Maize yields could benefit from increased vapor pressure deficit in hot managed environments

Abstract Recent studies highlight the adverse effects of increasing vapor pressure deficit (VPD) due to climate change on maize yields. Maize breeders are utilizing available genetic diversity to address these challenges. However, contrasting ecophysiological properties and genotype by environment interactions (GEI) often hinder these efforts. This study by the Agricultural Institute Osijek, in collaboration with Turkish company Tarım Kredi Tohumculuk, explores the adaptation of maize germplasm to hot, managed environments in Türkiye, originally bred for Southeast and Central European rainfed conditions. Over an 11-year period (2009–2019), multi-environment trials (MET) were conducted in two stages. In cycle 0 (C0), 22 hybrids were evaluated across 17 environments in Croatia and Türkiye. In cycle 1 (C1), MET was conducted in 18 Turkish environments. Complete linkage hierarchical clustering based on hybrid performance and climatic variables revealed two distinct clusters with positive or negative responses to increasing VPD in C0. In C1, genetic variances increased with rising VPD, maintaining distinct responses. Our findings align with reports on the limited transpiration trait in maize and sorghum, suggesting that while such traits can reduce water loss, they may also limit yield potential in high-VPD environments.