A new crop stress-management concept may help corn and other field crops better cope with moderate drought and heat stress and limit stress-related yield loss.

“When plants respond to stress, it's at the expense of yield potential,” says Fred Below, a University of Illinois plant physiology professor who specializes in corn production. “If plants can overcome that stress, the yields are better.”

Below studies ethylene, the natural, gaseous plant-growth regulator that plants release and use to “communicate” with each other. When plants are under stress, they release more ethylene. Neighboring plants sense the change and respond to it. When plants do not sense ethylene, Below has found the effects of stress on yield may be reduced.

“We've found that a sprayable, synthetic ethylene blocker, 1-methylcyclopropene (1-MCP), doesn't deter corn plants from releasing ethylene, but it does alter how plants sense the ethylene,” he says, noting that 1-MCP has been commercially used for years to slow fruit ripening and preserve fresh flowers. “Essentially, 1-MCP makes the corn plants insensitive to ethylene's release and limits the excess ethylene's impact on yields.”

HOW MUCH IMPACT product use has on preserving corn yield potential is hard to discern. Below likens 1-MCP to the product airplane passengers take to prevent catching an airborne illness. If you take the pill and do not get sick, you don't know if it's because the product worked or because you weren't exposed to any illness on the plane.

“In other words, it will be hard for farmers to predict the amount of yield response to stress relief, because they won't know how much stress is decreasing yield,” says Below. “We do know that 1-MCP gives plants the chance to achieve high yield potential, because we have seen some large yield increases in replicated field trials. However, we have also seen a few yield decreases, so there is still work to do.”

WHILE THE BEST use of 1-MCP may be during periods of moderate weather stress like persistent high temperatures or drought, high plant populations may be another instance where the product may have a positive influence. Below says 1-MCP works in several different crops, but he believes corn is the best fit because it's a determinate crop.

Corn is determinate because it produces one stalk, one tassel, one ear, so the plant has one shot of “getting yield right.” Conditions during each of those growth stages can affect that specific growth stage. In contrast, a soybean plant is indeterminate because it produces several flowers and pods, so even when some may be aborted due to stress, others remain. Therefore stress is likely to have less impact on the soybean yield.

“Determinate crops make key decisions as they grow that are irrevocable for yield,” Below says. “Excess ethylene can have a lifelong impact. You cannot reverse its effects.”

The 1-MCP product will be marketed under the trade name Invinsa Crop Stress Protection, from AgroFresh Inc., a subsidiary of Rohm and Haas and Syngenta AG. Researchers are still exploring application timing and compatibility for best results.

“It appears application during the early vegetative development stage may be best. This would provide the crop with some stress protection through flowering,” Below says. “We hope we can also make one pass and apply 1-MCP at the same time as post herbicides.”