Phenotypic characterization and resilience assessment of wheat genotypes under single and combined abiotic stresses

Climate change and limited resources are intensifying abiotic stresses in wheat production, creating an urgent need for varieties that combine high yield with reliable performance under variable conditions. However, selecting for yield under optimal or single-stress conditions often fails to predict how genotypes will perform under complex, real-world challenges.

We evaluated 56 wheat genotypes under four environments: fully fertilized and irrigated (FFI), water deficit (WD), nitrogen deficit (ND), and combined water-nitrogen deficit (CWND). To quantify resilience, we developed a composite D-value index by integrating stress-response ratios of seven agronomic traits using PCA, fuzzy membership normalization, and entropy-weighted aggregation.

Both WD and ND reduced grain yield by 21-22% relative to FFI, while CWND caused a further decline (-31%), representing the greatest reduction among all treatments. Stress environments fundamentally altered the relationships between key agronomic traits. Genotype performance varied considerably across environments: XM296 maintained relatively high yield under single stresses but showed limited multi-trait stability under combined stress; LX99 showed stable performance across diverse stresses while retaining high yield potential; in contrast, XN20 exhibited relatively high tolerance at the expense of low productivity.

Given the environment-dependent nature of resilience, breeding strategies should balance broad adaptation with improvements targeted at the dominant stress patterns in key production regions. This approach will better translate genetic gains into stable yields in farmers' fields.