1. North Dakota State University, Department of Plant Sciences, P.O. Box 6050, Department 7670, Fargo, ND, 58105, U.S.A.
2. International Islamic University Malaysia, Biotechnology Engineering, Gombak, Selangor, Malaysia.
3. Corresponding author. Phone: (701) 231-7737. Fax: (701) 231-8474. E-mail: senay.simsek@ndsu.edu