines has been poor due to shading. These results demonstrate the difficulty in managing young and mature vines planted in the same vine row. Under the conditions of this study (existing vines having a vigorous canopy), interplanting in the vine row was not an effective means of vineyard conversion.