Eastern gamagrass, a cousin to corn that thrives without annual replantings, was a common sight to the early settlers. It may become a common sight again—first as a forage crop and later as a dual-purpose forage-grain crop of the 21st century.

Seed head of a high-producing mutant of eastern gamagrass

This warm-season grass could relieve farmers’ anxiety in future years like 1993, when many Midwestern fields remained wet through planting season.

Besides withstanding soggy soils, the deep-rooted grass is also drought resistant. Its growth—up to 8 feet high, and in bunches—also provides an excellent cover for wildlife while reducing soil erosion.

Now rising in popularity as a high-protein forage, eastern gamagrass also produces small grain kernels—about a seventeenth the size of corn—that may someday be fed to farm animals or ground into flour for bakery goods savored by nutrition-conscious consumers.

Grain from eastern gamagrass, with its slightly nutty flavor, has about a 30-percent protein content that is rich in the essential amino acid methionine.

Since pioneer days, the native American grass has fallen victim to the plow and overgrazing. Its comeback awaited scientists’ tackling some major bugaboos, such as poor seed yield.

"We still have a long way to go before we have a dual-purpose grain and forage crop, but it can be done," says Chester L. Dewald, an ARS agronomist in Woodward, Oklahoma.

Even as crosses between eastern gamagrass and corn can lead to modern corn hybrids with many new genes for plant disease resistance, such crosses could also benefit the grass, according to Dewald.

"Although genes from corn can’t be expected to make gamagrass seed yields match those of corn—at least not anytime soon—gamagrass is cheaper to grow because annual replantings aren’t needed."

"And," points out Gary Fine, former Plant Materials Center manager for USDA’s Soil Conservation Service in Manhattan, Kansas, "lowlands along creeks and rivers are often too wet to support annual crops such as corn but are ideal sites for gamagrass."

In 1974, SCS released to plant breeders the first experimental strain of eastern gamagrass germplasm, PMK-24, developed from an assemblage of seed collections from 70 locations in Kansas and Oklahoma. The same composite germplasm was released as a variety named "Pete" in 1988. By then the word was out that ruminant animals find eastern gamagrass highly palatable—the "ice cream" of forage crops. Cattle tend to overgraze it in preference to other grass species.

Rotational grazing among pastures with pure stands helps ensure vigor and make the most of the forage produced. It prevents livestock from overgrazing lush new growth while leaving tall clumps of old growth.

Dan Shepherd of Shepherd Farms, Inc., Clifton Hill, Missouri, rotates about 325 adult buffalo through 3 pastures totaling 135 acres on Chariton River bottomland. Starting when growth reaches a height of 2 feet or more in mid-May, he lets the animals graze it down to a height of about 10 inches.

From a nutritional perspective, there’s good reason to let livestock feast on the forage—its protein content is similar to alfalfa’s. As a hay, it may have a protein content up to 17 percent if harvested at about 6-week intervals, or just before seed heads appear. Dewald says, "Alfalfa may be the queen of legume forages, but eastern gamagrass is the queen of grass forages."

According to him, another reason farmers find gamagrass attractive is that it grows well on a wide variety of soils. It may thrive for several decades on wet or poorly drained soils where alfalfa stands would not persist more than 3 or 4 years.

At a 1993 field day held at Shepherd Farms, a University of Missouri forage specialist pointed out that high levels of phosphorus are not needed for eastern gamagrass to grow well, whereas each ton of hay harvested has generally taken up about 30 pounds of it.

And researchers may someday find a way to continually renew the soil with nitrogen for eastern gamagrass with interplanted legumes.

The popularity of eastern gamagrass is rising. In response to progress researchers have made in increasing seed yields and identifying management options, several growers in Nebraska, Kansas, and Missouri are now producing enough of the seed to adequately meet farmers’ requirements.

Much research remains to be done, however, on the problem of seed shattering before and during harvest.

Today’s harvestable seed yields are typically about 100 pounds per acre, although yields of 250 pounds are possible under ideal conditions. These include adequate moisture and fertility to support optimal development of reproductive seed stalks. Also, moderate temperature and humidity favor production and dispersion of viable pollen and promote the receptivity of silks to pollen during the flowering season.

Making a Good Grain Better

The prospect for much improved seed production began in 1981, when SCS’ Robert Dayton contacted Dewald. Dayton had discovered an eastern gamagrass plant with an unusual seed head: The mutant’s male flowers had become feminized and produced seed.

Dewald found that the seed count on each head of the mutant plants had increased by about 2,500 percent. But because the seeds were small, increased pounds of seed per plant ranged only between 300 and 500 percent.

From these so-called gynomonoecious plants with the sex-reversal trait, Dewald is screening for agronomic traits such as disease resistance, to develop new germplasm lines.

And some desired traits may be introduced to gamagrass from corn. But a viable cross between the two species can involve time-consuming and expensive techniques such as embryo rescue, says ARS cytogeneticist Bryan K. Kindiger, Woodward.

Often unsuccessful, embryo rescue involves cutting away part of a meager starch portion of a hybrid embryo that’s incapable of fully developing on its own and then artificially feeding the embryo with agar, a nutrient-rich plant gel.

Kindiger and retired ARS cytogeneticist Jack B. Beckett have found varieties of popcorn that can be used as a "bridge" between the two distantly related parents in this wide-cross breeding program. Plants from popcorn-gamagrass crosses often produce ears with more than 50 plump kernels—enough for continued research.

In other studies, Kindiger and Dewald have identified a refrigeration method that keeps gamagrass pollen viable for more than 10 days. Pollen of plants that differ in flowering dates thus becomes available to a greater diversity of crosses between strains or related species.

After many desired traits are bred into gamagrass, scientists hope to lock in genes for succeeding generations with genes for another trait, apomixis—asexual reproduction through seed. [See "Apomixis. It Could Revolutionize Plant Breeding," Agricultural Research, April 1993, pp. 18-21.] In apomictic plants, embryos grow from cells without being fertilized by pollen from males, thus preventing introduction of undesired traits.

Transferring desirable genes from corn to gamagrass has been made much easier by the advent of genetic engineering and high-tech innovations in conventional breeding.

A member of the Woodward team stationed at the University of Missouri-Columbia, ARS molecular geneticist C. Ann Blakey, used restriction fragment length polymorphism and polymerase chain reaction technologies to identify groups of genes in gamagrass that are remarkably similar to those found in corn.

"The genomic similarity between corn and eastern gamagrass may provide opportunities to endow either one with desirable traits of the other," she says.

Nutritionally, It’s First Class

The overall protein content of gamagrass grain is about three times that of corn and twice that of whole wheat, says ARS chemist Robert Becker of the Western Regional Research Center, Albany, California. In preliminary nutritional studies, he and his colleagues of the Center and the University of Nebraska found that gamagrass seed, with its abundant stores of unsaturated fatty acids—primarily linoleic acid—contained more than half again as much vegetable oil as ordinary corn.

The scientists also concluded that gamagrass seeds may have less of the trypsin inhibitor antinutrient than corn. Their studies showed that flour beetle larvae fed uncooked gamagrass flour supplemented with brewer’s yeast grew larger than larvae fed diets containing uncooked corn or whole wheat flours.

Having done preliminary baking studies, the ARS scientists at Woodward foresee the possibility of specialty breads from wheat-gamagrass flour blends.

Once a satisfactory way is developed to remove the hull surrounding the seed, gamagrass seed could be processed for flour or oil with technologies that are currently available.

The tightly bound hull also gets in the way of rapid germination of newly planted seed.

Dewald and Victor A. Beisel of Aaron’s Engineering, Fargo, Oklahoma, are developing a pneumatic dehuller. The device drives seeds against a slanted surface with compressed air to shatter the hulls. Mechanical dehulling vastly improves germination but still falls well short of hand-dehulling.

In other studies, Kindiger found that applying a 30-percent hydrogen peroxide solution to dehulled seed increased the number that germinated. Untreated seed has an average germination of less than 10 percent, while the treated averaged 70 percent.

In nature, variability in the degree to which hulls protect seed from fungi and insects ensures that at least some of the seed will germinate at a good time for the plant to survive.

However, "When we remove the hulls to increase germination rates, we run the risk of creating a feast for pests," Dewald says. He envisions artificially encapsulating dehulled seeds—perhaps with starch and agricultural chemicals—to help boost seedlings with a healthy start.

Meanwhile, commercial seed producers try to help seeds germinate quickly after planting through stratification—a wet-cool storage treatment for 6 to 8 weeks before shipment to the grower.

With research done by ARS and other public and private entities working together, eastern gamagrass has tremendous potential," says plant materials specialist Erling Jacobson of the SCS Midwest National Technical Center in Lincoln, Nebraska.—By Ben Hardin, ARS.