_____________________________________________________________________________________________________ *Corresponding author: E-mail: habtejifar@gmail.com; Journal of Experimental Agriculture International 35(5): 1-13, 2019; Article no.JEAI.48459 ISSN: 2457-0591 (Past name: American Journal of Experimental Agriculture, Past ISSN: 2231-0606) Genotype-by-Environment Interaction and Stability Analysis in Grain Yield of Improved Tef (Eragrostis tef) Varieties Evaluated in Ethiopia Habte Jifar 1* , Kebebew Assefa 2 , Kassahun Tesfaye 3 , Kifle Dagne 4 and Zerihun Tadele 5,6 1 Ethiopian Institute of Agricultural Research, Holetta Agricultural Research Center, P.O.Box 31, Holetta, Ethiopia. 2 Ethiopian Institute of Agricultural Research, Debre Zeit Agricultural Research Center, P.O.Box 32, Debre Zeit, Ethiopia. 3 Institute of Biotechnology, Addis Ababa University, P.O.Box 32853, Addis Ababa, Ethiopia. 4 Department of Microbial Cellular and Molecular Biology, Addis Ababa University, P.O.Box 1076, Addis Ababa, Ethiopia. 5 Institute of Plant Sciences, University of Bern, Altenbergrain 21, 3013 Bern, Switzerland. 6 Center for Development and Environment (CDE), University of Bern, 3012 Bern, Switzerland. Authors’ contributions This work was carried out in collaboration among all authors. Author HJ designed the study, executed the experiment, performed the statistical analysis and wrote the first draft of the manuscript. Authors KA, KT, KD and ZT supervised the study. All authors read and approved the final manuscript. Article Information DOI: 10.9734/JEAI/2019/v35i530214 Editor(s): (1) Dr. Slawomir Borek, Professor, Department of Plant Physiology, Adam Mickiewicz University, Poland. Reviewers: (1) Schirley Costalonga, Universidade Federal do Espírito Santo, Brazil. (2) Dr. R. K. Lal, Central Institute of Medicinal and Aromatic Plants, Lucknow UP 226015, India. Complete Peer review History: http://www.sdiarticle3.com/review-history/48459 Received 25 January 2019 Accepted 15 April 2019 Published 07 May 2019 ABSTRACT Aims: To assess the magnitude of genotype by environment interaction; possible existence of different mega-environments; and discriminating ability and representativeness of the testing environments. Study Design: Randomized complete Block Design with three replications. Original Research Article