Flowering and yield of eastern filbert blight resistant hazelnut cultivars in southwestern British Columbia

Abstract

Trees of six recently released hazelnut (Corylus avellana) cultivars (Eta, Gamma, Jefferson, Sacajawea, Theta, and Yamhill) were grown at five locations in southwestern British Columbia to evaluate female receptivity and pollen shed timing, disease resistance, and nut yield. The overlap of female receptivity and pollen shed of mating-compatible cultivars equaled or exceeded that reported elsewhere. Following 4–6 yr of field growth without fungicides at sites adjoining eastern filbert blight (EFB)-infected orchards, EFB symptoms were absent from four cultivars (Eta, Gamma, Theta, Yamhill), negligible on Jefferson, and substantial on Sacajawea. Two additional potential diseases, Phomopsis sp. and Phytophthora sp., were observed on several trees at multiple farms. Yields varied by cultivar and farm, averaging 2.9 kg per tree of sixth-leaf Jefferson and 1.0 kg per tree of fourth-leaf Yamhill; the highest yield per tree observed was 9.3 kg for fifth-leaf Jefferson. These data, the first describing flowering and yield of these cultivars from operational orchards and the only such data from British Columbia, demonstrate the potential for new hazelnut cultivars even where pressure from eastern filbert blight is high. Also revealed are two potential emergent diseases for which growers need to remain vigilant.