UC Davis researchers breeding new strawberry varieties
David Castellon
PRUNEDALE – If you're a fan of strawberries, chances are your primary considerations are size; whether the fruit has rich, red color; and how it tastes.
But for Tom Ramirez and other strawberry growers, that's just the start of what goes into deciding which varieties of the fruit to grow.
There's whether the fruit is resistant to the diseases and insects that threaten some strawberry crops, how firm the fruit is so it can survive being packaged and shipped, when the strawberry plants begin producing their fruit and how easy it is to pick the fruit.
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The latter is rarely considered by consumers, but it's crucial to growers, said Ramirez, who runs the 70-acre Elkhorn Berry Farms here.
Besides growing his own strawberries, he has provided a quarter acre of his farm as a test-growing site for potential new varieties of strawberries being developed by researchers for the University of California, Davis Strawberry Breeding Program.
Currently, 68 different varieties are being grown here, and members of the UC Davis breeding program arrived Wednesday to look at the progress of the fruit and get input from Ramirez and his workers.
And, of course, they were there to taste some of the fruits of their labor, among them Steven J. Knapp, a geneticist who late last year was appointed head of the Strawberry Breeding Program.
"It's better. It's aromatic," he said after biting into one strawberry, which had a peachy flavor he liked.
Later, he noted how thick the cover of green leaves was growing on another variety, which he later explained could be a problem for harvesting crews who might have to rummage through the leaves to find the fruit below to pick, slowing their harvesting time.
That's a particularly important consideration these days, said Ramirez, noting that farm labor has become increasingly hard to get in this region in the past five years, and with California's minimum wage going up, farmers will have to pay more for that labor.
As such, farmers will be looking to avoid anything that slows strawberry harvesting, so they'll more likely prefer plants with light foliage if the yield and fruit quality are good.
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These test variates were created by cross breeding the flowers from different strawberry varieties to try to combine the best element of each into the seeds that make new plants, Knapp said.
None of these test varieties have names yet, which isn't surprising, because the Davis researchers started with 20,000 test varieties and, through initial plantings and research, whittled them down to the 68 here, Knapp said.
And once the research is done in Prunedale and at four additional test grow sites in Salinas, Oxnard and Santa Maria, the best prospects will be planted next year in "strip trials" at larger fields for more testing.
After that, by late next year Davis officials could announce one or more new variates of strawberries that the breeding program will produce and make available for sale to commercial growers, Knapp said.
In fact, the program has been averaging one new variety per year since 1968, and while those variates are primarily developed with California commercial growers in mind, Knapp said the estimated 1.1 billion plants – or "clones" – sold annually go to about 80 countries.
Currently, eight or nine varieties of strawberries are grown commercially in large numbers in the Monterey Bay region, along with another eight or nine proprietary varieties bred by some of the larger berry produces, he said.
As for why new varieties are needed, Rick Tomlinson, president of the California Strawberry Commission, who joined Knapp and the other researchers on their visit Wednesday to the Prunedale grow site, said it's not just being competitive in the marketplace that's driving this.
For example, a lot of the research is being driven by the need to make the fruit more resistant to disease, damaging insects and drought. And further breeding is needed to ensure that resistance doesn't come at a cost of taste, size, yields and longevity, he said.