Hazelnut released by S. Mehlenbacher from Oregon State University with Gassaway resistance to Eastern Filbert Blight (EFB). A high yielding cultivar for the kernel market. A cross of OSU 296.082 x VR 8-32 made in 1990. OSU 296.082 is a seedling from a cross of OSU 17.068 (= Barcelona x Tombul Ghiaghli) x Willamette, and VR 8-32 is from a cross of the Sicilian cultivar Montebello x Gassaway. Compared to Barcelona, Yamhill is a smaller tree with higher nut yields per tree and a much higher yield efficiency. Nuts of Yamhill are smaller (2.3 g) than those of Barcelona (3.8 g) and have a higher percent kernel (49% vs 43%). Nuts fall free of the husk at maturity and can be mechanically harvested about 10 days earlier than Barcelona. The kernels fill the nuts well even with a heavy crop. Raw kernels are attractive, having little fiber on their light brown pellicles. Blanching ratings are equal to Barcelona, indicating that about half ot the pellicle is removed by dry heat. Kernel quality is suitable for many end uses, and it competitive with kernels imported from Turkey. 'Yamhill' has complete resistance to eastern filbert blight conferred by a dominant allele from 'Gasaway', and has incompatibility alleles S8 and S26. 'Yamhill' was released as a public cultivar and may be propagated without restriction. The Oregon Agricultural Experiment Station announces the release of a new hazelnut (Corylus avellana L.) cultivar 'Yamhill' for the kernel market with high nut yields, early-maturing nuts, high percent kernel, very good kernel quality, resistance to bud mite (primarily Phytoptus avellanae Nal.), and complete resistance to eastern filbert blight caused by Anisogramma anomala (Peck) E. Muller.
'Yamhill' (OSU 542.102) resulted from a cross of OSU 296.082 x VR 8-32 made in 1990. OSU 296.082 is a seedling from a cross of OSU 17.068 (= 'Barcelona' x 'Tombul Ghiaghli') x 'Willamette', and VR 8-32 is from a cross of the Sicilian cultivar 'Montebello' and the obsolete pollinizer 'Gasaway'. Compared to the standard 'Barcelona', 'Yamhill' has smaller trees, higher nut yields per tree, and much higher nut yield efficiency. Nuts of 'Yamhill' are smaller (2.3 g) than those of 'Barcelona' (3.8 g) and have a higher percent kernel (49% vs. 43%). The nuts fall free of the husk at maturity and can be mechanically harvested 10 to 15 days earlier than 'Barcelona'. The kernels fill the nuts well even with a heavy crop. Raw kernels are attractive, having little fiber on their light brown pellicles. Blanching ratings are equal to 'Barcelona', indicating that about half of the pellicle is removed by dry heat. Kernel quality is suitable for many end uses, and is competitive with kernels imported from Turkey. The frequency of blanks, poorly filled nuts, and doubles is less than for 'Barcelona'. 'Yamhill' has a low frequency of moldy kernels, which was especially striking in 2005 when mold was a problem on 'Lewis' and many other genotypes. 'Yamhill' has complete resistance to eastern filbert blight, conferred by a dominant allele from 'Gasaway'.
'Yamhill' has incompatibility alleles S8 and S26. Both alleles are expressed in the stigmas, but only S8 is expressed in the pollen. Pollen shed and female receptivity occur early in the season, about with 'Barcelona'. Pollinizers that shed pollen in early midseason are recommended. We recommend one-third each of 'Gamma' (S2 S10) and 'Santiam' (S3 S15) which shed pollen early in the season and have a short shedding time. For the remaining third, a mixture of later-shedding types is recommended, of which several are suitable: 'Delta' (S1 S15), 'Epsilon' (S1 S4), 'Zeta' (S1 S1) and OSU 703.007 (S1 S3). All four have complete resistance to eastern filbert blight.