Grafting: A Growing Science with Potential and Needs
For growers of fruit-producing vegetable crops, grafted plants are versatile, scaleable solutions to production issues. Grafted plants speed the delivery of new traits to a range of farms, enhancing farm resiliency and profit potential. Grafted plants can also be produced and sold by growers as an added revenue source.
Grafted plant production in the U.S. increased from virtually zero in 2012 to approximately 8 million plants annually for watermelon and tomato in 2020. Despite this growth, U.S. propagators currently supply less than 1% of the estimated demand for grafted vegetable plants. And growers often lack guidance on optimal management practices for grafted plants.
Our team is a coordinated, comprehensive, national research-extension effort to ensure the U.S. vegetable industry prospers from grafting. Our team integrates resources from ten U.S. universities and the USDA Horticultural Research Laboratory in Ft. Pierce, Fla. industry partners to guarantee the timely, direct access to relevant, current, comprehensive, and research-based information for preparing, distributing, and growing grafted vegetable plants.
Vegetable Grafting Team Goals
Rootstock Selection / Genetics
Building Crop Resilience
A main research focus is evaluating rootstock for resistance to diseases and poor growing conditions. Resistance properties in common rootstocks can be shared to other varieties through grafting. Pictured below, researchers evaluate grafted tomatoes for resistance to Verticillium wilt.
We also examine variety responses to abiotic stressors such as water, temperature, and fertility. Pictured here is an evaluation of watermelon varieties in response to low nitrogen conditions. Frequent communications and partnership with growers helps us focus on relevant and emerging production issues.
Our grafting research investigates all steps of grafting through harvest, post-harvest handling and fruit quality. Below, researchers from North Carolina State University prepare samples of grafted watermelon for lycopene analysis.
Our team continues to evaluate and develop new rootstock selections and share results with growers and other researchers. We also maintain catalogues of rootstock compatibility and suppliers, available to the public on this site.
Grafting Best Practices
As an emerging U.S. production option, much work has been needed to optimize grafting production at different scales and production systems. Our team has studied various alternative technique including higher grafts on tomato plants to minimize disease from soil contact with grafting site. In the trial pictured here, we compared grafts made using acrylamide glue (left) and commercial grafting clips (right).
Low-cost healing method/system for regional needs.
The post-grafting healing process is a critical control point to increase grafting success. Our team has worked to develop and advance propagation systems that can be easily implemented on farms that do not specialize in transplant propagation.
Grafting is a time-consuming process. Better tools for mechanization could advance U.S. grafted plant production, reduce reliance on imports, and create new economic opportunities for U.S. growers.
Best practices, based on available research, can be found in our team’s Grafting Manual, available for free download at this site. (Last updated on provide date.)
Domestic Industry Development
In addition to the resources on this page, our team offers workshops and hands-on training like the one pictured here held in Grand Rapids, Michigan. See our Events Page to find a grafting program near you or go to our Grafting Experts page to see possibilities for speakers or technical advice. These events also provide valuable grower feedback for future research and education initiatives. Our team also includes a stakeholder advisory committee and many on-farm partners who help provide leadership and direction for our team.
Our research and other project work supports graduate and undergraduate students who will lead the next generation of grafting advances. Visit our Annual Meetings of Professional Societies page to find vegetable grafting related research pursued by plant scientists from other professional societies. We also maintain a Reference Database which catalogs recent research in grafting and other academic resources. Interested in working with one of our researchers for a Master’s, PhD, or post-doctoral work? See our listing of Grafting Experts.
Our team is also looking at supply chain analyses, enterprise budgets, and other logistical considerations to help the grafting industry grow. Check out our team’s Vegetable Grafting Decision Support Tool, which allows farmers, consultants, extension professionals, and others to analyze the economic costs and benefits of using grafted plants in crop production. Enter information specific to your situation to help determine whether using grafted plants is economically feasible.
Work and programs on this website are supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, Specialty Crops Research Initiative including grant # 2016-51181-25404.
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.