"Hazelnut (Corylus avellana L.) belongs to the family and is a popular tree nut worldwide, mainly distributed in the coasts of the Black Sea region of Turkey, southern Europe (Italy, Spain, Portugal, and France), and in some areas of the United States (Oregon and Washington). Hazelnut is also cultivated in some other countries such as New Zealand, China, Azerbaijan, Chile, Iran, and Georgia, among others. Turkey is the world’s largest producer of hazelnuts, contributing ∼74% to the total global production, followed by Italy (∼16%), the United States (∼4%), and Spain (∼3%). Other countries contribute ∼3% to the total production ... Hazelnut is, therefore, the most popular tree nut in Europe. Several commercial hazelnut varieties are available ..."