Improving Photosynthetic Efficiency for Improved Crop Yield

By Donald Ort

Feeding the world’s current population already requires 15% of the total net primary productivity of the globe’s land area and that will need to increase to 25% in order to meet the projected increase in agricultural demand this century. This near doubling of food production will have to be accomplished on globally declining acreage and during a time in which there will be ever increasing demand on cultivated lands for the production of bioenergy crops, while in the face of a changing global environment that has already resulted in decreasing global yield of some of the world’s most important food crops. The yield potential of crops is determined by their efficiency of capturing available light energy (i), the efficiency of converting intercepted light into biomass (c), and the proportion of biomass partitioned into grain (η). The remarkable yield gains of the Green Revolution in the middle of the 20th century resulted from plant breeders bringing η and i for major crops close to their theoretical maxima, leaving improved photosynthetic efficiency as the only yield potential determinant with sufficient capacity to double crop productivity. Opportunities to improve photosynthetic efficiency exist in readapting photosynthesis to the rapid changes in atmospheric composition and temperature, in redesigning photosynthesis for agricultural production and in applying synthetic biology to bypass evolutionary limitations and inefficiencies in photosynthesis. Recent work using a synthetic biology approach to lower the energetic cost of photorespiration will be presented.
 

Source: berkerly.edu