Genotype × Environment Interaction and Yield Stability of UiTM Advanced Rice Lines Across Two Malaysian Environments

Genotype × Environment (G×E) interaction is a key determinant of yield stability and adaptability in rice under varying agro-ecological conditions. This study evaluated five gamma-irradiation-derived UiTM advanced rice mutant lines alongside six commercial varieties across two Malaysian locations to assess yield performance, phenotypic variability, and preliminary adaptability. Although we detected significant genotype × environment interactions, the limited number of test sites constrains stability inference and highlights the need for broader multi‑location trials. Two-way ANOVA detected significant (p < 0.001) effects of genotype, environment, and the G×E interaction for most agronomic traits, with genotypic variation prominent in flowering and yield traits, while environmental factors mainly influenced plant height and spikelet number. Significant crossover interactions for yield-related traits indicated differential genotype performance across environments. Several UiTM mutant lines exhibited stable flowering and yield, suggesting broad or specific adaptability. Correlation analysis revealed strong positive relationships among yield components, and principal component analysis identified yield traits as the primary contributors to phenotypic variability. Cluster analysis categorized genotypes into early-maturing, high-yielding, and late-maturing types with larger spikelet numbers. Overall, the results highlight the importance of multi-location testing for varietal selection and demonstrate the potential of UiTM mutant lines as stable, climate-resilient candidates for sustainable rice production in Malaysia.