North Carolina State University researchers came to similar conclusions after a threeyear field trial, noting that, “Because grafting allows for rapid deployment of host resistance into a diversity of production systems, this technology will be important for growers that wish to manage soil borne diseases without the use of chemical fumigants.”
For specialty heirloom tomato producers and high-yield hothouse producers, grafting already is financially feasible and widely practiced.
A lot more work is needed to make grafting economically viable on a large scale in Florida fields, says Monica Ozores- Hampton, a vegetable specialist and assistant professor with IFAS in Immokalee.
With about 40,000 acres of tomatoes, Florida has a lot at stake, along with California, the other major U.S. tomato-producer.
More than a dozen other states grow smaller amounts of tomatoes.
“We are making progress,” Ozores- Hampton says of basic research. “But grafting is very expensive.”
Poklemba says he and other Florida growers support the ongoing research on grafting in part because as soil fumigants such as methyl bromide are removed from the toolbox, the costs to grow tomatoes and other crops rise. And grafted plants become more competitive.
If fewer but hardier grafted plants boost the yield and the expense of soil fumigants are excluded, then the equation shifts more toward grafting despite the higher upfront costs.
Poklemba has grafted some tomato plants to help researchers, such as UF’s Ozores- Hampton and her colleague Xin Zhao, who focuses more on north Florida. Zhao notes in a Tomato Institute Proceedings report in 2008 that good healthy scions united with vigorous rootstocks can produce more and better tomatoes under the right conditions.
Grafting is a way to potentially boost healthful benefits in the crop, such as raising the level of nutrients or antioxidants, and that could provide a marketing edge for producers.
Some growers say they have not seen any increase in yield with grafts, however, and report that undesirable traits can sometimes reduce the quality of the harvest.
Watermelon growers, for example, have reported that the squash and gourd rootstocks that are resistant to soil pests can impart squashlike characteristics to the melons. Undesirable traits may include a tougher rind, and the flesh of the melon may be off-color, or less than bright red.