Abstract: Different varieties of flat-European hazelnuts have different contents of nutrients, especially oil content, fatty acid composition, and α-vitamin E content. This study was designed to compare the diversity of 8 flat-European hybrid varieties of hazelnuts. Oil contents were determined with Soxhlet extraction. Fatty acids were analyzed by gas chromatography and colorimetry. Cluster analysis was applied for discrimination among these varieties. The results showed that there were significant differences in the contents of nutrients among 8 varieties. The mean oil content was 56.36% ranging from 52.92% to 59.24%. Monounsaturated, polyunsaturated, and saturated fatty acids averagely accounted for 72.54%, 16.11%, and 7.85% of the total fatty acids, respectively; oleic acid, the most abundant fatty acid, represented about 72.29%. The contents of linoleic acid and oleic acid were more than 85%. α-VE content ranged from 113.42 to 285.16 μg/g. The eight varieties were clustered into four groups: varieties 4#, 5#, 6#, and 7# in group 1, 8# in group 2, 2# and 3# in group 3, and 1# in group 4. The first three principal components accounted for 43.384 % (PC1), 34.436% (PC2) and 12.606% (PC3) of the total variation, respectively.

Key words: flat-European hazelnuts, oil content, fatty acid?composition