GGE biplot analysis on the performance of wheat genotype for hectolitre weight and mega environments identification in north western Ethiopia

Grain quality traits like hectolitre weight are quantitatively inherited and as a result their phenotypic performance is highly influenced by genotype, environment, and the interaction between the two. The present study was conducted in north western Ethiopia across six test locations during the 2008 and 2009 cropping seasons to study the nature of GEI on hectolitre weight of bread wheat and to classify environments based on the performance of genotypes. Randomised complete block design with three replicates was used on each site. A total of 12 advanced bread wheat lines along with standard and local checks were tested and data were analysed on hectolitre weight. Both the main effects of genotypes and environments, and their interaction significantly (P≤0.01) contributed for the observed phenotype. The environment explained 46.6 % of the total variation while GEI and genotype explained 15.6% and 10%, respectively. The first two principal components of a GGE biplot explained 67% of the variation. ETBW5344 was the most stable and near ideal genotype for regional release while ETBW5345 was the most variable genotype. The six locations were divided in to two mega environments ETBW5345 and ETBW4992 being the two best genotypes in each of the mega environments. Among the test sites Adet was the most representative and most discriminating environment while Sirinka was less desirable as a testing site for hectolitre weight. Trials across several years need to be done to firmly conclude the presence of the two mega environments.