Inter‐annual and regional variability of agronomic and grain quality traits of major Korean wheat cultivars under multi‐environmental conditions

BACKGROUND Wheat agronomic performance and grain quality vary substantially depending on environmental conditions. However, few studies have evaluated agronomic performance, grain quality stability, and growth stage‐specific climatic regulation together across representative Korean wheat‐production environments. RESULTS Phenological traits and amylose content showed relatively high stability across multiple environmental conditions, whereas yield components and protein‐related quality traits exhibited pronounced environmental variability. Climatic gradients integrating radiation, temperature, and moisture structured environmental differences and were differentially associated with crop responses across growth stages. Early season climate primarily influenced phenological development, whereas climatic conditions during reproductive growth exerted the strongest control over yield formation and protein‐related traits. An integrated grain quality index further showed that environmental effects were reflected through changes in overall quality performance and differences in interannual stability. CONCLUSION Variations in wheat performance and grain quality across different environments were governed by structured climatic gradients and developmental timing rather than by isolated site effects. This study provides an analytical framework for distinguishing stable and environment‐sensitive wheat traits by integrating multi‐environment field trials, growth stage‐specific climate gradients, and composite grain quality assessment under Korean agro‐climatic conditions.