Envision a genebank. The image that comes to mind is probably a building-sized bank vault/freezer of seeds stored somewhere underground in Norway, not a pleasant 12 acres of land filled with pear trees in Corvallis. However, the latter is Corvallis’ own pear genebank, the USDA National Clonal Germplasm Repository, located off Route 34 on OSU’s 20-acre horticulture research farm—plus another 40 acres of farmland that the USDA purchased further up the road. The repository hosts an extensive collection of fruit and nut varieties which vary in terms of their ability to withstand cold, disease, and sub-optimal soil conditions.
“We have pears and hazelnuts; many of the berry crops: strawberries, raspberries, blackberries, currents and gooseberries, cranberries,” says Postman, who decided he wanted to work at the repository after seeing it built in 1981 as a graduate student. “We’re kind of like the library that researchers and nurserymen go to find varieties or to find the parents to make new varieties. Instead of loaning out books, we distribute cuttings.”
All of the plants housed in the repository are kept for their genetic material, or germplasm. In the case of the pear, that’s the whole tree. Pears get a much more entertaining genebank than normal due to the fact that the seeds produce undesirable hybrids, explained pear curator Joseph Postman.
“You have to store it as a growing plant,” he says. “The way we store the pears is we have an orchard of pears.”
The only way to propagate certain varieties is by taking a cutting from a tree of that type and grafting it onto a healthy root system of any type of pear or even a related species.
“You have to grow it as a tree; to make new Bartlett pears, you take a piece of that tree and graft it onto the rootstock,” explains Postman. “The rootstock variety provides the root and the anchorage, and the tree that cutting came from will determine the fruit.”
The term “clonal repository” comes from this clonal – or exact – method of propagation. Hence the pear orchard, which contains more than a thousand edible pear varieties—it’s a living library of pear trees.
In exploring the bumpy grounds of the World Pear Collection via electric cart, the orchard looks at first like any other. However, each tree is different. One bears green fruit, another golden. On some, the pears are as small as the eraser on a pencil. A few of the trees are among the last of their kind in the world.
When asked his favorite varieties, Postman groans—it has to be the most-asked question of a pear curator. But he peruses the aisles of trees, eventually pausing at a shinsui—one of his favorite Asian “apple-pears,” in this case from Japan. The taste is like no other: crisp and sweet.
The pear genebank is in a real sense an important piece of heritage, collecting heirloom varieties that might otherwise disappear. Postman’s mission is to collect varieties of edible pears and wild relatives, maintain the collection, determine the characteristics of each variety, and distribute cuttings to researchers and breeders. He’s collected pears from China and Japan, along with wild pears from the Caucasus Mountains in Armenia and Georgia where the pear originated. Today, the collection has a total of about two thousand pear varieties—of those, about a thousand are named, edible varieties. This stands in stark contrast to the four types of pears typically found in grocery stores.
“I think we are missing out,” he says. “There are some really nice pears out there.”
Some local growers take advantage of the pear genebank, including Tom Denison of Denison Farms in Corvallis. Postman gives cuttings away for free—but you have to know how to use them.
“You have to be enough of a horticulturalist to know how to graft a tree,” he says.
It’s not often you get to ask a pear curator what his favorite pear is. Of the more than a thousand edible pear varieties growing at the National Clonal Germplasm Repository, the following are several of Postman’s favorites:
Aurora: “A delicious and attractive fall pear.”
Ayers: “Gorgeous red blush and very juicy.”
Bartlet–Nye Russet: “Less prone to blemishes than green Bartlett with slightly more intense flavor.”
Beurré Superfin: “One of the best half-dozen pears.”
Butirra Rosata Morettini: “A gorgeous early fall pear.”
Dana Hovey: “A favorite of Joanie Cooper, president of the Home Orchard Society.”
Devoe: “Pretty enough to pose for a still life; creamy flavor with a hint of vanilla.”
Doyenne du Comice: “A large, juicy, ripe Comice is best eaten with a spoon.”
Hosui: “My favorite Asian pear, sweet, crisp, and juicy.”
Johantorp: “In a mild Corvallis winter we can enjoy them directly off the tree in late December.”
Rousselet de Reims: “Said to have been the favorite pear of France’s King Louis XIV.”
Seckel: “One of the best pears born in America and the most requested variety at the USDA genebank.”