Biplot analysis of genotype by environment interaction for barley yield in Iran

Cultivar evaluation and mega-environment identification are the most important objectives of multienvironment trials (MET). The objective of this study was to explore the effect of genotype and genotype X environment interaction on the grain yield of 19 barley (Hordeum vulgare L.) genotypes via GGE (genotype plus genotype X environment) biplot methodology. Experiments were conducted using a randomized complete block design with four replications for 3 yr at 10 locations. The biplot analysis identified three barley mega-environments in Iran. The first mega-environment contained locations Khoy, Mashhad, Miandoab, Karaj, and Nyshabour, where genotype Bahtim7-D1/79-,A,40762 was the winner, the second mega-environment contained locations Tabriz, Hamedan, Ardabil, and Arak, where genotype Walfajre[W1-229] was the winner. The location of Zanjan made up the other mega-environment, with 73-M4-30 as the winner. Genotypes Bahtim7-Dln9-w4O762 and Walfajre/WI-2291 had the highest mean yield and genotype K-201/3-2 had the poorest mean yield. The estimated relative yield of genotypes at Karaj station shows that genotype Bahtim7-D1/79-w40762 had the highest yield and genotype Owb70173-2H-OH had the poorest. The performances of genotypes Star/Alger and K-201/3-2 were highly variable, whereas genotypes Cossak/Gerhel/Harmal and Toji"S"/Robur were highly stable. The results of this study indicate the possibility of improving progress from selections under diverse location conditions by applying the GGL (genotype plus genotype X location) biplot methodology.