Adaptive Pruning of Cold-Hardy Commercial Wine Grape Cultivars

Project Overview

Project Type: Partnership
Funds awarded in 2023: $48,166.00
Projected End Date: 04/01/2025
Grant Recipient: Iowa State University Extension and Outreach
Region: North Central
State: Iowa
Project Coordinator:
Randall Vos
Iowa State University Extension and Outreach


  • Fruits: grapes


  • Crop Production: Pruning
  • Farm Business Management: labor/employment

    Proposal abstract:

    Several cold-hardy wine grape cultivars have been released from breeding programs.  These cultivars are the base of wine grape industry in many states in the North Central Region. While their cold hardiness and wine quality have been researched and reported, few research-based cultivar specific viticulture practices have been investigated. 

    Growers of cold-hardy grapes generally live in regions of abundant rainfall, which predisposes vines to fungal infections.  Differing pruning methods can be used, which can impact vineyard yield and predisposition to disease carryover.  Pruning is one of the more labor-intensive practices in growing grapes.  Grapevine trunk diseases are increasing in prevalence, which has reduced the recommended timeframe to prune.  Additionally, labor is increasingly difficult to source, so growers are looking to mechanize what vineyard practices they can.

    This project will investigate pruning to canes and differing spur lengths to determine what impact this may have on yield, fruit quality, canopy, and incidence of disease.  Partial and full mechanical vineyard management will be trialed in comparison with hand management to determine what impact this may have on the fruit and vine characteristics.  This will provide growers with information to make informed decisions on how to prune these relatively new grape cultivars. 

    Project objectives from proposal:

    1. Quantify fruitfulness of nodes of recently introduced cold-hardy grape cultivars at locations along canes.
    2. Develop pruning recommendations for recently introduced cold-hardy grape cultivars.
    3. Evaluate potential for mechanically pruning cold-hardy grape cultivars on high wire cordon training systems.
    4. Compare disease infection incidence between mechanically pruned and hand pruned vines.
    5. Familiarize growers of cold-hardy grape cultivars with successful and scalable mechanical pruning options.
    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.