Field experiment was done for eight malt barley varieties with the aim of estimating the magnitude of genotype by environment interaction and recommend stable variety. The design was randomized complete block with three replication in 2012-2013.The combined analysis of variance showed significant differences (P<0.01) for genotype, environment and genotype by environment interaction and the environment captured 72.71% of the variation in genotype by environment interaction. According to Eberhart and Russell (1966) the genotypes G1 (Bekoji, G2 (Frie Gebs and G5 (Holker) was stable and adaptable with higher mean grain yield. while, the genotype sabini was unstable with relatively higher deviation from regression coefficient 0.911.The three principal components in the AMMI analysis showed significant difference (P<0.01 ) for the first and second principal component. The three significant principal component cumulatively explained 85.8 % of the genotype by environment interaction. The AMMI2 model gives a best model fitness 93.5 by which 6.5% was explained noise. According to the ASV, Yield stability index (YSI) and Eberhart and Russell (1966) regression model the genotype G1 (Bekoji and G2 (Frie Gebs) was stable .while the genotype G3 (sabini) was unstable across the testing environment. Generally AMMI and Eberhart and Russell (1966) models showed similar genotype ranking and stability of the malt barley genotypes and the model families can be used interchangeably.
Keywords: AMMI, Genotype by Environment Interaction, ASV, YSI