Genotype × Environment Interaction and Yield Stability of UiTM Advanced Rice Lines

Genotype × environment (G×E) interaction plays a pivotal role in determining the stability and adaptability of rice cultivars under diverse agro-ecological conditions. This study evaluated five gamma-irradiation-derived UiTM advanced rice mutant lines and six commercial varieties across 12 locations in Malaysia to assess yield performance, phenotypic variability, and stability. The two-way ANOVA revealed highly significant (p < 0.001) effects of genotype, environment, and their interaction on most agronomic traits. Notably, substantial genotypic variation was observed in days to 50% flowering (DTF50), days to maturity (DTM85), number of filled spikelets (NFS), and yield per plant (YLDPLT), while environmental effects were dominant for plant height (PH) and number of spikelets (NOS), highlighting the influence of location-specific factors such as rainfall and soil fertility.

Significant G×E interactions for traits including NFS, YLDPLT, and seed length-to-width ratio (SLSWR) indicated crossover performance among genotypes across environments. Several UiTM mutant lines demonstrated consistent flowering times and stable yield expression, suggesting their suitability for broad or specific adaptation. Descriptive statistics revealed high coefficients of variation in sterile spikelets (CV = 54.91%) and yield traits, indicating environmental sensitivity. The correlation analysis showed strong positive associations between yield components such as NFS, TSW, and YLDPLT, supporting their role as key selection criteria.

The principal component analysis (PCA) identified yield traits as major contributors to phenotypic variability (PC1 = 45.8%), while grain morphology traits loaded strongly onto PC2 (22.8%). The cluster analysis grouped the genotypes into two categories: early-maturing, high-yielding lines and late-maturing types with greater spikelet numbers. These findings emphasize the need for multi-location trials and a G×E analysis to guide varietal selection. The stable performance of the UiTM lines under varying conditions underscores their potential as candidates for climate-resilient rice cultivation in Malaysia.