Super Sorghum

By Kathy Meyer
Contributor

Grain sorghum producers often lament its inferiority complex to comparable row crops. But, that's about to change.

In 2016, industry leaders enthusiastically set in motion an initiative to explore and develop new frontiers for grain sorghum. Dubbed "super sorghum," an ambitious plan for advancing sorghum yields and markets is under way at the newly established Center for Sorghum Improvement at Kansas State University (KSU).

It's charged with expanding markets for sorghum and increasing the average U.S. yield from 62 bushels to 100 bushels per acre by 2025, says Sarah Sexton-Bowser, managing director for the Center. "The program is about bringing synergy to domestic research efforts to capitalize on the solutions grain sorghum offers to meet challenges in agriculture."

Initial support for the program totals $4.8 million -- $2 million each from the Kansas Grain Sorghum (KGS) Commission and the United Sorghum Checkoff, and $800,000 from KSU. Overseen by an advisory committee, Bowser will seek additional funding for projects that meet the "super sorghum" objectives and extend the program life beyond 2025.

In addition, the Kansas Department of Agriculture has committed another $200,000 to the initial funding. Bowser's aim is to use the total 10 years of funding and build it into a foundation that will extend into a second decade of operation.

"When farmers look at which crops to use in their rotations, they feel technology is lacking for grain sorghum. The question becomes: How do we leapfrog sorghum technology in relation to comparable row crops in farmer cropping systems?" Bowser asks.

"Whether it's breeding genetics, advancing input technology or developing more markets, grain sorghum producers want to make the most of this environmentally hardy crop," she says. "Grain sorghum is a 'workhorse' when it comes to grain crops, and producers want to find ways to reap more value."

Sorghum's Potential. The renewed efforts toward grain sorghum coincide with producers' interest in the potential to gain back production acres that have limited irrigation opportunities, preserve the dwindling Ogallala Aquifer and take advantage of growing consumer demand for whole grains.

Central-Kansas farmer Clayton Short sits on the board for both the KGS Commission and the United Sorghum Checkoff. Short farms 2,000 acres in Saline County using a sorghum, soybean and wheat rotation, with 250 acres of his cropland irrigated. He's a firm supporter of the efforts under way at the Center for Sorghum Improvement.

"We need research to improve sorghum yields and, ultimately, reduce the price discount relative to corn, which has traditionally been a 4.6% discount," Short explains. "Expanding opportunities for livestock feed, ethanol, human and pet food can open new doors for consumptive demand."

Short believes it makes good economic sense to put more focus on sorghum production. "Sorghum performs well on marginal soils and with limited rainfall. Growing corn and soybeans requires more inputs and irrigation."

Research Focus. Short sees the need to develop sorghum varieties with improved genetics in three key areas:

• Cold Tolerance. Develop hybrids that allow earlier planting and earlier maturity in cool weather. Grain sorghum doesn't develop in the same temperature ranges compared to corn.

• Standability. Often a sorghum crop may use all its nutrients to develop the grain head, which can sacrifice stalk strength. Negative conditions such as heat or drought will stress the plant, as will the 30 to 40 mph winds common in the Plains states. Better standability characteristics are needed so stalk stress doesn't leave sorghum laying on the ground.

• Higher Yields With The Same Inputs. Create sorghum hybrids with better genetics for water and nutrient efficiency while achieving yields similar to corn.

Gary Pierzynski, agronomy department head at KSU, says, "The overarching goals driving the funding effort is research to increase sorghum yields and address the entire sorghum value chain. For yield, researchers break that down to look at genetic yield potential and yield-limiting factors."

Pierzynski outlines two primary areas that offer the greatest potential for yield advances:

• Genetics. "We look at the architecture of the sorghum seed head -- what's the size of the head, the number of seeds per head and the size of the seeds?" he asks. "All of these considerations and others are wrapped together when sorghum breeders do selection in test plots to enhance yield. We watch those factors to select the genetics that will push the yield curve forward."

• Yield-Limiting Factors. "With this focus, we're not investigating the steady march of ever-increasing yields from the crop genetics. Instead, we look at environmental conditions that can hold back yields and what we can do to minimize the effects of those factors," Pierzynski says.

Environmental Stresses. Heat and drought tolerance rank among the harsh stresses that can limit sorghum yields. Research is looking at what can be done to limit their effect. "Sometimes the two stresses go together," Pierzynski says, "but that's not always the case.

"Obviously, heat can be accompanied by moisture shortage. However, heat stress alone-even when moisture is adequate -- can adversely affect pollination efficiency, achieving seed set and growth rate. You can have perfect environmental sorghum growth conditions, yet a week of extreme heat will cause a yield drag. We need to breed sorghum plants that can better survive those heat stresses."

Drought poses another yield-limiting factor despite sorghum's natural drought tolerance. "Sorghum is well-adapted to dry conditions compared to crops like corn, but we are looking at breeding and genetic strategies to develop sorghum hybrids that are even more resistant to drought conditions," Pierzynski says. "We look at the approach a plant takes to cope during drought stress. We're asking, what are the genetics that limit tolerance?"

Pierzynski points out cold stress can play just as big a role in limiting yield. Cold tolerance is another line of research. "If we can develop genetics that allow for earlier spring planting and successful germination, maybe we can avoid some of the stresses of heat and drought in the summer. Also, in the Great Plains, we need to consider the yield-limiting stress of a cool 60ºF night in the summer during critical growth stages."

Weeds and insects are two other areas researchers

need to explore to improve sorghum yields. "Currently, there are no commercially available over-the-top, postemergence grass herbicide options for sorghum, although one is on the way. We're working on weed-control strategies that may or may not involve crop genetics," Pierzynski says.

Rapidly growing sugarcane aphid populations in sorghum-growing regions represent another threat to sorghum yields. Researchers plan to screen various hybrids for genetic resistance. Initially, they see several hybrids that exhibit some resistance to the insects and others that may be completely immune.

(AG/SK)

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