Radiation Use Efficiency: Moving to the Next Plateau.

The concept of radiation use efficiency (RUE) has been used to link solar radiation capture by crops with biomass and yield with more efficient systems producing the most biomass or yield per unit of photosynthetically active radiation captured. The original RUE concept was based on optimal growth conditions with no limitations in water or nutrients; however, evaluation of all observations of light capture by crop canopies can reveal the limitations to crop productivity. A limitation to field measurements of RUE has been an observation of light interception by the crop canopy throughout the growing season and that barrier has been eliminated through the application of remote sensing techniques which can be used to estimate the spatial variation in light interception across a field. Applying this technology to large scale observations of crop fields provides an indication of management practices which enhance light capture. Productivity increases are required to continue to produce the food and feed required to meet global food needs and refinement of existing concepts like RUE and water use efficiency will begin to unlock the potential we have in the genetic resources. Solar radiation is one of our critical resources and improving the efficiency of its use in crop productivity will benefit all humankind.