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Extended Field Storage Tomato Varieties Offer Hope

The Tomato Magazine
February 2006

By Lisa Lieberman

One of the big challenges tomato growers struggle with each year is timing their plantings just right so that at the end of the season, they are able to harvest their fields and get their tomatoes to the processors without creating a bottleneck. Bottlenecks frequently occur when they are forced to harvest too many acres at the same time.
The problem is Mother Nature doesn’t always cooperate.

“ If it’s raining, you can’t always get into the field to harvest,” notes Michele LeStrange, a University of California extension specialist. “Or, if you have cold weather followed by a hot spell, everything speeds up and is ready at one time and the grower has to figure out which fields to harvest first, second and third.”

Ideally, growers would have enough leeway so that when their tomatoes were ready to harvest, they could store them in the field for an extra week or two until they’re able to get to them, explains LeStrange, who has been conducting experiments with extended field storage (EFS) tomato varieties this past year.

More Research Needed
Although this was the first year doing the experiment—and more trials are needed over the next couple of years to come up with conclusive results—LeStrange is optimistic about the future. So far, at least, it looks like there are tomato varieties out there that have the EFS qualities being sought.

Another part of LeStrange’s experiments was to look at how much extra yield earlier plantings of tomatoes got in comparison to later planted varieties. Not surprisingly, the earlier planted varieties got higher yields, LeStrange says. Plantings on April 12 yielded 38 tons per acre, while April 27 plantings got 33.2 tons per acre and May 17 plantings yielded 21.3 tons per acre.

“ The results weren’t surprising, but the main point is that, ideally, growers want to plant, and harvest, throughout the whole season,” LeStrange says. The trick would be finding a way to plant early and then hold the tomatoes in the fields knowing the yields will be higher.

For each of the three planting, LeStrange did three different harvests. For the April 12 planting, the second harvest yielded 36.8 tons while the third harvest yielded 33.7 tons per acre. Comparing the April 27 planting, which yielded 33.2 acres on the first harvest, to the April 12 yield on the third harvest, the earlier plantings yielded the most tonnage in all cases. These results seem to corroborate LeStrange’s finding that it’s often better to plant early and harvest late than to plant later and harvest earlier.

During her field trials, LeStrange also found that the level of brix in the tomatoes at all stages of planting and harvesting remained fairly stable while the general pH increased by only one-tenth with each successive harvest.

Looked at Fruit Setting Ability
In addition to testing varieties for EFS qualities, LeStrange also looked at the ability of different varieties to set fruit during heavy heat spells. Some of the varieties which did well in the heat but did not necessarily set a lot of fruit included H 9997, Sun 6368 and U 886. Finding higher yielding varieties that have EFS and set well during the heat could ultimately help growers cut costs, LeStrange feels.

“During harvest time, canneries are running 24/7 and want to be filled to capacity, so they want tomatoes every single day to stay efficient,” the researcher points out.
“In order to satisfy their demands, a lot of growers will plant more acreage than they actually need because they know they’re going to lose some fruit to the heat. This way they end up spending more money on seed and pest management than they actually need. If they could get the right varieties that had the right acceptance among processors, they could end up saving money.”

Richard Ozminkowski, manager of agriculture research for Heinz, notes that Heinz has also been working on coming up with new EFS and heat-resistant tomato varieties.

“ This past year in California, there was a very strong heat spell in July,” Ozminkowski says, “and there was considerable yield loss in a lot of standard varieties that were out there. Because we don’t always know when heat spells are going to occur, tomatoes that have that heat-setting ability are a nice kind of insurance.”

While there are heat-setting varieties out there, the problem is not all have the right viscosity for the processors or high enough yields for the growers, Ozminkowski points out. Right now, Heinz is working on creating its own heat-setting varieties, one of which may be good for a peel-and-dice-type tomato. However, he says it may take another two to three years of testing before any of these varieties are ready to be used commercially.

Heinz Varieties Showing Promise
So far, Heinz has come out with several EFS varieties that have done well commercially, Ozminkowski says. H 9780, H 9665, H 2401 and H 9995 varieties have been some of Heinz’s top performing EFS varieties.

One of the main benefits of EFS varieties that may make growers consider planting them despite their lower yields is that they generally hold up better in the rain than some standards do, Ozminkowski says.

“ In the past couple of years we’ve had rain events in September, and what happens is that the varieties that don’t have field-storing abilities are the ones that rot very soon after it rains,” he says. “These EFS varieties give the grower the potential to let his tomatoes sit for an extra few days while he’s busy getting the more sensitive varieties out of the field.”

Although late rains are one reason to utilize EFS varieties, growers might also want to use them in areas that have high humidity, Ozminkowski adds.

“In areas in Central California where there are more humid environments, growers have to be careful of mold setting inside of dense canopies,” he points out. “Field storage varieties aren’t immune to mold, but they give you that extra bit of time to get the tomatoes off. You also have less of a problem with mold when it goes through the grading station.”

Even sunburn may become less of a problem for growers using EFS varieties since moisture is what causes sunburn in the first place, Ozminkowski observes.

Although Heinz’s EFS varieties are mostly for the late season, the processor would like to come up with EFS varieties for the mid-season as well, he adds.

“If we can bring the ability of EFS varieties into the field a little earlier, it would help because you don’t know when you’re going to get late August rains or when you might run into problems with crops bunching up,” Ozminkowski says. “Processors can run a lot of fruit but they still have limited capacity. So, if the weather doesn’t always cooperate earlier in the season, EFS is a beneficial management tool for avoiding bottlenecking.”

© 2006 Columbia Publishing

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