Gonzalo Rizzo, Juan Pablo Monzon, Fatima A. Tenorio, Réka Howard, Kenneth G. Cassman, and Patricio Grassini

PNAS January 25, 2022 119 (4) e2113629119

Significance

After accounting for the effect of climate and improvements in agronomic management, we found the contribution of genetic technologies to increasing maize yield potential in favorable environments was substantially smaller than reported in previous studies. If genetic progress in yield potential is slowing in other environments and for other crops as well, future production gains will increasingly rely on yield gains from improved agronomic practices and/or increasing crop intensity where possible.

Abstract

Quantitative understanding of factors driving yield increases of major food crops is essential for effective prioritization of research and development. Yet previous estimates had limitations in distinguishing among contributing factors such as changing climate and new agronomic and genetic technologies. Here, we distinguished the separate contribution of these factors to yield advance using an extensive database collected from the largest irrigated maize-production domain in the world located in Nebraska (United States) during the 2005-to-2018 period. We found that 48% of the yield gain was associated with a decadal climate trend, 39% with agronomic improvements, and, by difference, only 13% with improvement in genetic yield potential. The fact that these findings were so different from most previous studies, which gave much-greater weight to genetic yield potential improvement, gives urgency to the need to reevaluate contributions to yield advances for all major food crops to help guide future investments in research and development to achieve sustainable global food security. If genetic progress in yield potential is also slowing in other environments and crops, future crop-yield gains will increasingly rely on improved agronomic practices.

See: https://www.pnas.org/content/119/4/e2113629119

Fig. 1. Simulated climate-driven yield potential (Yc) and average farm yield (Ya) for irrigated maize in three regions in Nebraska: Lower Niobrara (Top), Tri-Basin (Middle), and Upper Big Blue (Bottom). The green shadow indicates the range of simulated Yc across nine combinations of sowing date and hybrid maturity for each year. Box plots show Ya, with boxes delimiting the 25th and 75th percentiles and lines indicating fifth and 95th percentiles; the horizontal line within each box represents the median. Also shown are fitted linear-regression models for Yc (green) and Ya (red) and their associated slopes (± SEs). Slopes of fitted regression models were statistically different from zero in all cases (P < 0.01).