Plant Resistant Cultivars
The hazelnut breeding program at Oregon State University directed by 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). Three recent releases ('Lewis', 'Clark', and 'Sacajawea') have quantitative resistance, while 'Santiam', 'Yamhill' and 'Jefferson' have complete resistance 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.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 to the strain of EFB currently found in Oregon, 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', complete 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
Immune
Ennis
(++++++)Barcelona
(++++)Clark
(++)Gasaway
(---)Daviana
(++++++)Butler
(++++)Lewis
(++)Santiam
(---)DuChilly
(++++++)Hall's Giant
(+++)
Yamhill
(---)TGdL
(++++++)Willamette
(+++)Sacajawea
(+)Jefferson
(---)Tonda Romana
(++++++)
VR series
(---)Casina
(+++++)
Gamma
(---)Negret
(+++++)
Gem
(+)Delta
(---)Dundee
(++++++)
TdG
(+)Epsilon
(---)Newburg
(++++++)
Eta
(---)
Theta
(---)
Zeta
(---)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.
--- = Immune, does not become diseased. Type cultivar Gasaway.
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