The hazelnut breeding program at Oregon State University directed by
Dr. Shawn Mehlenbacher uses the genetic diversity in the genus
Corylus to
create new cultivars for the Oregon industry. One of the major
objectives is resistance to eastern filbert blight (EFB). The cultivars 'Lewis', 'Clark', 'Gem' and 'Sacajawea' have quantitative
resistance, while 'Santiam', 'Yamhill', 'Dorris', 'Wepster', 'McDonald' and 'Jefferson' have a single dominant resistance gene
from
'Gasaway'.
Dozens of promising selections are in yield
trials, and a few are being evaluated in grower orchards. Resistant
pollinizers are also available for these new releases.
The hazelnut breeding program.
Resistant selections are available from various nurseries. A list of
these nurseries can be found at the Hazelnut Marketing Board's
web site.
Although trees with the 'Gasaway' gene are resistant, a few cankers may develop but are smaller, generally do not
have stroma and a third may heal over within 2 or 3 growing seasons
(Pscheidt unpublished). Some cankers may continue to grow each year and some may produce stroma. These trees
should be removed. Susceptibility to EFB seems to be highest in high inoculum situations the first spring after planting.
Also, these trees may be resistant to the strain of
EFB currently found in Oregon, but these trees can be infected by other
strains of EFB found in eastern North America.
OSU and USDA have assembled the best hazelnut collection in the
world.
Recent additions include seedlings from nuts collected in Turkey,
Azerbaijan, Georgia, Armenia, Russia, and the Crimea. From this
collection the breeding program continues to identify sources of EFB
resistance. In addition to 'Gasaway' and 'Zimmerman', useful resistance has been identified in Minnesota seedling OSU 408.040,
Spanish cultivar 'Ratoli', Russian selection OSU 495.072, Georgian
selection 759.010, and Serbian cultivars 'Uebov' and 'Crvenje 3/96'.
This row of trees has
highly susceptible trees on the left, resistant trees in
the middle and trees of intermediate resistance on the
right. All are infected with EFB.

Photo by Ken
Johnson, 1991.
Susceptibility of hazelnut cultivars to Eastern Filbert
Blight (Anisogramma anomala).
Susceptible
|
Intermediate
|
Resistant
|
R-Gene
|
Ennis
(++++++)
|
Barcelona
(++++)
|
Clark
(++)
|
Gasaway
(---)
|
Daviana
(++++++)
|
Butler
(++++)
|
Lewis
(++)
|
Santiam
(---)
|
DuChilly
(++++++)
|
Hall's Giant
(+++)
|
|
Yamhill
(---)
|
TGdL
(++++++)
|
Willamette
(+++)
|
Sacajawea
(+)
|
Jefferson
(---)
|
Tonda Romana
(++++++)
|
|
|
Dorris
(---)
|
Casina
(+++++)
|
|
|
Wepster
(---)
|
Negret
(+++++)
|
|
Gem
(+)
|
McDonald
(---)
|
Dundee
(++++++)
|
|
TdG
(+)
|
PollyO
(---)
|
Newburg
(++++++)
|
|
|
(---)
|
|
|
|
(---)
|
|
|
|
Gamma
(---)
|
TGdL = Tonda Gentile delle Langhe;
TdG = Tonda di Giffoni.
++++++ = Highly susceptible, long canker length, low
vigor. Type cultivar Ennis.
+++++ = Susceptible, long canker length, medium
vigor.
++++ = Intermediate susceptibility, good vigor in the
presence of EFB. Type cultivar Barcelona.
+++ = Intermediate susceptibility, but with shorter
cankers or fewer stromata than Barcelona, good vigor in the
presence of EFB.
++ = Resistant, shorter cankers and with good vigor. Type
cultivar Clark.
+ = Highly resistant, shortest cankers, can become
infected but only under very high disease pressure. Type
cultivar Tonda di Giffoni.
--- = Also highly resistant but have a single dominant resistance gene. Cankers may develop but are smaller and heal over. Type cultivar
Gasaway.