UF tomato breeders work on machine-harvestable varieties

10/08/2013 12:58:00 PM
Vicky Boyd

UF tomato breeder Sam HuttonCourtesy University of FloridaUniversity of Florida tomato breeder Sam HuttonUniversity of Florida tomato breeders are working to develop varieties that can be mechanically harvested, helping growers address labor costs and availability.

Although breeder Sam Hutton, who's based at the Gulf Coast Research and Education Center, Wimauma, is excited about prototypes, he says researchers are at least a few years away from releasing commercial varieties.

He updated the industry on breeding efforts at the recent Joint Tomato Conference, Sept. 4 in Naples.

For growers such as Tony DiMare, vice president of Homestead-based DiMare Fresh Inc., these varieties can't come soon enough.

"The biggest concerns we have and why we are looking at mechanization is the current labor situation and the lack thereof," he says. "And that obviously carries a heavy cost, direct costs and indirect costs, such as workers comp, transportation and a whole slew. It's become a labor supply concern more so than the direct costs of labor."

Labor, the #1 input

The average cost to plant, grow and harvest an acre of fresh-market tomatoes in Florida is $15,000, says Monica Ozores-Hampton, an assistant professor and vegetable specialist at the Southwest Florida Research and Education Center, Immokalee. Of that, about 55 percent is just for labor, which includes staking, tying and pruning plants, and harvesting.

In Florida, tomatoes are grown on plastic-covered beds into which wooden or metal stakes have been driven. During the growing season, workers create trellises of string between the stakes and train the plants up, pruning them when necessary.

After harvest, workers must remove the stakes before the field can be prepared for the next crop. In the Homestead area, growers rely on metal stakes, which are even more difficult to remove than wooden ones used elsewhere, DiMare says.

Hutton is working to develop low-growing fresh-market tomato varieties, which set fruit that ripens during a short window. The bush-like plants wouldn't require staking or training, either.

In California, processing tomato growers rely exclusively on machines to harvest their crop.

But crossing those varieties with fresh-market ones suited to Florida isn't practical because the two types are so different, Hutton says.

“The difference is they’re picking red tomatoes – we’re going after mature greens,” he says. “They’re growing plums and we’re growing large-fruited tomatoes. There’s a major distinction. It’s much more difficult to work with a large fruited tomato than a plum.”

The Holy Grail of varieties

Breeders want a tomato with a jointless pedicel, meaning the fruit separates cleanly from the plant without a stem attached that could puncture other fruit going up a harvester conveyor.

Varieties also have to produce good yields and have good flavor.

Hutton says he thought he had some contenders last season after two trials produced promising results. But last season’s wet, cold weather promoted rough-looking, misshapen fruit that would not have been unmarketable.

“I can’t underscore the difficulty of working with this type of tomato,” Hutton says. “It was really discouraging coming out of this spring’s trials.”

But the tough conditions also yielded some other promising prototypes that warrant additional trials, he says.

The breeding effort is being funded by a U.S. Department of Agriculture Specialty Crop Research Initiative grant that runs through the 2014-15 season. In addition to Hutton, Bielinski Santos, an assistant horticulture professor, and tomato breeder Jay Scott, both at the Gulf Coast center, are involved in the project.


WEB EXTRA: Mechanical harvester nears commercialization

The commercial machines used to pick processing tomatoes and the two prototypes being developed by Ramsay Highlander Inc., Salinas, Calif., to harvest fresh-market tomatoes share only a few similarities.

Both significantly reduce the need for labor and both deposit harvested fruit in tubs trailered alongside, to name a few.

But that’s where they stop, says Frank Maconachy, president.

A processing tomato harvester typically uses a cutting bar to clip plants from the roots.

The plants are then conveyed into the harvester, where a shaker that includes large agitating fingers literally shakes the fruit from the vines.

Processors can absorb a few bruised fruit because they’re going into processed products.

“But with fresh market, you have to devine them in a gentle way,” he said.

Ramsay Highlander has been working with a large California fresh-market tomato grower-packer and drew from its experience with much-more-delicate bell peppers to develop a just such a machine.

 The prototype machine uses a vine separator to handle the product that comes up quickly. During the experimental phase, Maconachy says the vine separator removed the tomatoes so well, they added a second separator and found it was much gentler on the fruit.

The fruit then passes through a color sorter that separates greens and breakers from red fruit. The reds are diverted to a gondola that goes processing, while the greens and breakers are conveyed into a separate tub for transport to the packinghouse.

A crew of about a half dozen workers also hand sorts, removing culls and material other than tomatoes that have made it past the electronic eyes.

Even details, such as operator comfort, have been incorporated into the unit, Maconachy says. The cab is completely heated and air conditioned, and a screen hooked to cameras focused to the rear and on adjacent trailers allow the operator to monitor operations without craning his or her neck.

Maconachy says they’ve passed the beta-testing phase and are in what he described as the “gamma-testing” phase.

“We really see the end of the tunnel, and we only have very minor things we have to button up,” he says.

The next step is full production mode, “but we are always continuing to make small little tweaks to continue to improve them.”

In California where the machine has been tested, producers grow a bush-type tomato with a concentrated crown fruit set on bare soil.

Having to deal with plastic-covered beds could create a challenge, Maconachy says.

“Pieces of plastic could be an issue because they would come up the conveyors,” he says.

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