Concurrent improvements in maize yield and drought resistance through breeding advances in the U.S.Corn Belt.

Abstract

Drought increasingly challenges rainfed maize (Zea mays L.) production worldwide, with pressures expected to intensify under future climate scenarios. Recent studies have examined the genetic and physiological bases of yield and drought tolerance improvements in maize; however, comprehensive, field-based quantification of synchronous improvements of yield and drought resistance across diverse environmental conditions remain limited. By compiling a dataset of 92,096 hybrid-trial observations across the U.S. Corn Belt (2000-2020), our environmental index approach provides evidence of consistent yield increases across diverse environmental conditions. Using linear mixed-effects modeling, we reveal these gains are accompanied by enhanced drought resistance during the grain filling period. Projections suggest that by 2100, new hybrids could transform drought resistance, reducing yield losses by 17.8% compared to old hybrids, suggesting the potential of breeding innovations to buffer maize against drought stress. This study highlights recent breeding efforts, reinforcing adaptative capacity of maize and providing a promising pathway to sustain food security in a warming climate.