Characterisation of selected hazelnut cultivars: phenology, growing and yielding capacity, market quality and nutraceutical value

BACKGROUND: Sixteen hazelnut cultivars growing in the continental climate of Slovenia were analysed over 15 years for their phenology, growth habit, yield potential, susceptibility to hazelnut weevil and the pomological traits and phenolic content of their nuts in order to obtain a complex value of these cultivars for growers, the confectionary industry and consumers. RESULTS: Blooming occurred over an interval of 10-23 days for female (pistillate) flowers and 11-22 days for male (staminate) flowers. Nocchione, Romai, Pauetet, ID and Daria were the most productive cultivars, with a nine-year cumulative yield ranging from 31.8 to 44.7 kg per plant. Pauetet, F. Coutard, Nocchione and Segorbe were less susceptible to unfavourable weather conditions during blooming and fertilisation, in terms of maintaining acceptable yields with limited blank production. Under integrated pest management, less than 2% of the nuts of Romai, Daria, TGDL and Nocchione were affected by hazelnut weevil, compared with an average of 5.5% for the other cultivars. Daria, Pauetet and T. Giffoni performed best with regard to kernel percentage and blanching ratio. The results suggest that raw kernels are a good source of the natural antioxidants gallic acid and epicatechin. CONCLUSION: The results of this study provide direction when choosing hazelnut cultivars for planting, consuming or processing. They can be applied not only in Slovenia and nearby countries but also in other parts of central and northern European countries with similar climates and growing conditions. (C) 2011 Society of Chemical Industry