Abstract: For this study ten genotypes of spring wheat (Triticum aestivum L.) developed at three different breeding institutes were evaluated for two year at nine locations in Pakistan and Azad Jammu and Kashmir. Genotypes x location, genotype x year and genotype x location x year interactions were found highly significant (P<0.01) for number of grains per spike, grain protein % and grain yield. Relative magnitude of interaction variance components viz., 2gl, 2gy and 2gly reflected that relative performance of genotypes for grain protein percentage and grain yield was more inconsistent across the locations than years and opposite was true for number of grains per spike. Correlation amongst these characters showed positive association of number of grains per spike with grain yield, whereas grain protein percentage indicated negative associated with number grains per spike and grain yield under certain environments, however effect was inconsistent. It revealed that under appropriate agro-ecological conditions, concurrent selection for high grain yield based on number of grains per spike is possible, whereas increase in yield may reduce grain protein percentage. The results suggest that for breeding superior varieties, effect of environmental factors such as temperature, precipitation ans soil fertility and their interactions on the development of these characters and their relationships should be considered greatly in breeding programmes.