Genotype × environment interaction and stability of grain micronutrients in wheat under organic and conventional...

Improving the micronutrient content of wheat grains remains an important objective for addressing micronutrient deficiencies in human diets. This study evaluated the performance and stability of seven wheat (Triticum aestivum L.) genotypes for grain iron (Fe), zinc (Zn), manganese (Mn), copper (Cu), and selenium (Se) concentrations across six environments, defined by three growing seasons under organic and conventional fertilization systems. Genotype, environment, and genotype × environment (G×E) effects were examined using Additive Main Effects and Multiplicative Interaction (AMMI) analysis and Genotype plus Genotype-by-Environment (GGE) biplot methods. Combined ANOVA demonstrated highly significant (P ≤ 0.01) influences of both G and E on all micronutrients, whereas GEI effects were dependent on the nutrient and significant for Mn, Zn, and Se. The initial two AMMI interaction principal component axes (IPCA1 and IPCA2) accounted for 99.63%, 90.59%, 78.57%, 93.05%, and 90.16% of the GEI sum of squares for Fe, Mn, Zn, Cu, and Se, respectively. Genotype stability was measured using the AMMI Stability Value (ASV), a composite measure based on IPCA scores, along with the Genotype Selection Index (GSI), which combines average performance and stability rankings. Patterns of adaptation specific to systems were identified across different fertilization regimes. The Local genotype concentrations of Fe (91.27 ppm), Mn (44.47 ppm), and Zn (50.29 ppm) rank as one of the top genotypes in both organic and conventional systems. IC8 consistently demonstrated the highest Se concentration (1316.6 ppb) and retained stable positions across both organic and conventional systems, suggesting wide adaptability. Conversely, P5 and IC17 demonstrated enhanced Cu and Zn performance mainly under conventional conditions, while Sids12 exhibited decreased stability in organic conditions. GGE biplot analysis further categorized test environments into system-defined mega-environments, demonstrating differing genotype adaptation between organic and conventional fertilization methods. In general, Local and IC8 demonstrated significant micronutrient accumulation alongside low sensitivity to GEI (low ASV and GSI), suggesting their potential as parental lines for developing wheat cultivars with broad or specific adaptation in biofortification initiatives aimed at low-input (organic) and high-input (inorganic) production systems.