Crop Breeding for Weather Extremes

Only one corn-breeding line out of about 150 remained standing after a derecho slammed into Beck's Superior Hybrids nursery, near Marshalltown, Iowa, last summer.

Winds exceeding 100 mph are an extreme test in standability for any experimental corn line, but the fact the variety stood like a tree when thousands of actual trees were blown over during the violent windstorm punched its ticket to further development. The corn line could help create future hybrids that may withstand high winds without lodging.

"We know that will be a strong line that will be bred heavily," says Tom Koch, breeding manager for Beck's.

With an ever-changing climate, breeding crops that are more weather resilient is a priority for seed companies. Koch says combining the attributes of racehorse varieties -- known to produce big yields when the weather cooperates -- and a workhorse variety that better withstands adverse weather is more important than ever.

"Weather extremes seem to be getting more intense," Koch explains. "Farmers are going to need a complete or broad defensive package to fit their needs."

Grain farmer Fred Yoder, Plain City, Ohio, couldn't agree more.

It's rare the perfect growing season occurs. How often does a farmer get plentiful and timely rains, but not too much? Or, enough heat units to promote quick germination and uniform emergence, but few, if any, scorchers during the reproductive period? Or, crops that avoid hail, damaging wind and other weather calamities?

"In 40-plus years of farming, I can think of one or two perfect seasons," Yoder says. "You need good risk-management tools, or you can lose the farm. It all starts with the seed."

The climate is changing rapidly, according to the Fourth National Climate Assessment. Weather extremes -- drought, heat, rain events, violent storms -- are becoming more frequent and intense as a result, says Bryce Anderson, DTN ag meteorologist emeritus. Increasingly challenging growing conditions threaten crop production and the nation's food and fiber supply.

Whether it's corn, soybean, cotton, sorghum, wheat or any other crop, Yoder believes one way to maintain and hopefully increase yields in the future is breeding crops to be more weather resilient. He's chairman of the North American Climate Smart Agriculture Alliance, a farmer-led platform for inspiring, educating and equipping agricultural partners to innovate effective local adaptations that sustain productivity and enhance climate resilience.

Farmers want and need seed that's a combination of a racehorse and workhorse, Yoder contends. He believes the industry is making strides to breed plants that are better at withstanding weather extremes associated with climate change.

An intense rainstorm this spring that covered emerging soybeans for several days solidified Yoder's beliefs.

"They should have died, but by golly they made it," he says. "What it really comes down to is minimizing risk as far as new varieties."

SEED INDUSTRY EFFORTS

Koch says Beck's has and will continue to develop a broad germplasm base to help crops mitigate the effects of adverse weather. The Atlanta, Indiana-based company sells corn, soybean, soft red winter wheat, sorghum and cover crop seed.

The company conducts research on all the crops it sells, but its internal breeding efforts focus solely on corn.

As part of its breeding research, Beck's researchers keep track of climatic data and document how different high-yielding corn inbreds and hybrids react to a variety of weather conditions. This helps breeders create lines that are more tolerant of heat, cold, drought, wind and wet conditions.

"The same genetics that may (perform) better in a drought are not necessarily the same genetics that work under high winds," Koch says.

Beck's uses a combination of crop scouting, weather stations, in-field sensors, yield data, drones, machine learning and predictive analytics in the breeding process.

This year is the epitome of extreme weather for Charlie Cook, a senior cotton breeder for Dyna-Gro Seed. The Texan says heat and drought are normally the weather worries for crops in the state. But this year, persistent, heavy rain didn't allow him to plant cotton at two research plots for the first time in his 30-year career.

The "crazy year," Cook says, reinforced the need to breed hardy plants. Despite adequate rain this year, drought is still his No. 1 concern.

"We've lost more cotton to drought in West Texas than will ever be lost to rain," he says.

Drought tolerance in corn has also been a longtime focus of company seed-breeding efforts. Corteva Agriscience has AQUAmax, Syngenta sells Agrisure Artesian and Bayer features DroughtGard, just to name a few.

Cook's approach to breeding cotton to be more weather resilient is not sacrificing seed size for yield. Some cotton is bred to have smaller seeds in bolls, which leaves room for more lint. However, Cook says small seeds don't grow as well in dry, cold or crusted soils. Small seeds have less water and nutrient storage capacity.

"My bigger-seeded varieties will come through (emerge and grow) just about anything. They have tremendous seedling vigor since they have a bigger radical and cotyledon (than small seeds)," Cook says.

Many Dyna-Gro larger-seeded cotton varieties have 180,000 seeds per bag compared to 220,000 seeds in a bag for smaller-seeded varieties, he continues.

Cook also thinks more shorter-season cotton varieties may be bred in the future to help counteract dry and hot conditions, and dwindling water supplies for irrigation.

UNIVERSITY RESEARCH

Researchers at the University of California-Riverside have identified two genes in recent years that may help crops endure warmer temperatures better. Plants, according to researchers, react to shifts of even a few degrees.

Global warming could reduce crop yields by one-third by 2050, according to a press release from the university. The discovery of the heat-sensing HEMERA and RCB genes by a team of scientists led by Meng Chen, a botany and plant sciences professor, may ensure a stable food supply.

Warm temperatures are a signal to plants that summer is coming. Anticipating less water, they flower early then lack the energy to produce more seeds, which lowers yield.

By modulating the expression or function of the HEMERA or RCB genes through gene editing or breeding in a specific crop, it could improve plant responses to warm temperatures. Then, targeted breeding can occur.

"To make crops more resilient, we have to uncover the inner workings of how plants sense and respond to temperature and other extreme environmental conditions," Chen says. "We are in the discovery stage. By discovering the new genes that are involved in temperature and sensing, there will be more (companies) working on this."

CLIMATE SHIFT?

Climatic data shows a warming trend is underway, especially in the northern latitudes. That is causing an unequal distribution of increased energy, which is likely at the heart of more frequent and extreme weather events, according to Bryce Anderson, DTN ag meteorologist emeritus.

Drought conditions tend to last a little longer, rainstorms exceeding 2 inches occur more regularly and violent windstorms with high winds may happen more often.

"Climate change doesn't necessarily cause individual (weather) events to happen. But, it enhances the potential of storms and events to reach upper-end levels of damage and intensity," Anderson says.

The following are conclusions from the Fourth National Climate Assessment from the U.S. Global Change Research Program, based in Washington, D.C.:

-- Global annual average temperature has increased by about 1.8°F from 1901 to 2016. Human activities and greenhouse gas emissions are the dominant cause.

-- The annual average temperature in the contiguous United States has increased by 1.2°F over the last few decades and by 1.8°F relative to the beginning of the last century.

-- Annual precipitation has increased by 4% since 1901 across the United States with strong regional differences: increases across the Northeast, Midwest and Great Plains, and decreases in the Southwest.

"Weather extremes will continue to be challenging to get dependable yields. That is the bottom line," Anderson says. "(Crop) breeding efforts can help mitigate yield loss or open the window of tolerance a little longer."

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For More Information:

-- Beck's Hybrids:
www.beckshybrids.com

-- Dyna-Gro Seed:
www.dynagroseed.com

-- North America Climate Smart Agriculture Alliance:
nacsaa.net

-- University of California-Riverside, "Discovery is key to creating heat-tolerant crops":
news.ucr.edu/articles/2021/04/06/discovery-key-creating-heat-tolerant-crops

-- Follow Matt on Twitter @progressivwilde

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