Hey folks:
Keep in mind that we have an abundance of the Eastern Filbert Blight (
http://plantclinic.cornell.edu/factsheets/filbertblight.pdf) in North America. This means that it is lethal to the European Hazels (Corylus avellana) which have larger nut production in terms of size and volume. Thus, commercial production in the US was largely stunted as it tried to take a hold. The European variety lacks the cold hardiness of the American hazel (Corylus americana) and so many breeders are working on and offering hybrids as a balance to the hardness + blight resistance.
Phil Rutter interestingly showed me his hybrids that were still getting hit with blight, yet because his plants were so vigorous, he actually saw it as a partial "benefit" - the blight tended to thin out the weaker stems.
Steve