Corn genetics have come a long way. Patrick Schnable, a professor of agronomy and director of Iowa State University's Center for Plant Genomics addressed this topic and recently shared his ideas on how far genetics can go at the 2012 Iowa Master Farmer's fall meeting in Ames. He noted that future yield potentials of at least 350 bushels per acre are predicted to be more commonly attained by farmers on a commercial scale.
"If current trends continue, about half of that yield increase will likely be due to improvements in genetics," he says. "The other half is the role that you all have as farmers who grow the corn -- that is, improved agronomic practices." Schnable says genotyping (finding DNA differences among individual corn plants) is now much less expensive than even a few years ago. "That is not the hard part anymore," he explains. "Now, the hard part is phenotyping."
It's getting harder and harder to increase yields, which should concern everyone
Phenotyping involves characterizing traits among individual hybrids. However, this is expensive, and with rising costs of inputs and more variable weather patterns, Schnable says, new research is required to keep the yield curve rising. "It's getting harder and harder to increase yields," he adds. "This is something that should concern all of us."
Schnable and his colleagues released to the public DNA sequence data from the $30 million B73 maize genome sequencing project funded by the National Science Foundation a couple years ago. "This project was a major challenge," he says.
Schnable compares this research to the Lewis and Clark expedition which helped discover the American continent. "It was an exploration of the unknown. The explorers didn't know what they would find and neither did we," he explains. However, the rewards for the two projects are similar. "Both kinds of projects have payoffs that continue far beyond the period during which they are conducted."
Plants grow differently on different fields, in different times, in different environments
A big step is identifying single-nucleotide polymorphisms (SNPs) associated with multi-gene traits. So, the process requires genetic diversity, as well as accurate genotyping and phenotyping data – which Schnable says maize (corn) is perfect for. "It turns out that maize is extremely genetically diverse." However, collecting phenotyping data is difficult. "Plants grow differently on different fields, in different times, and in different environments," he adds, noting problems with contained research projects. "Plants do not grow in fields the way they grow in greenhouses."
USDA recently awarded ISU a $1.4 million grant to develop a high throughput phenotyping technology to be deployed in field plots -- a GPS controlled robot to collect and analyze images of crops, including the number of plants, leaves, etc. In the longer term, Schnable hopes to establish regional stations across the U.S. and in farmers' fields to study how crops perform under a variety of environmental conditions, as well as which traits matter under those conditions. He says this directly relates to drought tolerance – something several seed companies have addressed lately. "There is no one gene that is going to give drought tolerance," he says. "It's very complex."
There is no single gene that gives corn drought tolerance—it's more complex
Genetic makeup can allow crops to perform well under drought but poorly under normal conditions, poorly under drought but well under normal conditions, poorly under both, or well under both. Schnable says the goal is to eventually create hybrids that perform well under both droughty and normal conditions.
To accomplish this, he says continued support for ISU and the College of Agriculture and Life Sciences is required, along with plant science research at federal agencies – including the National Science Foundation's Plant Genome Research Program. This also means training the next generation of scientists to continue crop and yield improvements. "There is still a lot of room for improved agronomics," he says. "I think it's essential that we educate young minds in a wide range of scientific disciplines."