The Art of Tomato Breeding

As the fog lifts from Sunol Valley, stark early-summer sun illuminates rows of flowering plants: tomatoes, safflower, chrysanthemum, and white borage. A Bay breeze pulls butterflies and bees into the tangle of blossoms as Fred Hempel slides loops of twine over tender green leaves to trellis his tomatoes upright in the wind.

Now, the work shows in his hands: Dark-green resin pressed under nails and worn into cuticles, fingers firmed from years of careful pulling and lifting of the tiny cherries and stem-heavy slicers.

And it stays in the nostrils—the sweet scent of resin, ripe tomatoes separated for their progeny, the aroma of gel sacks slowly loosened from the seed. These sensations remain throughout the rainy season, giving birth to dreams of vine and musky leaf.

From his six-acre Baia Nicchia Farm in the Sunol Agriculture Park in eastern Alameda County, Hempel develops original varieties of tomatoes—organic strains that cross hybrids with heirlooms. (A hybrid is a genetic cross of two different varieties. An heirloom is a pure variety grown from seed that has been passed down for several generations.) In addition to breeding tomatoes, Hempel grows unusual peppers, winter squash, yuzu leaves, highland kale (aka Ethiopian kale), and numerous varieties of edible flowers. He sells the vegetables and herbs to Bay Area restaurants like Lalime’s and Boulevard, and he also sells seeds to gardeners and growers.

Tomato breeding is a process of years—often five to seven per cross—in which a mix of traits is developed from two different tomato varieties. As Hempel puts it: “To cross two tomato varieties you place pollen from one variety onto the female structure of another. Specifically, you remove a pollen-producing anther from one plant and dust pollen from that anther onto the pistil of another plant. The pistil is a structure connected to the ovary, which becomes the fruit. The ovary/fruit produces the embryos, which are contained in the seeds.”

Hempel has learned that he shouldn’t just trust his heart when it comes to the tomatoes he’s developing. He’s created a membership opportunity for collaboration with growers and test plots to help assess his varieties in diverse growing situations across the United States and Mexico. This year, he’s experimenting with 55 cherry and 30 zebra (striped) crosses, honing each by taking out the weak or less-than-perfect flavor profiles.

The goal is a tomato with the right balance of acidity, sweetness, and indescribable savor—one that makes tasters kick their feet into the dirt as tender flesh hits their tongues. But beyond taste, there are other factors that determine whether a tomato cross will make it out of a breeder’s garden: Can it resist diseases and pests? Is it robust enough to handle weather changes? Will it survive the trip from farm to market and hold up well on the shelf? In order for small organic farmers to flourish, they need robust, disease resistant, productive tomatoes.

One new hybrid cross Hempel is developing—a yet-to-be-named red cherry tomato with yellow stripes—offers a sublime balance of sweetness and acidity. Combining hybrids like Sungold with heirlooms can yield a vigorous and delectable tomato.

One of Hempel’s most successful tomatoes is Orange Jazz. Developed from four different heirloom parents and released six years ago, it’s a great-tasting orange beefsteak fruit with green stripes.

Growing Hempel’s tomatoes in your home garden might start with a winter visit to any shop (or website) offering Johnny’s Selected Seeds or A.P. Whaley Seed Company products. But if you’re buying online, you might want to visit Hempel’s own online seed store, Artisan Seeds (growartisan.com). At that site, Hempel also announces his Hands-on Tomato Growing and Breeding Workshops held at his farm at the Sunol Ag Park.

Click here to read about how chef Anthony Paone cooks with Hempel’s tomatoes.

Catching the Cosmic Eclipse

I first met Brad Gates of Fairfield’s Wild Boar Farms at the Lake Merritt farmers’ market 10 years ago when I was working as an intern at Tip Top Farm. We were at our market stand selling our Sungold, Black Plum, and Cherokee Purple when Gates—weathered from his farm activity, Delta winds, and glittery dry heat of July—rushed over to our table. His resin-infiltrated hands cradled a mix of large and small striped tomatoes ranging from green to yellow to purple. We took five of these treasures back to our dusty outdoor farm kitchen, dressed them in olive oil and sea salt, and sized up the competition. The sour smack balanced by equally weighty sweetness was interrupted by tongue-curling heady musk and umami. Clearly our farm sold the best popular heirlooms and hybrids, but the tomatoes Gates brought us were something else, something incomparable. These were varieties that incorporated wild tomato strains and displayed a mélange of color ripening on the thin surface of each tomato. They were unseen in the Bay Area and national markets before breeders like Gates and Hempel started increasing the genetic pool with strange, beautiful, and delicious flavor bombs.

“Brad is a selector. He has a strong sense of selection, and the quality of his flavors are on target with the best of what he’s grown,” Hempel says of Gates’s work as a breeder. The mutual respect between the two becomes apparent when I visit Gates at his plot in the northern end of Suisun Valley, edging Napa. He is in the process of developing a cross with one of Hempel’s varieties, Purple Bumblebee, and as I hold the ripe fruit in my hands, Gates asks me to bring it to Hempel as a gift. I wonder if it’s a way of showing off that in early June, the Wild Boar tomatoes are already ripe, or maybe to show appreciation for Hempel’s skill.

Gates no longer sells at the farmers’ markets. He’s shifted his strategies in an effort to have greater impact on the eating and growing habits of his customers and to better sustain himself in the hard business of food production. “Tomato slave” is how he refers to himself in his early years growing tomatoes for the farmers’ markets. Wild Boar Farm is now fully geared toward wholesale nursery production and seed breeding. The seeds are available from Baker Creek Heirloom Seeds or Wild Boar’s online store (wildboarfarms.com). Orchard Nursery in Lafayette and Alden Lane in Livermore are among the nearby nurseries that sell his seedlings.

Widely known for his multicolored crosses such as the Pink Berkeley Tie-Dye and cherry tomatoes like Barry’s Crazy Cherry, Gates recently has been concentrating on adding several anthocyanin-packed tomato varieties to his list with new releases like the Cosmic Eclipse. The deep blue, purple, black of anthocyanin (a pigment and antioxidant) shows in the skin as streaks, bangs near the stem, or full covering, as well as in marks in the flesh, depending on the variety and the fruit’s sun exposure. Gates says tomatoes manifest both “gifts and curses from nature,” but purposefully crossing heirloom tomatoes with wild and hybrid strains and then picking out winners not only results in disease resistance, unique flavor, and longer shelf life, but the tomatoes also contain higher levels of antioxidants like anthocyanin and lycopene. When Baker Creek tested Gates’s anthocyanin line of tomatoes, they averaged four times the lycopene content found in more traditional tomato varieties.

Taste the rainbow at Tomatotopia

Fred Hempel and Brad Gates will be at Oakland’s Jack London Square on Sunday, September 25, 2016, noon to 5pm, with plenty of their tomatoes—older varieties, plus some so new that they don’t yet have names. At Tomatotopia, you might look forward to Fred Hempel’s Orange Jazz, Blush, Maglia Rosa Cherry, and the yet-to-be-named new red cherry with yellow stripes. He’ll have examples from among the 85 crosses he’s testing this year. Brad Gates might bring tomatoes with names like Pork Chop, Haley’s Purple Comet, Black Beauty, and Michael Pollan. It’s hard to say what will be ripe and plentiful, but you can be sure you’ll taste some of the anthocyanin-rich varieties. Since both breeders develop an average of a half dozen new varieties each year, tasters will surely bask in the full smack of a fragrant rainbow of original tomatoes.

Gabrielle Myers is a writer, teacher, and chef. Her memoir, Hive-Mind, details her growth and confrontation of tragedy on a small organic farm run by a female farmer. She is a professor of English at San Joaquin Delta College