Shop for pears at any supermarket these days and you’ll likely find whole bins full of perfectly shaped Bartletts and blemish-free Anjous, but few other varieties.
When Joseph Postman, on the other hand, walks through his pear orchard on a warm spring afternoon, he’ll spot a Petit Muscat from 16th century France; a Devoe from upstate New York; a Hosui from Japan; a Vavilov from Russia; or perhaps even a Pyrus betulifolia from the wilds of China. Essentially, every pear tree in each row is different.
Postman is a pear curator for the U.S. Department of Agriculture’s Agricultural Research Service. The agency funds the National Clonal Germplasm Repository in Corvallis, Ore., which is a gene bank for the world’s pears. Such varieties may have little market value individually — hence the dominance of the Anjou and the Bartlett in today’s market. But this plant pathologist-turned-“gene librarian” has made it his life’s work to preserve in perpetuity the world’s genetic diversity of pears.
“To keep old heirloom varieties is important because they’re not grown as much but they still have useful traits,” Postman said. “We’re building a reserve of potential solutions for future problems. A lack of diversity is a genetic vulnerability.”
For example, a plant breeder could pair that cold-hardy Devoe with an Anjou, say, and potentially create a pear suited to withstand climate change.
Postman has worked with the gene bank since 1981, when he was fresh out of graduate school. Oregon State University was building the gene bank as he finished his degree in plant pathology; now it’s a USDA facility.
“I was studying plant pathology in fruit trees and how diseases spread via propagation,” Postman said. “I was hired to develop a program to detect which rootstocks were carrying diseases during propagation and to prevent the spread of viruses in propagation.”
These days, his job is a combination of gardener and data collector.
Gene banks such as the one in Corvallis exist across the country, largely connected to land-grant universities — even though they are now USDA-funded.
“These gene banks originally existed as research libraries. As university libraries keep collections of books that researchers need, these gene banks provide genetic material that breeders need,” Postman said.
At his library, you’ll find more than 2,000 different pear trees. There are also 800 hazelnut varieties, 150 quince varieties and hundreds of berries.
You can search these collections via a sort of “Dewey Decimal” system in an online database. But researchers are refining this system. The gene bank employs a molecular biologist whose job it is to comb pear DNA for markers that give a more precise way of looking up this information.
“He’s using DNA tools to look at the genetic fingerprint of the plant, the same tools used in police detective work. So if a strawberry commits a crime, we’ll know which variety it is,” Postman said.
Another researcher is studying alternative storage methods for genetic material, including high-tech methods like cryogenics for plant tissue.
The living collection is stored on 20 acres at OSU’s horticultural research farm and on a 40-acre parcel nearby. To propagate such often ancient varieties, the scientists here use grafting and cuttings.
Postman has traveled as far away as Armenia to tramp through wilderness searching for wild relatives of the pear.
Other items in the collection are more sentimental, such as the Endicott pear tree. It’s the oldest living fruit tree in North America, named for the Massachusetts governor who planted it around 1630. Every year members of the Endicott family request cuttings for their family reunions. Its flavor is good, but its fruit is unattractive and coarse.
Postman believes it’s all worth saving.
“When blight wiped out hazelnuts here in Oregon, or the climate changes and the varieties we had don’t grow so well any more, it’s important to have these varieties to develop new varieties that are adapted to the new conditions,” Postman said.
For more information about the National Clonal Germplasm Repository, go to http://www.ars.usda.gov/main/site_main.htm?modecode=20-72-15-00