A corn gene identified from a 118-year-old experiment at the University of Illinois could boost yields of today’s elite hybrids with no added inputs. The gene, identified in a recent Plant Biotechnology Journal study, controls a critical piece of senescence, or seasonal die-back, in corn.
Urbana/USA — Dating back to 1896, an experiment at the University of Illinois was designed to test whether corn grain composition could be changed through artificial selection. At that time this was a relatively new concept introduced by Charles Darwin just 37 years earlier. Repeated selection of high- and low-protein corn lines had the intended effect within about 10 generations. As selection for the traits continued, however, additional changes were noticeable.
One of the things that was noted as early as the 1930s was that the low-protein line stays greener longer than the high-protein line. Staying green longer into the season can mean more yield. The plant continues photosynthesizing and putting energy toward developing grain. But, until now, no one knew the specific gene responsible for the stay-green trait in corn.
Anne Sylvester, a program director at the National Science Foundation, describes the stay-green trait as a ‘fountain of youth’ for plants because it prolongs photosynthesis and improves yield. “This is a great basic discovery with practical impact," she added.
The discovery of the gene was made possible through a decade-long public-private partnership between Illinois and Corteva Agriscience. Moose and Illinois collaborators initially gave Corteva scientists access to a population derived from the long-term corn protein experiment with differences in the stay-green trait. Corteva scientists mapped the stay-green trait to a particular gene, NAC7, and developed corn plants with low expression for the trait. Like the low-protein parent, these plants stayed green longer. They tested these plants in greenhouses and fields across the country over two field seasons.
Not only did corn grow just fine without NAC7, yield increased by almost 5 bushels per acre compared to conventional hybrids. Notably, the field results came without added nitrogen fertilizer beyond what farmers typically use.
References: “Identification and characterization of a novel stay-green QTL that increases yield in maize,” published in Plant Biotechnology Journal [DOI: 10.1111/pbi.13139]. Authors include Jun Zhang, Kevin A. Fengler, John L. Van Hemert, Rajeev Gupta, Nick Mongar, Jindong Sun, William B. Allen, Yang Wang, Benjamin Weers, Hua Mo, Renee Lafitte, Zhenglin Hou, Angela Bryant, Farag Ibraheem, Jennifer Arp, Kankshita Swaminathan, Stephen P. Moose, Bailin Li, and Bo Shen.