Additive main effects and multiplicative interaction analysis and clustering of environments and genotypes in malting barley

Grain yield of twenty malting barley genotypes planted in four locations over three years were used to study the effect of genotypes, environments and genotype by environment interaction. Additive main effects and multiplicative interaction (AMMI) analysis was made for yield estimation, to understand the genotype by environment (GxE) interaction patterns, clustering of environments and genotypes into homogenous subunits and to study genotypic yield stability. AMMI showed that genotypes 1, 3 and 9 among high, medium and low yielder groups, respectively provided the most stable genotypes when viewed along with the first two interaction components. The environments showed high variability both in mean yield and interaction patterns, and Da-07 and La-05 were found to be less interactive with all genotypes. Clustering of AMMI estimate values grouped genotypes into five clusters and environments into four clusters. Genotypes numbers 2, 7, 17, HB-52 and HB-12, are unique as they are grouped differently from all the rest genotypes. Ethiopia is classified into 18 major agro ecological zones and 49 subagroecological zones and it is essential to cluster similar environments and develop varieties for each target environments. Consequently the genotypes EH1609-F5.B3-10 and EH1603-F5.B1-4 were stable and high yielders across the tested agroecologies of north western Ethiopia.       Key words: Malting barley, genotype by environment (GxE) interaction, additive main effects and multiplicative interaction (AMMI), stability, clustering.