Hot nights are confusing Kansas crops. What does that mean for the nation’s food supply?
As climate change causes warmer night temperatures in Kansas, agriculture could pay the price, according to a recent study.
Researchers at Kansas State University and North Carolina State University have evidence that when nights get warmer, it messes up the circadian clock genes in rice. Similar patterns of behavior are expected in Kansas crops, such as wheat, barley and corn.
“When it is really hot in the night, you really don’t know because you’re sleeping. But the plants do not have an option,” said Krishna Jagadish, crop professor at K-State and Adjunct Scientist at the International Rice Research Institute. “They still undergo distress and that’s why you start to see this impact.”
In Wichita, overnight temperatures have risen 2.7 degrees Fahrenheit since the 1970s. In Topeka, they’ve risen 3.4 degrees.
“When the night starts to get warmer, then the plants tend to respire more, metabolic activity starts to increase and then they lose the carbon that they would have got from photosynthesis,” Jagadish said. “With warming night and temperature, you tend to lose the carbon and therefore you lose yield and your quality starts to become poorer.”
K-State studies indicated a 5% reduction in wheat yield for each degree Celsius increase in temperature. In addition, a study for the United Nations found that rising global temperatures due to climate change is jeopardizing food security.
“If the nighttime temperatures throw the plants clocks off, and then everything gets off-kilter, then Kansas could have a lot of effect, especially being so important for food for the rest of the country,” said Colleen Doherty, associate professor of molecular and structural biochemistry at North Carolina State University. “The scary thing about climate change is its potential effects on crops and water. We could survive without some of the luxuries we’re used to, but food and water are pretty critical.”
Wheat and other starch grains will be impacted the most by rising overnight temperatures, causing a chain of events that could impact the entire nation.
“In wheat, the size of the grain becomes smaller,” Jagadish said. “You get more protein and lipids being deposited in the grain, so that actually alters your bran composition, having an impact on your flour-making properties, and also the taste of your bread.”
Another important crop for Kansas, corn, could also be susceptible to rising nighttime temperatures.
“Our hypothesis is that corn might be more affected in terms of both yield and quality, which would probably impact of biofuel industry,” Jagadish said.
Doherty and Jagadish started studying the impacts of rising nighttime temperatures seven years ago, choosing to study rice because it’s cheaper to use and has a similar scientific plant architecture to wheat and corn. They observed that when plants experience warmer nighttime temperatures, some genes expressed earlier and others express later than normal, disrupting photosynthesis and respiration.
“Plants have a clock like humans,” Doherty said. “They have a timing for everything and we know how we are if you’re jet-lagged, you’re a little bit screwed up and that’s what’s happening with the plants.”
When conducting the study, Jagadish used heaters in field conditions so that experimental plots were 2 degrees Celsius warmer than the control plots.
But not all is lost, according to Doherty. The next step is looking at different rice varieties and wheat varieties and how they behave under warmer nighttime conditions.
They will narrow down those varieties that do best and breed them to accommodate warmer overnight temperatures better, but it’s a difficult process.
“We’re trying to work with the breeders here to see if we can utilize these genotypes and make our wheat tolerant to these warming nights, but it’s going to take time,” Jagadish said. “It’s not going to be immediately available as agricultural installations are not easy.”
This process is going to take time, which is why researchers are starting now.
“It’s not like the entire wheat growing region across the U.S. and the world is going to be experiencing these temperatures almost immediately, right? That’s not true,” Jagadish said.
“When you do these studies, you’re trying to anticipate what’s going to happen, maybe two or three decades from now. How can we pace our scientific progress in achieving what we want to achieve, in terms of resilience to these sort of stresses, so we are ready if this happens?”
This story was originally published July 23, 2021 at 4:30 AM.
