The Oregon wine grape industry has experienced warmer, drier summers over the past decade. The first grafted vineyards were planted to three vigor-reducing rootstocks (101-14, 3309 and Riparia Gloire). However, with drier conditions, growers question the suitability of these rootstocks for the Willamette Valley, and there is great interest in understanding how rootstocks can be selected to help determine suitability for dry-farming and/or optimizing irrigation water in the region. Over three growing seasons, we are evaluating an established OSU rootstock trial (planted in 1997), with focus on Pinot noir growth response on 19 rootstocks and compared to own-rooted vines. We are monitoring phenological advancement, yield, basic fruit ripeness, YAN, anthocyanins and phenolics. Findings from this research will help growers make new vineyard plant material selections, by allowing them to consider the performance of varied rootstocks locally and under dry-farmed conditions.
- Compare vine growth stages, vine health, and fruit productivity of Pinot noir grafted to different rootstocks.
- Compare differences in fruit composition of Pinot noir grafted to different rootstocks.
Importance to the Oregon wine community
The wine industry has continued interest in rootstock performance with new vineyard development and seasonal climate change in the region. However, Oregon growers have little experience with rootstocks outside of what is currently being grown, and there are no data available from regional field studies to indicate the best-performing rootstocks for vineyards long-term under the Willamette Valley’s cool climate and mostly dry-farmed vineyards. With recent changes in vineyard production, such as increased target yields (i.e., less crop thinning) and the movement toward no-till practices and/or no herbicide use, it is unclear how different rootstocks will perform under these conditions. This study is evaluating a mature rootstock trial to help provide the industry with information on best-suited rootstocks.
Additional support for this project was provided by Erath Family Foundation for purchase of equipment to allow more streamlined plant water stress data collection starting in 2021.
Dr. Patty Skinkis conducts applied research and as an Extension Specialist, Patty develops educational programs and informational publications for the Oregon wine and grape industry. Her research focuses on applied viticulture and whole plant physiology to understand causes and manage vine vigor/vine balance, and impacts on fruit composition and wine quality. Her research also includes work on yield (from bud fruitfulness to crop thinning), canopy management, sustainable viticulture, and understanding factors that drive industry production decision-making. Her outreach efforts include bringing industry and academics together in technical groups to foster information exchange. She also teaches viticulture at Oregon State University. Her efforts expand beyond Oregon, as she is a member of the National Clean Plant Network – Grapes Advisory Board, is an associated editor for the American Journal of Enology and Viticulture, and served as a board member and held leadership positions in the American Society for Enology and Viticulture.
2020-21: Year 1 Update
In its 2020-21 fiscal year, the Oregon Wine Board of Directors granted $350,000 to researchers for eight projects with the potential to advance quality grape growing and winemaking in Oregon. The update below is part of a series to let industry members know about the status of these projects.
Progress so far
Vine growth, yield, and fruit composition of Pinot noir grafted to 19 rootstocks and own-rooted vines were quantified during 2020. The vineyard was 23 years old, and we hypothesized cumulative impacts of the rootstock on vine growth would be distinguished by rootstock. Specifically, we hypothesized that Riparia Gloire and other vigor-reducing rootstocks, such as 101-14, 3309C, and 420A, would have reduced canopy growth compared to other rootstocks not commonly planted in Oregon due to high vigor potential, such as 110R, 140R, 1103P, and 161-49.
Results show that the majority of rootstocks performed similarly for vine canopy growth and fruit production. However, Riparia Gloire, 44-53, and 3309C had the lowest pruning weights, indicating low vigor vines, and 161-49 and 1616 had the highest pruning weights, indicating vigorous vines. Despite vigor differences, there were no differences in growth stage advancement at bud break, bloom, or fruit set. By the start of véraison Riparia Gloire and SO4 had the most advanced color development, while 101-14, 3309C, and own-rooted were the least advanced. However, within six days, the rootstocks became less different in percent of berries colored, and 3309C had the highest rate of color change.
There were no differences in rootstock yield except for Riparia Gloire and SO4, which had the lowest and highest yields, respectively. Berry ripeness did not differ for most rootstocks. However, Schawarzmann had higher Brix than 420A, 5BB, 125AA, own-rooted, 5CTE, and 99R. There were few differences in pH and variable differences in titratable acidity.
We anticipated that rootstock may impact berry phenolics through vine stress and/or differences in canopy microclimate. However, there were no rootstock differences in total anthocyanin or phenolic content, and only minor differences in total tannins. We also anticipated that vine vigor conferred by rootstock may affect berry nitrogen, but there were few differences in juice primary amino N except for 1616 and 5BB, which had more than double the primary amino N than 44-53 and own-rooted vines.
This first year of data analysis suggests that rootstock has the greatest impact on vegetative growth and yield, thereby causing some differences in vine balance. There is less impact on Pinot noir phenological advancement, fruit ripeness, berry N, or phenolics at harvest.
The research will continue in 2021 and 2022 to evaluate seasonal effects on the vine performance. More detailed phenological data and plant water stress measures will be taken in these two growing seasons to discern impacts of rootstocks that may confer drought tolerance.
2021-22: Year 2 Update
In its 2021-22 fiscal year, the Oregon Wine Board of Directors granted $289,000 to researchers for six projects with the potential to advance quality grape growing and winemaking in Oregon. The update below is part of a series to let industry members know about the status of these projects.
Progress so far
Vine growth, yield, and fruit composition of Pinot noir grafted to 19 rootstocks and own-rooted vines were quantified since 2019. The vineyard was 23 years old at the outset of the evaluation period, and we hypothesized cumulative impacts of the rootstock on vine growth would be distinguished by rootstock. Specifically, we hypothesized that Riparia Gloire and other vigor-reducing rootstocks such as 101-14, 3309C, and 420A would have reduced canopy growth compared to other rootstocks not commonly planted in Oregon due to high vigor potential, such as 110R, 140R, 1103P, and 161-49. Results show that the majority of rootstocks performed similarly for vine canopy growth and fruit production. However, Riparia Gloire and 44-53 had the lowest pruning weights, indicating low vigor, and 1616, 5BB, 125AA, and 161-49 had the highest pruning weights, indicating vigorous vines. The commonly grown 101-14 and 3309C had lower pruning weights than most other rootstocks, although they fell within the optimum vigor range for the study. Most rootstocks did not differ in yield, except with 420A having higher yields than Schwarzmann, 44-53, Riparia Gloire, and own-rooted vines, based on 3-year means. Berry ripeness differed by rootstock, with higher vigor vines having lower sugars, lower pH and higher titratable acidity by harvest, but all within acceptable ranges for wine production (>23˚Brix at harvest). We anticipated that rootstock may impact berry phenolics through vine stress and/or differences in canopy microclimate. Riparia Gloire had higher concentrations of anthocyanin, phenolics, and tannins in the berries compared to other rootstocks, but berries from most rootstocks did not differ from each other. We also anticipated that vine vigor conferred by rootstock may affect berry nitrogen, and lower vigor vines had lower nitrogen compared to those of high vine vigor. So far, the findings indicate rootstock has the greatest impact on vegetative growth and yield, thereby causing differences in vine balance that has the greatest impact on from vines most out of balance (both high and low vigor).
This research continues in 2022 to evaluate the seasonal effects on the vine performance. The 2022 season will be the second season of water stress measures to discern rootstock drought tolerance but the fourth season looking at impacts on growth, yield, and basic fruit ripeness. As we advance this research, we will focus on different aspects of vine performance over time. We will also update the Rootstocks for Oregon Extension publication to provide practical information for industry.
2023: Final Report
Vine growth, yield, and fruit composition of Pinot noir grafted to 18 rootstocks and own-rooted vines were evaluated during three growing seasons, 2020-2022. The vineyard was >20-years-old, and we hypothesized cumulative impacts on Pinot noir vine growth would be distinguished by rootstock. Specifically, we hypothesized that Riparia Gloire and other vigor-reducing rootstocks, such as 101-14, and 3309C, would have reduced canopy growth compared to other rootstocks not commonly planted in Oregon due to high vigor potential, such as 110R, 140R, 1103P, and 161-49. Results show most rootstocks performed similarly for phenology, vegetative growth, and fruit yield. However, there were some key differences amongst the rootstocks. Riparia Gloire, 44-53, Schwarzmann, and 3309C had the lowest vine vigor and 5BB, 125AA, and 161-49 had the highest vigor based on dormant pruning weights. These differences were visible in the field during the mid-late summer. Of the subset of vines monitored for plant water stress, the most stressed vines were Pinot noir on 101-14 while Pinot noir on 5BB, 140R, and 1103P had less water stress over the two years. The more drought-tolerant rootstocks had less water stress, higher pruning weights and average yields. There were some differences in fruitfulness, with SO4 having the greatest fruitfulness while Riparia Gloire having the lowest. There were yield differences by harvest, with 420A having higher yields and Riparia Gloire and 44-53 having the lowest yields consistently. The impact on yield is mostly explained by differences in cluster weight. Pinot noir fruit ripeness at harvest differed by rootstock, with the most advanced ripeness being in Pinot noir on Riparia Gloire, which had the highest total soluble solids, highest pH, and lowest titratable acidity but also the highest crop load. Crop load was altered by rootstocks and did not correlate well with ripeness parameters. We anticipated that variations in canopy size created by rootstock vigor would affect berry phenolic concentration or content through vine stress and/or differences in light exposure in the cluster zone based on canopy size differences. Pinot noir on Riparia Gloire had the highest total anthocyanin, phenolic, and tannin, but Pinot noir on other rootstocks had similar concentrations despite different levels of plant stress and/or canopy size/exposure. This research shows that rootstock had the greatest impact on vegetative growth and yield, by way of differences in water stress tolerance, thereby causing some differences in vine balance, although those differences in vine balance did not impact fruit composition linearly.