This innovative approach could help maximize radiation use efficiency (RUE), a key determinant of crop yield, offering promising pathways to meet rising global food demands amid climate challenges.
Radiation use efficiency (RUE) measures how efficiently crops convert sunlight into biomass. Current RUE values for maize, the world’s most important grain crop, are estimated to be less than one-third of their theoretical maximum. This shortfall highlights significant untapped potential for improving crop yields, especially given the need to secure food supplies for a growing global population. The distribution of light and leaf nitrogen within the canopy plays a major role in determining RUE, but previous studies often made unrealistic assumptions about leaf area distribution. This new research, focused on maize—a C4 crop—explores how optimizing both the light and nitrogen distributions can unlock greater efficiency.
A study (DOI: 10.34133/plantphenomics.0217) published in Plant Phenomics on 29 July 2024, has significant implications for breeding and crop management practices.
To test the hypothesis that RUE could be maximized by aligning leaf area and nitrogen within the canopy, researchers simulated a variety of virtual maize canopies. The simulation adjusted key parameters such as leaf inclination angle, vertical leaf area (LAI), and nitrogen distribution. A multilayer canopy photosynthesis model was then used to evaluate the performance of these canopies in terms of dry matter accumulation (ADM) and RUE. Results revealed that ADM and RUE initially increased, peaked, and then declined as the LIA increased. The maximum ADM values were recorded at different LAIs ranging from 1,978.51 to 2,056.40 g·m−2 for LIAs between 63.48° and 71.08°. Similarly, the RUE values peaked at around 3.82 to 3.22 g·MJ−1 for different LAIs. When assessing ADM and RUE with varying leaf nitrogen and area distributions, the simulations showed that ADM and RUE reached their highest values when leaf nitrogen allocation matched the vertical distribution of leaf area, emphasizing the importance of aligning nitrogen distribution with the canopy structure. Moreover, the optimal ideotype canopy—with an LAI of 5, LIA of 71.08°, and nitrogen peak at the seventh canopy layer—achieved the highest RUE of 4.157 g·MJ−1. The study highlighted that matching the vertical distribution of light and nitrogen could optimize canopy RUE, particularly when more leaf area was positioned lower in the canopy, demonstrating the potential of optimizing canopy structure for higher crop productivity.
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