A $2.49 million USDA specialty crops grant will help researchers at seven research institutions make grafting a viable—and profitable—option for fruiting vegetable nurseries and producers.

Researchers will use the USDA Specialty Crops Research Initiative grant to design decision-support systems and various grafting technologies, as well as research disease management alternatives for growers using grafted plants.

With the loss of methyl bromide, label changes on several fumigants and fungicide-resistance problems, nursery owners and growers are seeking other ways to prevent and control crop diseases. Grafting—the practice of joining a cutting to a piece of rootstock—is widely used outside of the U.S. to manage diseases, but it has been slow to be adopted in the U.S. In fact, between 59%-81% of the total cultivated acreage in East Asia, Middle East, Northern Africa and Central America is devoted to grafted plants. In the U.S., only the hydroponic greenhouse growers have fully embraced grafting technology.

Tomato and cucurbit growers have begun to take an interest in obtaining grafted plants, but few nurseries carry the quantity of plants they need. On the other hand, nurseries are hesitant to begin mass-producing grafted plants until they see that the demand will keep up with their supply.

Frank Louws, director of the NC State University Center for IPM and project director on the grant, hopes that their research will solve both of those issues.

“How do you optimize the level of technology needed to produce grafted plants for your particular market?” Louws says. “One team will provide leadership to look into that.”

The project involves scientists from NC State University, Clemson University, Ohio State University, University of Arizona, University of Florida, Virginia Tech and the USDA Agricultural Research Service Horticultural Research Lab in Florida.

Findings from the team’s research will result in an online decision support system, designed to help nurseries determine the best methods for propagating grafted rootstock. Based on the market, the system will help nursery owners decide which would be more profitable—grafting by manual labor or automated robots. Several large European nurseries use robots to graft plants, but they can be expensive. Is the expense worth the market? The team hopes the decision support system will answer that question.

Working in the nursery, the team will measure the effectiveness of different technologies for grafting, propagating and storing grafted rootstock. Although several innovative grafting and cutting propagation methods have been developed in the last several years, many have not yet been proven for large scale production. Scientists will test these methods to ensure that they will make the most efficient use of labor and money.

Key to success of a grafting enterprise is disease-free rootstock. Because diseases can often exist in the seed, nursery owners must take precautions to ensure that they are not selling grafted stock with pre-existing pathogens.

“What are the most important things the nursery owner needs to consider to prevent the spread of disease during the grafting process?” says Louws. “After gathering and relaying the research that has already been done on that question, we’ll identify gaps and do research to close those gaps.”

The next step is to ensure the use of grafted plants will benefit farmers. Scientists will determine some of the strongest and most disease-resistant rootstock and explore ways that farmers can manage soil-borne pathogens that cause plant diseases such as wilts and crown rot. Improving fruit quality is also an important priority. To look at issues more closely, the research team will divide into three working groups—cucurbits, tomatoes and post harvest.

“Certain rootstocks require less fertilizer and water, so they would require changes in the management systems,” Louws says. The teams will also assess rootstocks for market quality, including taste, texture and sugar content.

Researchers will work hand in hand with both conventional and organic nurserymen and growers to ensure that findings will yield results that be profitable and will present them with new opportunities.

“We want to help people know their options and determine what will work best for the market,” says Louws. “We want to make sure that nurseries are not spending too much money on too much technology. It’s about getting the best use of the technology for a profit and the teams are organized to research the best ways to use grafted plants in open field production systems.”

Written by: Rosemary Hallberg, Communication Specialist, Southern Region IPM Center, 919-513-8182 or rhallberg@sripmc.org

Date: February 16, 2012