Multi-trait evaluation of maize hybrids for yield stability under maize–soybean strip intercropping in Southwest China

Maize–soybean strip intercropping is promoted in Southwest China to improve land use and diversify crop production, but maize hybrids vary in their ability to maintain yield under this system. Selection based on mean grain yield alone may overlook year-to-year variation, lodging risk, disease response, and ear-related traits. A two-year field experiment was conducted in Southwest China to evaluate ten maize hybrids under a locally used maize–soybean strip intercropping system. Yield, lodging and disease responses, plant architecture, ear traits, land equivalent ratio (LER), and economic return were evaluated using field-replicate data and multivariate trait analyses. Lechuang 7979, Tongyu 609, and Rongyufengzan combined relatively high grain yield with low year-to-year variation, whereas some hybrids with high yield in one year were more sensitive to annual conditions. Under the low absolute lodging rates observed in this experiment, these hybrids generally showed manageable lodging risk, moderate ear placement, and descriptively favorable ear-related profiles. The intercropping system had a total LER of 1.50 and a benefit–cost ratio of 3.98 under the tested conditions. These results identify the three candidate hybrids for further regional testing under maize–soybean strip intercropping.