If anything, the roots are even more vulnerable than the fruit. They lack any corky bark or peel that would protect their simple tissue from soil-borne pests. As a result, an established field of strawberries is little more than a well-advertised, all-you-can-eat buffet for almost any bug around. Verticillium wilt, anthracnose crown rot and two-spotted spider mites are just a few of the most obnoxious.
Because of all of this, strawberries are extremely expensive to produce. A recent study by the California Strawberry Commission, a growers' organization, predicted costs of more than $30,000 an acre to grow the fruit, harvest it and ship it (for comparison, lettuce is less than $10,000). This leaves farmers scrambling for any advantage to make their investment pay off.
That's where Larson and Shaw come in. Their job is to find the one plant in a million -- almost literally -- that can give farmers an edge. It might be a plant that pops out more fruit or produces higher quality berries (even with the best of the newest varieties, farmers discard up to 20% of fruit as too small, poorly colored or misshapen).
Or it might be a plant that produces exceptionally well either early or late in the season, when the prices are highest.
The search for this perfect plant begins not with any kind of modern genetic technology, but old-fashioned birds-and-bees pollination. Larson selects a pollen-bearing male flower from a plant with desirable traits and rubs it around the center of a female flower from another selected plant.
When that fruit ripens, the seeds will be collected and planted (technically, these seeds are actually achenes; they are tiny dried fruits themselves, each one containing a seed).
Each plant will be a fraternal twin of the others from the same berry, sharing many traits, though slightly different. The plants that seem most promising will be selected and planted outdoors in fields the next year.
In the field, the new plants are numbered and grouped according to their parentage. If you look closely enough you can see the resemblances and also the differences. This plant may have large, perfectly formed fruit while its sister right next to it bears strawberries that are similarly sized but more frequently misshapen.
Larson walks the fields nearly every day for the 28 weeks that make up the heart of the typical Southern California strawberry growing season, which runs from mid-November into June.
In a hand-held Allegro CX computer loaded with a spreadsheet, he scores each plant on a variety of criteria. He counts the fruit and grades it for size, shape and color. He grades the plant's "architecture" -- how the leaves and fruit are presented -- and several other factors.
"I'm looking for the drop-dead gorgeous strawberry poster child," he says.
This early on, he doesn't pay much attention to flavor. It is just too subjective and it changes from week to week, depending on weather, variety and the individual plant. Of course, there are more mundane reasons for not tasting every plant every week as well. "I do love strawberries, but I'd have to be eating thousands a day to make it meaningful," he says. "I try to take a bite whenever I can from plants I like, at least until I start feeling bloated."
At the end of the year, he'll run the spreadsheet and analyze each plant for productivity and value. Of the 13,000 or so in the initial selection, he'll pick the best to go on to the next year. This time, he'll cut shoots from the strawberry and plant those (seeds vary genetically, while propagating from plant division ensures identical clones).
The process will repeat with further winnowing each year until one plant has proved its worth to become a variety, which means that it has been patented and licensed and that growers will have to pay a small royalty to plant it. (Once the university has covered its costs, it shares the royalties with Larson and Shaw, following a complicated formula.)
This season, in addition to the new trials, there are 487 strains from last year's first selection that made the cut. There are also 160 from the year before that, as well as a few from 2002, 2001 and 2000.
One plant survived from 1999, but Larson says this year will be its last. "I had pretty high hopes for that one to become a variety, but it just doesn't look like it's going to make it."
Even after a variety has been selected, it still has to be tried out in test plots maintained by farmers at various locations throughout the state.
All told, it takes, at the bare minimum, six years to find a plant that is worthy of becoming a named variety. It frequently takes even longer. The Chandler berry, which was introduced in 1983, took seven years for Larson and Shaw's predecessors Victor Voth and Royce Bringhurst to develop. And it took Voth a decade to select Chandler's successor, the Camarosa.