Not AvailableSUMMARY Twenty three new plant type (NPT) wheat derivatives with three checks were evaluated for grain yield and stability under timely (TSI) and late-sown irrigated environments (LSI).The experiment was conducted in six environments at two locations in 2006-07 and 2007-08. Analysis of variance of stability for grain yield through Eberhart and Russell's model and AMMI analysis revealed highly significant differences among genotypes and environments and significant genotype x environment (G x E) interaction (GEI). Highly significant mean squares due to environment + genotype x environment interactions (E + G x E) in the Eberhart and Russell model revealed that genotype interacted considerably with environmental conditions that existed under TSI and LSI condition. Further partitioning of E + G x E effects indicated that E (linear), G x E (linear) component, and pooled deviation were highly significant for grain yield. Some genotypes showed linear effects over environments, while others showed significant deviation from a linear relationship. Partitioning of G x E interaction into principal components in AMMI analysis revealed that the two interaction principal component axes accounted for 90.4% of the total GEI variation. Genotypes DL 893, DL 901, DL 966 and PBW 343 exhibited high per se performance under TSI, whereas DL 880, DL 882, DL 886, DL 892, DL 893, DL 901 and DL 927 recorded high per se performance under LSI at both locations. Based on per se performance, regression coefficient, and deviations from regression as well as AMMI analysis, genotypes DL 886, DL 901, DL 924, DL 927, DL 966 and DL 960 were found to be stable and are adaptable to both TSI and LSI. Both Eberhart and Russell and AMMI results are comparable in identifying stable genotypes for the test environments.Not Availabl