1. Department of Plant Breeding and Seed Production, University of Warmia and Mazury in Olsztyn, pl. Łódzki 3, 10-727 Olsztyn, Poland.
2. Center for Analytical Chemistry, Department for Agrobiotechnology, IFA-Tulln, University of Natural Resources and Applied Life Sciences in Vienna, Konrad-Lorenz-Str. 20, 3430 Tulln, Austria.
3. Corresponding author. Phone: +43-2272-66280-408. Fax: +43-2272-66280-403. E-mail: wolfgang.kandler@boku.ac.at
4. Department of Chemistry, Poznań University of Life Sciences, ul. Wojska Polskiego 75, 60-625 Poznań, Poland.