Tom Hall, Senior Agronomist, Rooster Strategic Solutions
Photosynthesis, as any first-year agronomy student (or any farmer) can tell you, is the engine that drives plant growth, fueled by sunlight, carbon dioxide, and water. It’s the very foundation for plant production and the generation of oxygen that sustains life on earth. Which is why many are surprised to learn that the process is horribly inefficient, with plants using less than 1 percent of the sunlight available through the course of a growing season.
Cloudy days are an obvious obstacle. Wind can move leaves in and out of sunlight throughout the day. And as the plant produces a canopy, lower leaves are literally shaded out of the photosynthesis equation altogether.
What’s more, while plants need sunlight to grow, too much direct light can be damaging. To counter this, plants use an evolutionary process called nonphotochemical quenching (NPQ), which allows them to emit energy from excess light in the form of heat. But this “breaker switch” doesn’t trip on or off nearly fast enough. It can take several minutes before a leaf in full sunlight will begin discharging energy as heat, and even longer for a shaded plant to turn the process off.
This was the challenge taken up by Dr. Stephen Long and his colleagues at the University of Illinois at Urbana-Champaign. By tweaking the genetic process, Long hoped to speed up the NPQ process, allowing plants to better use the sunlight available throughout the day. And, according to the study recently published in Science magazine, it looks as if they’re on the right track.
Increasing soybean production by 20 percent. Long and his associates focused on the genes responsible for NPQ, designing eight different strains of soybeans and planting them in the Morrow Plots, the oldest experimental crop field in America. The leaves of these genetically modified plants performed as the researchers hoped, enabling them to use a higher percentage of available light. At harvest, five of the eight strains showed significantly higher yields. The top strain increased yields by 33 percent. Three of the strains showed no improvement. Altogether, the test averaged yield increases across all eight strains at 20 percent. Put another way, a future Illinois farmer could see a 12-bushel-per-acre yield bump using these modified seeds.
Granted, this was one field test on a fairly small scale. Long and his colleagues are expanding the program this year to focus on larger trials. This is exciting news for farmers and for the general public for several reasons, beyond a potential yield bump. First, Dr. Long’s work increases yield by increasing the plant’s efficiency, which means less pressure on resources like P and K fertilizers. And because the work is based on genetic modification to increase the sustainability of crop production – beyond making the plants immune to herbicides – it may help spur the public’s acceptance of this vital tool.
What’s more, the lessons learned may someday increase yields in crops other than soybeans. Long and his team, backed by Gates Ag One, a company owned by the Bill and Melinda Gates Foundation that helps fund Dr. Long’s testing, hope to expand genetic testing to other crops, including rice and wheat. That fact that this work is being done in the public sector is a huge win for university researchers, who, in recent years, have taken a back seat to private sector research. A United States agriculture that has both a thriving public and private research arm is the best hope for supplying the world’s rapidly increasing demand for food and fiber.