Evaluation of Rootstock Effects on the Establishment of Seedless Table Grapes in High Soil pH Conditions

Commodities

Practices

The goal of this project is to determine performance of new seedless table grapes in the Upper Midwest and the potential enhanced establishment and production of these grapes using rootstock selection in challenging growing conditions, including high pH soil conditions. Although cold-hardy cultivars enable grape production under harsh growing conditions, vineyard establishment for table grape production remains a major bottleneck in the region, often leading to early vine failure and increasing economic risk for Specialty Crop growers, especially for high-value crops such as locally grown seedless table grapes. This study will compare newly released own-rooted table grape vines (University of Minnesota (UMN) Northern Glo Grape Series), with vines grafted onto Riparia Gloire (standard rootstock) and a new University of Minnesota rootstock selection, breed for Midwestern winter and higher pH soil conditions, to enhance vineyard establishment, vigor, and performance. This project will combine grafting on rootstock and field evaluation to produce practical, field-based results. Results from this project will be shared with growers through field days, publications, and outreach activities, providing practical recommendations to support sustainable and regionally adapted seedless table grape production. Results will also be shared nationally through the annual NE2220 multistate project on Grape Cultivar Evaluation and the American Society for Horticulture Science or the Midwest American Society of Enology and Viticulture meeting.

Farmers' economic viability will be enhanced by this project through the minimization of early vine failure and establishment risks, which are major costs in vineyard development. Having better rootstock options for this region will enable growers to establish vineyards more reliably, reducing replanting costs and increasing long-term productivity for high-value table grapes. Moreover, this project will promote long-term vineyard sustainability by enhancing plant adaptation to existing soil conditions, particularly in high-pH soils, thus reducing the need for soil amendments and other inputs. Improved establishment and root function can also promote healthy growth and adaptation to high-pH soils. Eventually, this will contribute to a better vine management.

Improving growers' quality of life is another important aspect of this project, as it will likely reduce the uncertainty and risk associated with vineyard establishment. Ultimately, this enables more dependable and confident production decisions by reducing financial stress and labor costs associated with vine failure. Supporting successful table grape production will contribute to local agricultural variety by providing more opportunities for specialty crops, reinforcing regional food systems, and increasing the supply of locally grown fruit for consumers.

This project aims to produce both learning and action outcomes for Specialty crop producers, grape growers, and other stakeholders in the Upper Midwest, especially those interested in new perennial fruit crops to diversify their crop portfolio. Growers will have a better understanding of the new Northern Glo Grape seedless cultivars (released in 2025) and how rootstock selection improves vine establishment, survival, and early growth under challenging growing conditions, such as high-pH soils and northern growing zones (University of Massachusetts Amherst, 2024). While there is information on rootstocks and biotic pests for V. vinifera table grapes, there is limited region-specific information on how rootstocks affect the performance of seedless table grapes for the Midwest; thus, this project will help address this important knowledge gap by contributing information on a new rootstock selection and a broader scientific understanding of rootstock effects on table grape production. At the end of this project, growers in this region would make more informed decisions when selecting planting material, including the consideration of grafted vines and rootstocks adapted to their region and site conditions. This will lead to improved vine establishment rates, reduced vine loss, more consistent vineyard performance, and a unique addition to local food producers' crop portfolio.