**4. Conclusions**

The data from this pilot study show differences in nutrient profiles depending on the varieties. The observed variations in nutrient composition were independent of growth conditions and climate, which were identical for all hazelnut varieties, as well as year-to-year changes. Just as growth conditions, technical processability, and resistance to pests, the nutrient content is only one of several parameters for assessing the suitability of a variety for commercial cultivation. Based on these parameters and nutrient profiles, Emoa-1, Corabel, Webb's Prize Cob, Barcelloner Zellernuss, and Merveille de Bollweiler were selected for long-term studies which are ongoing. While Corabel was the variety with the highest protein content, Webb's Prize Cob variety showed a high content of dietary fiber and Merveille de Bollweiler had the highest content of magnesium. On the other hand, Emoa-1 conceded reliably good harvests and aromatic nuts and Barcelloner Zellernuss distinguished due to a very high yield. Assessing nutrient profiles, growing behavior, and resistance to pests of these cultivars over time will allow for recommending suitable varieties, rootstocks, and cultivation systems for regional cultivation as well as changes in nutrient profiles from year to year.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/2304-8158/9/11/1596/s1, Table S1: Agronomic data of and observations for the 15 varieties cultivated in Germany.

**Author Contributions:** Conceptualization: S.L., C.D.; funding acquisition: S.L., C.D.; investigation: M.M., U.H., C.R., F.H., T.S., A.K.M.; project administration: S.L., C.D.; resources: M.M., S.L.; supervision: M.G., S.L., C.D.; validation: A.K.M., S.L., C.D.; visualization: A.K.M.; writing—original draft: A.K.M.; writing—review and editing: U.H., C.R., M.M., F.H., T.S., M.G., S.L., C.D. All authors have read and agreed to the published version of the manuscript.

**Funding:** The work of C.D. and S.L. is supported by grants from the Federal Ministry of Education and Research (01EA1411A; 01EA1708), and the German Ministry of Economics and Technology (AiF 16642 BR) via AiF (German Federation of Industrial Research Associations), FEI (Research Association of the German Food Industry), and by the Free State of Thuringia and the European Social Fund (2016 FGR 0045). The work of T.S. is supported by grants of the Federal Ministry of Education and Research (01EA1408B), the German Research Foundation (DFG) (SCHW903/10-1) and TraceAge (DFG research unit on the interactions of essential trace elements in healthy and diseased elderly, Potsdam-Berlin-Jena, FOR 2558/1).

**Acknowledgments:** We thank the staff of SYNLAB Analytics and Services Germany, Jena, especially Anne Arnold and Lars Müller, for their support to analyze tocopherols. The technical assistance of Sören Meyer from the Department of Food Chemistry for measuring minerals, trace, and ultra-trace elements is highly appreciated.

**Conflicts of Interest:** The authors declare no conflict of interest.
