By Jerry Jackson
Vegetable grafting is undergoing rigorous study in a number of states, including Florida, in an ongoing effort by scientists to grow more and better tomatoes, melons and other crops. But the technique pioneered in Asian countries has been slow to take root in the United States and remains more of a lab subject than mainstream practice—at least in the field.
That could change in the coming years as soil fumigants are phased out or sharply curtailed and farmers look for other ways to beat old foes such as Fusarium wilt and root-knot nematodes.
Grafting—the technique of splicing the scion, or top of one plant, to the hardy rootstock of another plant—has been used successfully by citrus growers and other tree-crop producers for generations.
In countries such as Japan and Korea, grafting of squash, watermelons and other tender crops has been practiced for many decades, in part because in those countries farmland is scarce and soilborne diseases are even more of a problem than in the United States
Bob Poklemba, manager of Redi-Plants Corp., a south Florida tomato transplant producer for tomato grower Six L’s, says grafting holds promise but is still too costly to make inroads into Florida’s tomato fields. “I don’t think it has a place in our own operations right now,” Poklemba says. “We use a million plants a week. It’s just too costly to make that many plants” through grafting, he says.
A grafted tomato plant for transplanting costs about $1, he says, while regular transplants typically cost less than 5 cents per plant. But Poklemba, who’s based in Naples, quickly adds that grafting can be a viable alternative for at least some smaller tomato field operations in the Carolinas, Tennessee, Virginia and other states where soil might be infested with bacterial wilt.
Grafted plants with resistant rootstocks can make the land useable for production. Florida does not yet have a problem with bacterial wilt, Poklemba says, so there is no economic reason to spend more for grafted transplants on that basis. There are other potential benefits, though.
Benefits of grafting
Field trials in Virginia showed that the yield from tomato plants grafted with bacterial wilt-resistant rootstock was “significantly greater” than from ungrafted plants, according to a report published last fall during the 25th Annual Tomato Disease Workshop in Wimauma.
The report by researchers from the University of Florida’s Institute of Food and Agricultural Sciences and Virginia Polytechnic Institute concluded that the data show that “grafting holds promise for increasing disease resistance in tomato cultivars as well as increasing the overall productivity of tomato cultivars.”