Genetic Control, Stability, and Multivariate Analysis of Wheat Seed Quality Traits in Elite Pure Lines Under Mediterranean Environments

Grain quality traits in wheat (Triticum aestivum L.), including protein content, gluten strength, and carbohydrate composition, are key determinants of end-use performance and breeding potential. This study assessed the genetic variability, stability, and multivariate relationships of seed quality traits among elite F7 pure lines derived from six long-term cultivated wheat cultivars. Field trials were conducted across six contrasting environments to evaluate genotype, environment, and genotype × environment (G × E) effects on crude protein, fat, ash, starch, crude fiber, Zeleny sedimentation, carbohydrates, non-starch carbohydrates, and moisture. Combined ANOVA revealed that genotypic effects accounted for the largest proportion of variation, though significant environmental and G × E effects were also observed. Broad-sense heritability was high for protein, Zeleny, and carbohydrate content. Stability analysis using the Stability Index (SI) highlighted A1, A2, A4, C2, E1, and F2 as genotypes combining high mean performance with a consistent expression across all environments. Principal component analysis (PCA) illustrated key trait relationships and trade-offs, particularly the negative association between protein-related traits and carbohydrate accumulation, while revealing the partial clustering of genotypes with similar quality profiles. AMMI and GGE biplots further supported broad adaptation for some genotypes (e.g., E1, F4, E2 for crude protein; F3, F4, E2 for Zeleny) and trait- or environment-specific performance for others. Correlation analyses confirmed positive associations between protein and gluten strength, and negative correlations with carbohydrate traits. Overall, targeted pure-line selection effectively exploits intracultivar genetic variation, offering a practical strategy for identifying superior, resilient wheat lines for breeding programs across diverse environments.