Rob McClung watches clocks, but not the usual kind.
Now, the Dartmouth University professor has unveiled new research that could lead to higher crop yields, particularly in areas such as the Upper Midwest and southern Canada with short growing seasons.
Given the world's burgeoning population, "We really need to accelerate yield increases, and this has the potential to help," he says.
McClung is an expert in the circadian clock, which controls the circadian rhythm, the 24-hour cycle that affects how plants and humans respond to daylight and darkness.
Jet lag -- the result of moving across time zones -- is one example of how people are affected, he says.
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The new research, conducted by scientists in South Korea, Wisconsin, Wyoming and Dartmouth in Hanover, N.H., identified a gene called Gigantea as being responsible for natural variation in the circadian clock of Brassica rapa. A species of field mustard from which turnips, cabbages and other vegetables have been developed, Brassica rapa is grown in a wide south-north range, including the Mediterranean to northern Europe and southern China to northern China.
The newly announced research found different versions of the Gigantea gene affect many aspects of plant performance, including timing, seeding development and resistance to environmental stresses like extreme cold and high salt.
"We don't understand, mechanistically, entirely how it all hangs together. But what we've now got is a gene that, if you manipulate it, you can change clock function, change salt tolerance, change freezing tolerance. These are all traits that are of potential interest to plant breeders," McClung says.
Interest might be particularly strong in the Upper Midwest because of its short growing season, he says.
Farmers, soil scientists and others in the Upper Midwest say soil salinity is becoming a bigger problem, potentially making the new circadian clock research even more useful in the region.
Just one gene, but ...
Marcelo Carena, North Dakota State University corn breeder, hasn't seen the Dartmouth-led research, but was given a brief description of it by Agweek.
He says the research might be of some benefit to his work. He doesn't expect any immediate gain, however.
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"The discovery of a gene, one gene, helps build knowledge," Carena says. But "identifying one gene is very far from the objective of developing salt- and cold-tolerant varieties for these two genetically complex traits. Besides, they are difficult to measure and highly influenced by the environment."
McClung hopes additional, still-to-be-conducted research could provide more insight into what the newly announced research found.
"We've done this with one gene," he says. "But we've mapped at very crude levels several other genes that (also) affect the circadian clock. We would really like to repeat this with another gene to nail down the demonstration that, by manipulating the clock, you can affect plant performance and yield."
He's uncertain when such additional research might be available. But it's possible that "in three to five years, we can have some pretty solid data."
Three decades of work
McClung has been studying circadian clocks for 30 years. He describes himself as "John the Evangelist, spreading the message of circadian clocks."
Recent advances in genetic coding have accelerated researchers' ability to demonstrate the importance of circadian clocks in plants, he says.
One of his goals is to convince agriculturalists that "the clock can be a useful tool in (crop) breeding programs," he says.
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A growing global population will require world crop production to double by 2050, but yields for corn, rice, wheat and soybeans, the world's four major crops, aren't increasing fast enough to meet that need, McClung says.
Making greater use of the circadian clock can speed the crop breeding process and boost the rate at which yields increase, he says.
