Genotype by environment interactions can have critical impact on the performance of cultivars when evaluated in diverse agronomic locations. One of the goals of the CIMMYT tropical lowland maize breeding program is to release maize inbred lines that perform (in hybrid combination) better than the local check of a given location under good agronomic conditions (sufficient irrigation, fertilization and pest control) and at least as well as the local check under poor agronomic conditions (drought, low-nitrogen and higher disease incidence). In this study, stability analyses were utilized to make head to head comparisons between experimental Quality Protein Maize (QPM) inbred lines and the best high yielding check lines as evaluated in hybrid combination in international yield trials. Reliability estimates, two commonly used stability parameters and Additive Main effect and Multiplicative Interaction (AMMI) models were used to evaluate yield performance and endosperm modification scores. Results will be presented.