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Research Magazine > ARCHIVE > Summer 01 > Article

Pearls of Great Promise
by Dan Rahn
illustrations by Jay B. Bauer

Magicians have long astounded people by making things disappear. But scientists in South Georgia are trying to do the opposite: They’re working to make an invisible crop appear in fields throughout the state.

It’s not a simple trick. They have to convince thousands of farmers to think of the crop — pearl millet — in ways they’ve never thought of it before. They also have to convince potential markets for millet statewide to switch from other grain crops. And they have to accomplish both feats at the same time.

Doing that may seem more miracle than magic. Yet conditions in Georgia may well be perfect for pearl millet to become one of the state’s biggest crops, a rival even of cotton and peanuts.

An invisible crop
Georgia farmers are familiar with pearl millet, but not as a major grain crop. They see it only as a forage crop, as something their animals eat as it grows in their fields. Though U.S. farmers grow as much as 2.5 million acres of it, the crop is invisible in state and national farm statistics.

“As a forage crop, pearl millet is grown and used on the farm,” said Jeff Wilson, a plant pathologist with the U.S. Department of Agriculture’s Agricultural Research Service. “It’s not harvested, weighed or sold. Officially, there are no records of it.”

Wilson is one of a team of ARS and University of Georgia scientists who have been studying pearl millet as a forage crop for about 60 years at the UGA Coastal Plain Experiment Station in Tifton. For roughly half that time, ARS geneticist and UGA adjunct professor Wayne Hanna has carried on the research.

About 15 years ago, though, Hanna and others in Tifton began experimenting with pearl millet as a grain crop. They could see the crop becoming uniquely suited to Georgia in the 21st century. It was a fascinating vision, considering the plant’s origins.

Pearl millet (Pennisetum glaucum) is native to the western edges of the Sahara Desert. With long, broad leaves, it’s also known in this country as cattail millet for its dense, round spike. Its more common name comes from closer
inspection of the spike, which is studded with pearl-like grains.

The plants that now grow on 50 million acres in Africa and India are hardly invisible there. They grow 10 to 12 feet tall, and they’re everywhere. “They use the grain for human consumption,” Hanna said. “They feed the leaves to their oxen, they build their houses and fences with the stalks, and they use the roots as fuel for cooking.”

Pearl millet is a nutritious grain, high in protein and calcium. In the countries where it’s a staple crop, it serves well the needs of the people who grow it. “I could probably sell a few tons of it here [in the United States] for health foods,” Hanna said.

But rather than being merely a specialty crop for health foods, a number of factors are coming together at just the right time for pearl millet to offer extraordinary potential to Georgia farmers.

Growing water demands
“Georgia’s population is growing and placing increasing pressure on the state’s water resources,” Wilson said. “And whenever food production competes with people for water, the water will always go to the people.”

With its roots in the Sahara Desert, pearl millet can give the advantage back to the farmer. “That’s where it really fits here,” Hanna said. “Pearl millet can produce a grain crop without supplemental moisture.” Even in a dry year and without irrigation, he said, pearl millet can yield 100 bushels of high-protein grain per acre.

In comparison, Georgia farmers who didn’t irrigate their corn in the dry summer of 1998 averaged only 26 bushels per acre. Thousands of acres went unharvested. Even in good years, nonirrigated corn averages only 80 to 90 bushels per acre, figures pearl millet could easily double.

“Over thousands of years, pearl millet evolved to respond very quickly to moisture,” Hanna said. “It germinates very quickly. And even after it germinates, it will go into a dormant stage in a drought and then respond quickly again when rain comes along.”

A crop that grows well without the aid of irrigation is likely to get the attention of Georgia farmers, especially after three years of a parching drought.

“During the past 100 years, only the droughts of the 1920s and 1950s have had the agricultural and hydrological impact of the current Georgia drought,” said David Stooksbury, state climatologist and an engineering professor with the UGA College of Agricultural and Environmental Sciences (CAES).

The UGA Automated Environmental Monitoring Network’s monitoring station near Midville, Ga., recorded a water-balance deficit of 57.4 inches from May 1, 1998, to mid-October 2000. In other words, the soil there lost almost
5 feet more moisture to evaporation and transpiration than it gained through rainfall. The deficit figures were similar for other stations.

Despite periodic months of above-normal rainfall, the prospects for long-term improvement aren’t promising, Stooksbury said. “It appears that after nearly a half century of relatively tranquil climate patterns, Georgia has returned to a more normal pattern.”

“This means that Georgians can expect greater year-to-year variations in temperature and precipitation,” he said. “The need for dryland farmers to diversify their cropping patterns will increase with the increased climate variability. Pearl millet is part of the response.”

Millet-ready market
The growing needs for water in a state increasingly conscious of water resource limitations were only one part of the scientists’ vision for pearl millet. They knew they needed a market for the millet. And Georgia has the biggest one they could imagine.

“We produce 23 million pounds of chicken every day,” said Abit Massey, executive director of the Georgia Poultry Federation. “It takes about
2 pounds of feed for each pound of chicken. And corn and soybeans are the major ingredients of that feed. All my life I’ve heard that farmers should produce for a market. I don’t know of a better market than poultry. It may be the ideal market for pearl millet.”

At the moment, almost all the corn and soybeans Georgia farmers feed their 1.24 billion chickens each year is shipped into the state from the Midwest.

Early findings on pearl millet as poultry feed are encouraging. “We’ve had wonderful results,” said Adam Davis, a UGA poultry nutrition and physiology researcher who conducted the first tests. “The initial studies were much better than we expected. Pearl millet replaced all of the corn and some of the soybean meal. That’s exciting.”

In typical poultry rations, corn provides the energy chickens need, but Davis said they also need soybean meal to meet their protein requirements. A normal poultry ration has about 50 percent to 60 percent corn. But the state’s corn crop is just a drop in the bucket of what Georgia poultry farmers buy. “I would be shocked if [the entire Georgia corn crop] were 1 percent of the corn we use here,” Davis said.

“We were looking at replacing some of the corn with pearl millet,” he said. “But we found we could replace all of the corn. The energy content in pearl millet is just as good, and the protein content is much higher.”

Corn normally has about 8 percent protein, Davis said. But for their early studies, the pearl millet sample they were supplied had 14 percent protein.

A key question for Davis is whether the protein content will be consistently high. That, Hanna said, depends on the amount of nitrogen the crop gets. Unfertilized and under the worst conditions, pearl millet’s protein levels may be too low. But under normal conditions, Hanna said he believes it will stay at 12 percent or higher.

He stressed, though, that the preliminary studies were limited by a short supply of pearl millet. “We’ve been limited to studies of chicks over one to two weeks,” he said. “We want to do more complete studies.”

UGA animal scientist Gary Hill studied pearl millet and also found the grain well-suited to newly weaned calves because of their high protein needs. “The high protein content and balanced amino acid profile of pearl millet grain make it better suited to poultry and swine diets,” Hill said. “But it can be used efficiently in beef and dairy cattle diets.”

If early studies bear out, Massey said, pearl millet and poultry could become a fruitful union. “We looked at this a while back with help from the university, and we found that if Georgia could produce enough corn and soybeans to supply the state’s poultry, it would make corn and soybeans the two major crops in Georgia,” he said.

But the state’s farmers can’t grow those crops competitively with Midwestern farmers, who typically average 140 to 150 bushels of corn and 40 to 50 bushels of soybeans per acre.

“Meeting poultry-ration needs could make pearl millet one of the major crops in the state,” he said. “The demand is there, it’s year-round and it’s growing every year.”

Science for the times
Of itself, though, casting pearl millet before poultry, even in a perfectly drought-conscious state, still wouldn’t make it a miracle crop. But the crop-climate-market combination also has come together in the only place where scientists can give it the proper nudging.

“Until recently, there were three pearl millet breeding programs in the United States,” Wilson said. “There was one in Kansas, one in Nebraska and one in Tifton. But active plant-breeding research is now being conducted only at Tifton.”

Pearl millet is simply not, as yet, a high-profile crop. The funding for what has been seen as a simple forage crop has fallen away. “We have had to struggle for [funding] in our country,” Wilson said.

The university’s CAES, though, has shared the ARS scientists’ vision for the crop. And scientists around the world increasingly are turning to the Tifton researchers. Georgia has become one of the best places in the world to learn about pearl millet.

And that’s an important part of the crop’s promise. Georgia farmers can’t plant Africa’s 12-feet-tall, hand-harvested varieties. U.S. agriculture is highly mechanized, and nobody makes machinery that will harvest millet that tall. The scientists must consider height and other factors to develop a variety that will work in American agriculture.

“We worked on dwarfing and making earlier [faster-maturing] hybrids first,” Hanna said. “Then we had to get rust resistance.” The scientists learned about the tenacity of the fungal disease, pearl millet rust (Puccinia substriata var. indica), the hard way when they released their first pearl millet hybrid, HGM-100, a decade ago (see Rust Resistant?).

“HGM-100 was a good hybrid, but no variety is perfect,” Wilson said. “Although it was resistant when it was released, the fungus changed quickly to overcome the resistance. And once it was susceptible to rust, farmers were too vulnerable to produce a profitable crop.”

More durable rust resistance wasn’t easy to come by. Pearl millet rust, he said, has several ways to overcome resistance:

  • By occasional mutations in the millions of spores produced in a field.
  • By spores from dead pearl millet leaves infecting eggplant, then creating new spores that infect the pearl millet. In the recombination, or genetic exchange (and sometimes change), of chromosomes, new types of the rust emerge.
  • And possibly by new spores blown first by trade winds from West Africa into South America, the Caribbean and South Florida and then by tropical storms farther into North America.

“This is speculative,” Wilson said, “but not an unreasonable assumption. Similar transoceanic spread has been shown to occur in a few diseases. But it hasn’t been documented with pearl millet rust.”

Closing the deal
With Wilson’s help, Hanna eventually bred a new, more complex combination of rust resistance genes into pearl millet hybrids. Hanna’s new hybrids, for which some seeds will be available to farmers in 2002, will have more going for them than improved rust resistance.

With larger seed spikes, they produce much higher yields of grain.

They’re shorter — only 4 to 4.5 feet tall, a full 2 feet shorter than earlier hybrids. The shorter stalks will allow for easier mechanical harvesting.

They flower earlier, in 45 to 48 days. (Allowing for drying time in the fields, the new hybrids can be harvested 80 days after planting.)

Together with the improved rust resistance, the compact growing season will make these hybrids incredibly flexible on Georgia farms. They can be grown before or after other crops in the same year and in annual rotations with several crops, including cotton, peanuts, wheat and canola.

“Pearl millet can be planted from mid-April to the second week in August,” Hanna said. With the long planting season, Georgia farmers can plant double crops of pearl millet back-to-back.

“The newer hybrids are much better,” Wilson said. “But they’re still not perfect.” Scientists are still working on the remaining imperfections. A number of diseases, including pyricularia leaf blight, stalk rots and grain molds, can damage the crop.

Even birds can be a problem. “They gave us a thrashing in our test plots,” Hanna said. “But when we had a few thousand acres out there in the early ’90s, we didn’t have a bird problem then.”

Weeds could be bothersome, too. Farmers have no federally approved chemicals for controlling weeds in pearl millet, Hanna said. But he’s confident weeds can be overcome.

Among insect pests, chinch bugs are the most damaging. “They’re a very important limiting factor in pearl millet production,” said UGA entomologist Randy Hudson. “But they’re manageable. We’ll have strategies to manage them by the time the new hybrids are available.”

Hudson is also the first coordinator of the new CAES Emerging Crops and Technologies Initiative (see “Emerging Crops” below), which fits pearl millet like a glove. “If you look at potential new commodities,” Hudson said, “of all the ones we’ve worked with, the one that shows the best potential is pearl millet.”

As the coordinator of the emerging crops initiative, Hudson is deeply concerned with the final, crucial step. He knows it’s not a matter of which comes first, the chickens or the pearl millet: They both will have to come at the same time.

For pearl millet to become the new crop it can be in Georgia, there will have to be farmers willing to grow it, grain elevators willing to store it and poultry producers willing to buy it and blend it into poultry rations — all in the same year.

“We’ll have to develop the infrastructure,” he said, “and that’s going to take an alliance between the growers, elevators and poultry producers. When the seed is available, we’ll have all the other elements in place. We have to bring the infrastructure together then, and we hope to be able to do that.”

Wilson is confident the state’s farmers, perhaps the most hesitant of the main elements, will be quick to plant pearl millet. “When we released HGM-100, that was a radical thing,” he said. “And yet in the first year after we released it, growers planted 35,000 acres. That says something about it.”

For more information, access the USDA-ARS Forage and Turf Research Unit at http://sacs.cpes.peachnet.edu/fat.

Dan Rahn, a former English teacher and newspaper reporter, is an extension news editor for the UGA College of Agricultural and Environmental Sciences. He has bachelor’s and master’s degrees in English education from Georgia Southern University.

Jay Baeur, an art coordinator for the UGA College of Agricultural and Environmental Sciences, has a bachelor’s degree from the Art Academy of Cincinnati. He has exhibited work in numerous galleries and has been commissioned by private collectors.


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Georgia-grown pearl millet may soon replace Midwestern corn and soybeans in the chicken feed that nourishes the state’s $3 billion poultry industry.