Genotype-environment interaction and stability analysis for grain yield of winter barley in the conditions of North-East and South Bulgaria

Abstract. The aim of this study was to evaluate the grain yield of winter varieties of feed barley in different environments and to determine their stabilities. Grain yield performances were evaluated for three years (2008/2009, 2009/2010, 2010/2011) at three locations (Karnobat, General Toshevo and Sredets) in Bulgaria. The combined analysis of variance indicated that environmental factors were the most important sources affecting yield variation and these factors significantly explained 90.58% (4.40, 59.20 and 26.98% for year, location and their interactions) of the total sum of squares due to G + E + GE interaction. The average grain yield of the studied varieties of winter feed barley ranged from 5.16 t/ha (Veslets) to 5.46 t/ha (Radul). The genotypic responses to environmental changes were assessed using a linear regression coefficient (bi), the variance of the regression deviations (SDi), Lin and Binns cultivar superiority index (Pi) and GGE biplot analysis. The variety Radul was the best at combining yield stability and high mean grain yield based on most stability statistics. Variety Veslets was the most stable, but lower yielding than other studied varietie