A plethora of pears
Repository’s mission is to collect, conserve, characterize, and distribute.
Left to right: Joseph Postman's choice pears ranks are Devoe, the Asian pear Hosui, Ayers, Russet Bartlett, and Rousselet. Top inset is Summer Blood Birne, lower inset is Klemintinka.
Four pear cultivars—Bartlett, d’Anjou, Bosc, and Comice—dominate supermarket shelves across the United States, and they’re great pears. But do they deserve 95 percent of the market?
“There are easily more than a hundred varieties with fruit quality as good as or better than those in the commercial market,” says Joseph Postman.
As the curator of the National Clonal Germplasm Repository in Corvallis, Oregon, he’s in a position to know.
“I have the rare opportunity to evaluate and sample more than a thousand different edible pear varieties,” he said.
The collection includes about 800 varieties of European pears and another 100 to 150 of Asian pears, situated on eight acres, and another five-plus acres devoted to wild pear species gathered from all over the world.
The repository opened in 1981, following acts of Congress that added gene banks for clonally propagated crops to the Agricultural Research Service’s National Plant Germplasm System. There are now about 30 USDA germplasm conservation facilities to assure the survival of diverse populations of grains, oil seeds, vegetables, and fruit that otherwise might be lost by the wayside as growers concentrate on production of fewer varieties.
The banks are also collection points for wild relatives
of domestic cultivars. Sometimes, private breeding programs, or breeding programs at universities, are discontinued, and some of that plant material finds its way into the bank.
Postman has been at the Corvallis repository from day one. He came to the repository as a plant pathologist and technician doing virus indexing and plant cleanup when the repository was first operated jointly with Oregon State University. In 1987, Postman, along with the rest of the repository’s employees, shifted to the USDA’s Agricultural Research Service.
Gene banks are often referred to in doomsday terms. It sounds dire when people like Bill Gates and Warren Buffett invest millions of their dollars to store plant seeds and shoots inside a vault carved out of a frozen mountain on an island in Norway. If an asteroid hits the earth, whoever survives will have the resources to start over. That’s the idea.
A library for living plants
For Postman, it’s a lot less exotic than that. As curator, he says, “I’m a librarian in charge of a living plant collection.”
Not only does he have the trees growing as single-tree specimens, he has them described and organized, library fashion, on the repository’s Web site, www.ars. usda.gov/pwa/corvallis/ncgr. The repository, as the name says, houses clonally propagated plants—and that includes blueberries, strawberries, brambles, hazelnuts, some minor fruits such as medlars and quince, as well as some nonfruit crops like hops and mint.
While often thought of as a resource mostly for plant breeders, Postman noted that there are few U.S. pear breeding programs. “Richard Bell [the pear breeder at the USDA’s Appalachian Research Center at Kearneysville, West Virginia] is my major stakeholder,” he said.
But nurseries look for new offerings. They search through the repository’s catalogue, as do farm marketers looking for different varieties of pears that they can offer at their farms or at farmers’ markets. Organic growers look for pears that are pest resistant.
The repository can supply wood for grafting, but in limited quantities, and serves mostly as a resource of last resort. The system is meant to support research and education objectives, not home gardeners. If a tree is commercially available from a nursery, the Web site offers some help in finding it. “Over the years, Seckel pear has been the most requested scion wood from our pear collection,” Postman said.
The repository has four distinct purposes—to collect, conserve, characterize,
and distribute. As well as the orchard itself—collecting and conserving—the repository stores plant and seed information in a Resources Information Network.
On the collecting side, Postman participates in expeditions to other countries to collect seed and plant samples from wherever pears originated or have been grown a long time. Pears are among the oldest cultivated fruits in the world.
In the information retrieval system, pears are characterized by fruit qualities like early or late ripening, large or small fruit, and flesh and skin color. Trees are characterized by compactness of habit, cold hardiness, chill requirements, and other qualities. Pears are also grouped by special uses—do they make good cider (perry), are they graft compatible with quince, do they have resistance to fireblight, mildew, leaf spot, psylla, or scab?
The varieties are also described in sensory terms. Are they firm or soft, melting? Do they have stone cells, are they smooth or russeted? What’s the flavor like? What’s their shape?
They are also grouped by country of origin.
Postman is also working with colleagues on DNA fingerprinting, so that the genetic blueprint of each variety will be available to help growers and nurseries accurately name the pears they have.
The Web site is a gold mine of pear information. Want to know the history of Old Home x Farmingdale rootstocks? Want to see a picture of the Endicott pear, the oldest fruit tree in North America? Looking for pictures to help identify your pear tree? The full text of Pears of New York, by U.P. Hedrick, is on the Web site, complete with original illustrations of 80 varieties. The USDA’s collection of pomological watercolor prints is linked there, too.
The actual work of maintaining the trees is not demanding. “We don’t do a lot of spraying,” Postman said. “We’re not harvesting the fruit, just the scion wood,” he said. In recent years, one lime-sulfur spray per season has been about it. The Corvallis area is not plagued by fireblight.
The repository only occasionally hosts organized fruit showcases or tastings, but visitors are welcome. And if a fruit is ripe, it’s eligible for tasting, and growers can see what the fruit is like. Pears, Postman said, are diverse in shape, color, and size, and also in ripening period. The earliest ones ripen in June, while later ones ripen in November.
For someone with a farm market, a properly planned pear orchard could deliver a distinctly different fruit each week for six months of the year.