Crop management practices are more important for modern than past maize genotypes

Farmers continuously grow modern genetic products under ever-evolving management practices, they adopt new crop genotypes in the context of greater resources provided by intensified management systems. While previous studies have primarily focused on the individual contributions of maize breeding or management to yield increases, our study examines the interaction of innovation in both areas. Evaluate the interaction effect between historical changes in US maize crop management practices and long-term breeding on grain yield and carbon footprint. We tested genotypes widely sold in the US Midwest, from 1960 to the present, under management practices that reflect historical to modern changes in the region’s cropping system. Then, through life cycle assessments, we calculated the carbon emissions and carbon intensities (emissions of CO 2 equivalents per unit of land or product, respectively). As expected, modern genotypes outperformed older ones across all management practices. However, modern genotypes responded positively to intensive modern management treatments (2.4 Mg ha −1 ), while the oldest genotypes yielded the same under historic and modern management practices. This indicates that management plays a greater role in fulfilling the higher yield potential of modern genotypes compared to older ones, resulting in contrasting yield genetic gain estimates across historical management practices (66 to 97 kg ha −1 year −1 ). Results also show that increasing input levels with modern genotypes will not necessarily lead to an increase in the carbon intensity of the grain produced because modern genotypes are more efficient at converting resources into yield. When considering the carbon intensity for each genotype using their respective management (e.g., 1960s genotypes grown with 1960s management, and so on), there was a 19 % reduction (p < 0.01) in emissions from 1960 until today. Overall, our study highlights the interaction of management and genotype innovation, which has important implications for understanding how breeding and management affected historical yields, the role of agronomic changes in realizing the genetic yield potential of modern genotypes, and the environmental impact of agriculture. • We studied the interaction between historical management practices and genotypes. • Old genotypes yielded the same under past and modern management practices. • Modern genotypes responded positively to modern management practices (2.4 Mg ha −1 ). • Modern genotypes show greater yield variability than older ones due to this higher yield response. • Increasing inputs with modern genotypes did not lead to a larger carbon footprint per ton of grain.