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', 'PollyO' 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.
Resistant selections are available from various nurseries. A list of these nurseries can be found at the Nut Growers Society 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 et al 2022). 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'.
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 |
Thompson |
||
|
|
|||
|
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.