Located in eastern Anatolia, Bitlis province presents microclimatic conditions for hazelnut cultivation. This microclimatic zone results from the mild effects of Lake Van and Suphan Mountain. With native hazelnut population of 2750 da, Hizan County is surrounded by high mountains, and is a special microclimatic zone where all plantations consisting of thousands of hazelnut plants are native. Bitlis can therefore be said to be rich in wild genetic resources of hazelnut. The aim of this study was to select promising genotypes within the native hazelnut population, describe the desirable nut characteristics, and provide some chemical traits with respect to nutritional values for future breeding efforts. In this study, some nut quality characteristics, protein, ash and oil contents, and fatty acid compositions of 20 Corylus avellana L. genotypes selected from native hazelnut population of Bitlis (eastern Anatolia, Turkey) were described. The hazelnut genotypes showed nut weight in a range from 1.85 to 3.63 g; kernel weight, 0.80-1.46 g; kernel percentage, 32.26-46.11 %; shell thickness, 1.20-2.04 mm; nut length, 16.1-23.4 mm; nut width, 15.9-21.0 mm; nut thickness, 12.9-18.5 mm; kernel length, 13.0-18.7 mm; kernel width, 10.3-15.4 mm; kernel thickness, 9.4-12.8 mm; nut shape index, 0.99-1.50; kernel shape index, 0.96-1.73; shrivelled kernel, 0-10%, and double kernels, 0-6%. With respect to nutritional analyses, the hazelnuts contained oil in the range from 57.5% to 74.1%; protein, 15.7-19.2%, ash, 0.79-3.21%; palmitic acid, 4.39-8.85%; stearic acid, 1.67-3.18%; oleic acid, 73.48-81.57%; linoleic acid, 10.46-14.95%: linolenic acid, 0.02-0.34%, and myristic acid, 0.01-0.16%. All genotypes had light-brown colored kernels, and kernel flavor was "medium satisfactory" and "satisfactory". The findings revealed that some genotypes are promising in nut and kernel characteristics as well as in nutritional value for future breeding efforts. (c) 2005 Elsevier Inc. All rights reserved.