‘Jefferson’ (OSU 703.007) was developed and evaluated at Oregon State University in Corvallis, Oregon, and was released in January 2009. This variety combines very high resistance to eastern filbert blight (EFB) caused by the fungus Anisogramma anomala (Peck) E. Müller with large nut size, good kernel quality, and high yields.
Propagation and Availability
‘Jefferson’ was released as a public variety in the United States, with no restrictions for use by growers in the United States. Trees may not be sold or given to other countries without the appropriate legal documents from Oregon State University. A licensing agreement grants Viveros Nefuen (Hijuelas, Chile) the exclusive right to propagate ‘Jefferson’ and sell trees in South America.
Pollinizers
Gamma (%) = 10
Eta (%) = 30
Theta (%) = 60
Characteristics
Nut weight (g) = 3.7
Kernel weight (g) = 1.7
Percent kernel (%) = 45
Blanch rating (1-7; 7 = doesn’t blanch) = 3.9
Nuts free of defects (%) = 76
Kernel defects (%)
Blank + brown stain = 4.4
Moldy kernels = 3.0
Shrivel = 0.9
Poor Fill = 14.2
Cumulative yield 2004-2008 (kg/tree)
Field-run (nut) = 18.9
Marketable (nut)b = 13.2
Marketable (kernel) = 6.15
Cumulative nut yield efficiency (kg/cm2) = 0.30
Tree size after 9 years
Height m (ft) = 3.33 (10.8)
Canopy spread m (ft) = 3.0 (9.8)
TCSA = 78.2
For more information, download the 'Jefferson' Hazelnut bulletin offered by Oregon State University Extension.
