Genetic improvement of crop performance is essential to increase yield. The aims of this paper are to present combined additive main effects and multiplicative interaction (AMMI) analysis and cluster analysis to winter wheat (Triticum aestivum L.) grain-yield data collected in preregistration trials performed over many years in an incomplete three-way genotype x location x year (GLY) classification and to demonstrate the usefulness of this procedure for studying the patterns of cultivar adaptation. The 21 genotypes were divided into three groups that were homogeneous in their pattern of genotype x location (GL) interactions. These groups of genotypes were further divided into subgroups with homogeneous genotype means. In this study 11 genotypes that were grouped in three subgroups had wide adaptability. Among them the cultivar TONACJA was identified as a good check cultivar for preregistration trials. One cultivar had narrow adaptation and nine were relatively poorly adapted. The combined AMMI and cluster analysis method proved effective for describing diverse patterns of yield response to agro-ecological conditions in locations spread across most of the Polish winter wheat growing areas.