This isn’t always a simple procedure because, just as with humans, offspring may not resemble their parents. If the offspring, which gets half its DNA from the wild relative parent, only inherits some of the genes necessary for a desired trait, it won’t benefit from it. And of course, the plant has to continue to produce lots of tasty vegetables as well. This process, called pre-breeding, can often take eight to 10 years or longer, just to get to the point where a seed company could take over.
“For a seed company, a long-term project is two to three years,” says Philipp Simon, a USDA carrot breeder who leads the Global Crop Diversity Trust’s wild carrot project. “A seed company doesn’t want to work with a wild carrot relative—that would take forever from their frame of reference.” So pre-breeding, which creates the materials for mainstream breeders to use in their work, usually happens at universities and public institutes like the World Vegetable Center.
Eighty-nine new wild relatives of eggplant have been collected and will be grown at the center over the coming years. But in parallel, while those efforts get off the ground, the center’s collaborators at the University of Valencia in Spain have started to forge ahead using wild eggplant relatives that were already in gene banks. Geneticist Jaime Prohens and his group there have drawn on samples from Asia and Africa, as well as two distantly related American relatives, over the past several years. “This means crossing eggplant with a species that separated about 20 million years ago,” says Prohens—an exciting, if difficult, task because they have very different genes.
To its surprise, Prohens’ team has already managed to get fertile hybrid plants from many crosses and, with some lab work, coaxed seeds from a few others. These will mix eggplant genes in new ways, and the most interesting specimens have arrived at the World Vegetable Center, where they will be evaluated for resistance to pests.
In the greenhouse, Rakha lifts the leaf of a potted cabbage plant to reveal hundreds of tiny whiteflies, which suck the sap out of eggplant leaves. The center keeps thriving populations of common crop pests like whiteflies in a special greenhouse for such experiments. Rakha and his colleagues hope that the new, hybrid plants will stand up to their scourge.
As researchers record what all these fresh infusions into the domesticated eggplant’s gene pool do in the field, the information will be entered into a database that anyone around the world can access, says Benjamin Kilian, the manager for the project at the World Crop Diversity Trust. “All pre-breeding data will be freely available,” he says.
An Open Vault
How swiftly might insights from the wild relatives project hit grocery store shelves? That depends on what researchers find and how seed companies decide to make use of the breeding material. Five seed companies are collaborating with the World Vegetable Center on the eggplant work, testing the new plants in their own fields. “These companies might select [the] most promising materials for their own breeding,” says Kilian, which would accelerate the eggplants’ arrival in stores. So far, no eggplant from the project has reached the consumer phase.
In just two years, the current funding for the Crop Wild Relatives project will end; partners and other stakeholders will have selected the most promising pre-bred materials and integrated them into their breeding pipelines by then. But the project’s legacy will remain in the seed banks of the world.
Van Zonnefeld visits World Vegetable Center seed bank curators Yung-kuang Huang and Tien-hor Wu—“There are not many people who have seen more eggplant diversity than Mr. Wu,” Van Zonnefeld says by way of introduction—and together the three scientists go down white corridors and up a flight of stairs to the door of a vault. Inside, it’s a frigid 41 degrees Fahrenheit. Heavy rolling shelving units can be pushed apart to reveal thousands of little silver envelopes, each one containing the legacy of a plant. “This represents a part of the history of man and plant,” says Van Zonnefeld. “It’s one of the—if not the largest—public international gene bank of vegetable germplasm.” A thermostat senses the heat of our bodies and industrial fans slam on, sending a wave of cold air over the room and its precious contents, which anyone willing to do the import paperwork—seed company employee, scientist, interested gardener—can request.
Wild relatives are not immune to troubles, as construction projects and other disturbances frequently threaten to encroach on their habitats. Still, they can be found in the most unlikely of places––it just takes a little practice to recognize them. Phillip Simon, the carrot breeder, has collected wild carrots by the roadside in Turkey, Tunisia, Uzbekistan, and Turkmenistan.
“My first collecting trip was to what was at the time the USSR in 1989,” he says. In the United States Department of Agriculture’s gene bank are purple carrot seeds he collected near Homs, Syria, many years ago, which may not exist there anymore. The USDA has funding available for collecting missions focused on wild relatives, although not many scientists realize it, Simons says. And within the U.S., there are amateur groups that go out collecting as well, on the hunt for wild garlic and onion and carrots—the global seed safari, on a much smaller scale.
On the other side of the world in Taiwan, Van Zonnefeld spotted a mung bean relative in the wild recently, and he brought it back to his office to press it. Now he carefully lifts a sheet of newspaper to reveal the delicate curl of the dried plant. Its unassuming yellow flowers not yet gone to seed, they resemble those of their much more famous cousin, a crop eaten by millions. For him, it represents the promise of a better future.
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