Bigger, better food … and more of it

UGA researchers explore ways to modify foods to get the highest quality products and the largest yield

Print
Email
PDF
Share
Bigger, better food … and more of it

Muscadines ripen on the vine in a Georgia vineyard. Georgia grows more of the grape than any other place in the world. UGA crop breeders are working to improve disease resistance, yield and edibility.

Photo by: Dot Paul

James Lee Adams stands tall. At 6 feet 3 inches he is dwarfed only by the massive irrigation system used to water the crops on his farm in southwest Georgia. Today, as most days, he is covered in soil. Dirty paw prints from his four-legged family member, Doc, hint that the two have been on their daily trek around the farm.

“She’s gonna get both of us,” he says, warning the Jack Russell terrier that his wife Sue will not be pleased with the state of their clothes.

“I’m one of the best there’s ever been,” he says of his career as a farmer. “Dizzy Dean said if it’s the truth it ain’t bragging.”

Adams’ success as a farmer was recognized by the industry when he was named the Southeastern Farmer of the Year in 1992 and 2000.

James Lee Adams stands under a center-pivot irrigation system in one of his fields. Adams makes his way around the 2,500-acre Camilla farm with his farmhand, a Jack Russell terrier named Doc.

Much of his success, Adams says, is due in large part to the plant breeding programs at the University of Georgia.

Research conducted by UGA peanut breeder Bill Branch has led to even healthier plants and increased yields for Georgia farmers. His newest runner variety, Georgia 06G, has a high resistance to tomato spotted wilt virus and has produced yields over 7,000 pounds per acre, which gives it an advantage over lower-yielding varieties.

“When I started farming in 1969, if you made a peanut yield of 2,000 pounds an acre that was outstanding,” Adams says. “In 2000 we harvested 6,000 pounds an acre.”

From the beginnings of plant breeding until a couple of decades ago, breeders modified crops by crossing many varieties together and conducting large field trials, looking for plants that were higher yielding or had better quality.

Today, breeders have an arsenal of new tools available, most of which are spinoffs from the Human Genome Project.

Breeders now use DNA sequencers, computers and other molecular diagnostic tools that allow them to improve quality and boost yields more efficiently for Georgia farmers, which means more money for the state.

In Georgia, agriculture accounts for $65 billion of the state’s economy, making it the largest economic driver in the state.

“When you look at a seed catalog and see ‘new and improved’, we are the people who new and improved it,” says Wayne Parrott, a geneticist and professor of crop and soil science with the UGA College of Agricultural and Environmental Sciences.

Wayne Parrott checks on new cultures in a plant growth room. New plant material from his lab begins in a dish before being planted in soil and moved to a greenhouse.

“This is what new and improved does, it contributes to efficiency, profitability and sustainability.”

Adams has been farming since 1969 when he bought land in southwest Georgia from his father. Over four decades he and his family have grown pecans, peanuts, cotton, corn, soybeans and hay and raised cattle, poultry and even alligators on the more than 2,500 acres he owns in Camilla.

“I’d argue every one of our crops has been genetically modified for the last thousand years,” Adams says. “We have always selectively bred for traits. All we’ve done is found an additional tool to more precisely modify the crop and control it and make sure it has the attributes we really want.”

The term “genetically modified“ can be confusing. Plant breeders and farmers consider genetic modification to be cross breeding within a species and gene selection. Often the public confuses genetic modification with genetic engineering, which means moving genes between species. Genetic engineering has been important to Georgia’s cotton, corn and soybean crops.

Nevertheless, says Parrott, “99.9 percent of genetic modification to plants does not involve genetic engineering at all.”

Peggy Ozias-Akins gently removes the stamens from a peanut flower so she can fertilize the plant with the pollen from a desired male. Typically self-fertile, altering the mechanism will produce a new variety, perhaps one with fewer allergens.

Using tweezers and a magnifying lens, Peggy Ozias-Akins removes the stamens from each flower on the peanut plant. She then collects the pollen from a desired mate to create new offspring. A molecular geneticist and professor with the College of Agricultural and Environmental Sciences on the Tifton campus, Ozias-Akins is stopping the peanut from self-pollinating in hopes of creating a new variety that will be allergen free.

Most allergic reactions occur from the three seed storage proteins found in the legume.

She is collaborating with medical doctors to determine the human response to the new peanut type to see if the absence of the proteins eliminated the allergenicity.

Her hope is to breed peanuts with less of the storage proteins present so after several years the allergen will not exist. She also is searching for a natural mutation that silences the expression of genes causing the allergic reaction.

“We can look at a piece of a seed and determine what the seed will become,” Ozias-Akins says. “There are genetic markers—a piece of DNA that has been studied and shown to be linked to a particular trait. Rather than screen for a trait, which can be time consuming and destructive to the plant, we can screen for the marker from a seed chip.”

Research critical to the state’s pecan growers also is being conducted at the UGA campus in Tifton. Georgia farmers harvested 100 million pounds of pecans last year, bringing in $300 million. China bought 90 million pounds of pecans last year. With China’s increased interest in the nut, more Georgia farmers are starting orchards and looking for superior trees.

“Plant breeding, like most of science, is generally based on incremental gains which add up over time,” says Patrick Conner, an associate professor and pecan breeder based on the Tifton campus.

New pecan cultivars are chosen based on whether they produce a larger nut or mature more quickly. Conner’s program is searching for higher resistance to pecan scab so growers can spray less of the expensive fungicides needed to control the disease. The development of new cultivars with high levels of resistance will make the pecan industry more environmentally sustainable and more profitable for the grower.

A cabinet filled with pecan specimens from around the world sits in Patrick Conner’s office. Georgia’s primary pecan variety is Stuart. Conner is working to develop the next great nut—one resistant to pecan scab.

“In traditional plant breeding you are doing what happens in nature, except you are selecting the parents instead of leaving it up to the wind and you are selecting the progeny instead of letting nature select,” Conner says.

Muscadine grapes are another area of research for Conner. Georgia is the world’s top producer of the sweet, thick-skinned grape, typically eaten fresh or made into jam, jelly, juice or wine. Muscadines have become popular in recent years as research has shown them to be high in Resveratrol, an antioxidant, which can stave off degenerative diseases.

Conner developed a self-fertile variety of the grape, called Lane, which is more productive than female varieties and ripens two weeks earlier. Conner now is attempting to create a variety without seeds and one with a thinner, tastier skin.

“I was always taught that plant breeding is an art and a science,” he says. “The science is the genetics. The art is being able to eyeball a crop and see the potential, to see the colors and taste the fruits just hoping the next one is going to be the one that is really special.”

Aboard a self-guided bucket truck, Conner hand pollinates each bloom on the pecan trees in his orchard. The buds are bagged to protect them from wind-pollination. The process takes every minute of daylight from March to August.

Genetic modification is not limited to plants. UGA researchers also look at ways to breed animals to become more disease resistant.

“Disease and death in livestock is a serious problem, particularly in underdeveloped countries,” says Steve Stice, a Georgia Research Alliance (GRA) Eminent Scholar in Reproductive Physiology and UGA professor of animal and dairy science.

Stice and colleagues are developing cellular adaptive resistance, a term he coined for a process that incorporates stem cells and results in disease-resistant livestock. The research team can perform genetic screening and testing of animal stem cells that are naturally resistant to a disease in a dish, speeding up the selection process for desirable disease-resistant genetic traits. He is currently using the technology to combat Newcastle Virus, which kills about one-quarter of the chickens in sub-Saharan Africa every year.

“We want to provide a new way to create disease-resistant animals using new technologies to combat disease problems,” Stice says. “This process will produce animals with natural resistance to specific diseases that will need less veterinary care and will significantly reduce livestock mortalities.”

Bovine diarrhea virus has a major economic impact on Georgia cattle farmers. A breed of cattle resistant to the virus would be better for farmers and the animals.

“The approach is a platform technology that will apply to all types of animals,” he says.

Genetically modified organisms can mean healthier food too—like a leaner cut of meat.

Sammy Aggrey, a quantitative and molecular geneticist in poultry science, is mapping the chicken genome to unlock the code for a better bird.

Chicken accounts for 40 percent of the meat produced in the United States. Obese birds yield less meat, and smaller breast muscles mean less money at the market. Reducing fat and increasing breast muscle could improve production efficiency while meeting consumer demand for a leaner cut of meat, Aggrey says.

“Feed constitutes 70 percent of production input,” Aggrey says. “If we could utilize less feed and yield the same or greater amount of protein we would increase efficiency. Animals that use feed more efficiently are less fat, so we will simultaneously correct two problems.”

Meanwhile, breeding work continues at UGA. U.S. farmers now produce 50 percent more food on the same amount of land as they did just 30 years ago. To meet projected food needs of the future, they will need to double yields on that land, and they will have to do so without additional water or pesticides.

“The challenges are great, but I am confident we will be up to task,” says Scott Jackson, a GRA Eminent Scholar in Plant Genetics and a UGA professor of crop science. “However, we will need all the tools available, and breeding is a major one.”