Blight-resistant varieties win praise from growers
By JOHN SCHMITZ
For the Capital Press
AMITY, Ore. -- Jefferson and Yamhill are emerging as two front runners as the Oregon hazelnut industry sifts through Eastern-filbert-blight-resistant cultivars developed by Oregon State University.
"I think they're both going to make it," Oregon Hazelnut Commission administrator Polly Owen said. "In general, people are feeling that both of those varieties are very good."
Owen said that the two cultivars are grown for different markets: Yamhill for kernel and Jefferson for in shell.
Jefferson has become a favorite with blight-threatened growers. Produced by Shawn Mehlenbacher's OSU breeding program, it's the first in-shell cultivar that is completely resistant to the fungus.
OSU Yamhill County Extension agent Jeff Olsen said Jefferson -- aka "007" -- was the cultivar "people were waiting for" because of its higher profit potential as an in-shell nut.
"Some people waited more patiently than others," Olsen said. "It went out as an experimental planting with a lot of (growers)."
Many of those early growers took the risk of planting Jefferson before it was officially released by OSU.
"It basically is a nice replacement for (the blight-susceptible) Barcelona," Olsen said. "In some ways it's really quite similar. It has an upright, very vigorous type of growth pattern. The tree size is not as big as Barcelona, more around 65 to 70 percent and slightly more compact."
Jefferson shines with higher accumulative nut yields than Barcelona during the early growth and harvest years, Olsen said.
One Jefferson characteristic that growers should be aware of is that it has about the same level of susceptibility to common blight as Barcelona, Olsen said. To combat the disease, young orchards are treated with copper in the fall.
Only three days separate the harvest dates of the two cultivars, with Jefferson coming on three days later.
Yamhill, which is also totally resistant to Eastern filbert blight and produces nuts about the size of Cassina, is quite distinct from Jefferson. While Jefferson's limbs are upright, Yamhill's are flatter and more spreading.
For that reason, Olsen recommends that after Yamhill trees have gone through their early growth stages the pruning should be altered to select for upright branches.
Another distinction between Yamhill and Jefferson is that Yamhill comes into harvest 10 to 15 days before Barcelona.
Yamhill's accumulative nut yield is also 10 percent higher than Barcelona's. Barcelona, which remains Oregon's flagship variety, is the benchmark for advanced selections from the OSU breeding program.