The genotype × environment interaction and stability of five cotton varieties were studied during 2002-2006. The years of the investigation appeared to be as different ecological environments. The stability variances (2i and S2i) of Shukla (1972) and YSi index of Kang (1993) were calculated. It was found that
the cotton varieties tested interacted significantly with environmental conditions (years) in terms of total and September yields, boll weigt, fiber length and lint
persentage, and height of first fruit-branch. For efficient breeding of these traits, the genotypes have to test in different years. Breeding usefull stability was
observed for all studed traits, with a significant genotype -by-environment interaction. The variety Avangard-264 had a superior combination of yield and
stability simultaneously and fiber length and stability; the variety Darmi – of fibre lint percentage and stability. The varieties containing G. barbadense L.
germplasm, responsible for their longer fibre, because of their high stability by some traits with significant genotype × environment interaction, are
recommended as very valuable in cotton breeding programs.