Within Clemson University’s vegetable breeding program, plant geneticists are uncovering traits that can help crops survive some of South Carolina’s toughest challenges: heat, disease and a changing climate. From disease-resistant leafy greens to heat-tolerant green beans, these discoveries are rooted in decades of grassroots seed collecting, patient trialing and collaborations across the state. Working closely with growers, Extension agents and farms large and small, this newly assembled research team is giving South Carolina a significant advantage in crop production — and strengthening the livelihoods of those who depend on it.
Above Photo
Back row: Stephen Kresovich, Robert and Lois Coker Trustees Endowed Chair of Genetics; Tom Bilbo, assistant professor and state vegetable entomologist; Karin Albornoz, assistant professor of postharvest; Sandra Branham, assistant professor of vegetable breeding and genetics; and Jerry Lee, director of agriculture at McCall Farms. Front row: Mark Farnham, research leader, U.S. Vegetable Laboratory (retired); Patrick Wechter, director of Coastal Research and Education Center; and Zack Snipes, area horticulture agent, assistant program team leader — horticulture.
Wearing a long-sleeved, gray T-shirt and blue Dickies pants, Joseph Fields walks across his fields with a noticeable limp, one that comes from working for decades on his family’s Johns Island, South Carolina, organic farm.
Limp or no limp, it doesn’t prevent Fields from outpacing everyone else down the rows of collard greens on an unseasonably cold early November day in the Lowcountry. It’s not until he stops to pull what appears to be a weed that everyone else catches up.
“A lot of people think this is a weed. But in the Caribbean, this is a delicacy,” Fields explains as he crunches on the leaves of the Callaloo plant, also known as green amaranth.
Fields’ affection for his land is unmistakable. His grandparents farmed here first, on a plot just across the road. He grew up behind a horse and a plow in the 1950s, working alongside his parents before taking over full-time with his wife, Helen, in 1973. Today, his operation is one of the largest African American-owned organic farms in the state.
“I love it,” says Fields, who grows everything from okra and strawberries to greens and spaghetti squash on about 30 acres. “I love watching stuff grow, harvesting it and selling it to the public. Farming, if you love it, do it. If you don’t love it, don’t do it.”
The lifestyle he loves is not easy. The Lowcountry may be famous for its hospitality, but its growing conditions can be downright hostile. Heat and humidity are relentless, insects thrive in every season, saltwater intrusion poses a significant threat, and disease pressure is constant.
“If you can grow a plant in Charleston, with the heat, the humidity, the pests, it’ll grow anywhere. And it’s proven that time after time,” says Pat Wechter M ’94, Ph.D. ’00, director of Clemson’s Coastal Research and Education Center.
The same love for farming can be seen in Earl Freeman, a fellow Johns Island farmer bundled up on a John Deere tractor as he and his workers scramble to harvest bell peppers and jalapenos before the night’s frost hits. But that doesn’t worry Freeman, who also grows collard greens, summer squash, tomatoes and okra.
“I’ve been farming since I was 4 years old. Seventy years. That’s all I’ve ever done,” he says with a big grin.
The Role of Clemson Extension
Zack Snipes M ’13, a Clemson Cooperative Extension Service agent, is one of the people trying to keep up with Joseph Fields on this brisk November day. A horticulture agent serving Charleston and Beaufort counties, Snipes has spent the past 15 years working and conversing with farmers in their fields, getting to know their families, their dogs’ names — immersing himself in their communities — to the point where farmers now look forward to his visits.
Snipes’ love for his job and his earned trust of the farmers show as he strolls with Fields, examining rows of collards. Snipes points out black rot, a bacterial disease that targets brassicas. It is one of the most significant and complex problems for growers. Later, he points to damage caused by diamondback moths before discovering one of the caterpillar culprits.
As a horticulture agent, the Clemson alumnus serves as a liaison between farmers, producers and research scientists at Clemson’s Coastal Recreation and Education Center — as well as the adjacent U.S. Department of Agriculture (USDA) Vegetable Laboratory.
Because of their relationship, Fields and other growers have been amenable to Clemson researchers using some of their acreage for field research. “Joseph has always welcomed me,” says Snipes, who declares Fields the most famous farmer on Johns Island. “He’s been very generous with allowing us to do trials on his land. Not everybody is like that.”
Down the road, Snipes stops to chat with Freeman, who takes a break from collecting his peppers. “When are you going to have my new tractor?” Freeman asks.
“When I hit the lottery, I’ll bring your money by,” Snipes quips back.
“I don’t want the money. I want a new tractor. And make sure it has four-wheel drive,” Freeman jokes.
Coastal REC: Analyzing Seeds, Breeding Plants
Researchers like Sandra Branham and Jenna Hershberger, who were hired in the past five years to work at Clemson’s Research and Education Centers, are another important part of the constellation working to boost the state’s farming industry.
When Branham was hired as an assistant professor of vegetable breeding and genetics, her position was new to Coastal REC, giving her the freedom to pick a project. After meeting with Extension agents, vegetable growers, processors and other stakeholders, breeding leafy green cultivars resistant to bacterial leaf blight and black rot became one of her major goals.
Branham longs for the day she can walk across acres of farmland throughout South Carolina and witness countless rows of luscious, heat-tolerant, disease-free collard and turnip greens. Seeing a sea of plants that continuously produce big, beautiful leaves that are easy to harvest, can withstand heat without bolting and are resistant to bacterial leaf blight — all while maintaining the flavor Southerners have enjoyed for generations — is her dream.
Branham has been working on developing such a cultivar for both collard and turnip greens. “I can’t wait to release something and see it on farms. That’s just going to be the best experience ever,” Branham says.
Branham’s work began with screening roughly 100 accessions of collards collected by a small but mighty team: former Clemson Extension agent Powell Smith, a mentor to Zack Snipes; Mark Farnham, a USDA vegetable breeder; and Ed Davis, professor of geography and environmental science at Emory and Henry University in Virginia.
Back in the winter of 2004, the three loaded up their Chevrolet SUV and began a two-day tour through Williamsburg, Horry, Charleston, Marlboro and Georgetown counties, going door to door to collect as many collard seeds as possible from local growers. They added the collected seeds to the USDA’s repository of brassica seeds in New York — part of a national living library that preserves thousands of crop varieties for future breeding and allows scientists to access and build on unique traits found in local fields.
Years later, Branham screened the seeds collected on that trip and made an important discovery: two varieties with strong resistance to bacterial leaf blight — a disease plaguing the region’s farmers. She has since worked to breed these two collards with varieties that bear traits desired by the state’s growers.
Jenna Hershberger, assistant professor of vegetable breeding and genetics, has also turned to the USDA seed bank to bolster the growth of a regional crop. Just a couple of years after Sandra Branham began her position at Coastal REC, Hershberger joined the Pee Dee Research and Education Center near Florence, South Carolina, in 2022 as its first vegetable breeder. Hershberger quickly became intrigued by work on heat-tolerant butter beans that former Extension agent Tony Melton had started.
Having to start from the beginning, Hershberger gathered seeds from a diverse collection at the USDA Germplasm Resources Information Network repository and through collaborations with public breeding programs in Delaware and California. The collection provided the diversity needed to address multiple breeding objectives simultaneously.
“We’ve been growing out hundreds of accessions at the Pee Dee REC to try to understand how they do in South Carolina,” Hershberger shares. “We’re assessing heat tolerance as well as many other traits that are important for commercial production. We’ve done three years now of trials.”
Her aim is to assess butter beans to eventually combine heat tolerance and disease resistance for commercial production in the region. She says it will take several years to develop new varieties for thorough testing. Branham is facing a similar situation in her work on a heat-resistant green bean — the same genus but a different species from butter beans.
Field Days at Coastal REC: Learning from Farmers
and Chefs
While researchers test crops in fields, they also test them with the region’s farmers at field days, where scientists, farmers and Extension agents come together to learn from one another. Each year, Coastal REC hosts an annual Brassica Field Day, where Branham learns directly from growers and producers by asking them to pick their favorite greens.
“I give each one a different color set of flags, and they flag the individual plants that they like,” she explains. She then asks participants to elaborate on what they like or didn’t like about the variety.
“They know the consumer,” she explains. “They know what people are willing to buy. They know what works in the processing plant.”
From field days, Branham learns that traits such as bigger leaves, upright plants and early-season vigor are important to growers.
Famed chef Benjamin “BJ” Dennis has also attended field days at Coastal REC, showing Branham the value of a chef’s perspective on brassicas, especially on traits such as appearance and flavor. The two have formed a collaborative relationship during the last two years, one that has benefited both.
Born and raised in Charleston, South Carolina, Dennis now resides in Okatie, outside of Beaufort. He began working in restaurants at 19 and has spent the last 15 years dedicating his work to the Gullah-Geechee culture through food.
“The last few years, I’ve been connecting back with the farmers in the area. That is why I have this deep connection with the work that Sandra is doing,” Dennis says. “We’ve lost so many of our heirloom seeds. Those seeds tell stories. The work is fascinating because it ties in with the type of work that I do as a chef.”
Branham has shared some of the collard varieties collected by Smith and his team with Dennis, who has passed them along to some of the local farmers he works with. One variety from Charleston County came from an 83-year-old woman whose mother passed the plant down to her. Dennis is particularly fond of this variety.
“If you look at this collard, it’s very different,” Dennis explains. “It’s not as big, but it’s super tender, super sweet. It cooks in like eight minutes. You can tell that collard green probably dates pre-Civil War.”
Where the Work Takes Root
Clemson’s Coastal and Pee Dee Research and Education Centers (RECs) are essential laboratories for the University’s vegetable breeding program. Located in two of South Carolina’s most productive agricultural regions, the RECs give breeders direct access to the region’s unique soils and climate — plus direct relationships with local farmers. These conditions allow researchers to test new varieties under true field conditions, gather feedback from farmers and ensure the traits they develop serve South Carolina agriculture.
The Vegetable Research Advisory Board
In addition to field days, Clemson researchers and agents gain valuable insights from growers through the University-established vegetable research advisory board. Among the board members are representatives from two of the state’s most influential farms, McCall Farms and WP Rawl.
McCall Farms owns a canning and freezing operation in Effingham, South Carolina, that consists of major national brands, including Glory Foods, Margaret Holmes, Peanut Patch Boiled Peanuts, Bruce’s Yams, Princella, Allens and Popeye. To manufacture these products, McCall Farms works with and sources crops from a network of farmers across and outside of the state.
Thomas Hunter ’06, co-president of McCall Farms, serves on the vegetable research advisory board and says the board and breeding program work hard to ensure stakeholder input is heard and to meet the agricultural needs of the state. Recognizing the value of this partnership, the company established the McCall Farms Vegetable Breeding Endowment four years ago — a $3 million contribution to support and enhance Clemson’s vegetable breeding program.
“At the end of the day, if we find a turnip green that’s got a high level of disease resistance, that’s great for McCall Farms, that’s great for the local farmer, that’s great for WP Rawl,” Hunter explains. “If we find a solution that solves a problem for multiple people, that is better than solving a problem for one person.”
In collaboration with Sandra Branham, Hunter is helping to develop a green bean that can stand up to South Carolina’s heat. Such a variety would translate to higher in-state yields and allow McCall Farms to source green beans from South Carolina instead of out of state.
Another member of the board, Charles Wingard ’87, is vice president of field operations at WP Rawl — a 100-year-old family-run farm that specializes in leafy greens and specialty vegetables. WP Rawl also has its own processing plant, where its crops are processed and distributed to major retailers across the country.
Sprawling more than 2,000 acres in Lexington, South Carolina, its headquarters seemingly take up most of the county, with vast fields of collard, turnip and mustard greens, kale, broccoli, parsley, cilantro, green onions, beets, and corn.
Like McCall Farms, WP Rawls graciously allows Clemson researchers to use several acres for trials, where researchers perform tests on commercial lots. Tom Bilbo, a University entomologist, is working to test the efficacy of sweet alyssum as a companion plant for collards; Dil Thavarajah, a professor of pulse quality and nutritional breeding, is testing kale and chickpeas.
Wingard is impressed with the collaboration among Clemson Extension and the breeders, pathologists, entomologists and weed scientists. But what impresses him most is their interaction with industry, including with smaller farms whose only Clemson connection is through Extension services.
“I see the Extension service reaching out to small farmers and collaborating with them and inviting them to production meetings,” Wingard reflects. “These smaller operations have serious issues. Their issues are just as important to them as mine are to me.”
Breeding Program Is on the Rise
Stephen Kresovich, Clemson’s Robert and Lois Coker Trustees Endowed Chair of Genetics, gets excited when he talks about the surge of interest in vegetable crops across South Carolina over the last decade. And both he and Paula Agudelo, who until recently was the University’s associate dean for research and director of Experiment Station, light up when they recount the crop of young hires brought in to boost the vegetable breeding program at Clemson.
From geneticists Sandra Branham, Jenna Hershberger and Trevor Rife to entomologist Tom Bilbo and pathologist Alamgir Rahman to postharvest biologist Karin Albornoz, Kresovich likes where Clemson is heading.
“We have a great group of young people that keep their nose to the grindstone,” Kresovich says. “I’ve been here a little over a decade, and the last five years, the vegetable team has really elevated itself. It’s filled with a lot of younger, talented people that are likely to have positive impacts over the next 20 years.”
“We didn’t really have a depth of expertise working on vegetable crops,” Agudelo adds. “For a while, we had gone too deep on field crops. This focus and the new people we are hiring are top-notch. I’m very excited about the progress I know we’re going to make in the next few years.”
Pat Wechter, who has worked with both the USDA and Clemson, gushes when talking about the team he oversees at Coastal REC.
“The impact that you can have with what we do here on so many lives — it’s not like putting a nut on a bolt. What we’ve done in just the last several years, it has impacted literally tens of millions of people.”
Pat Wechter M ’94, Ph.D. ’00
“I’ve done almost every job you can imagine,” says Wechter while standing among the tables and irrigation system he set up in one of the REC’s greenhouses. “Never have I had a job where I looked so forward to work every day. The impact that you can have with what we do here on so many lives — it’s not like putting a nut on a bolt. What we’ve done in just the last several years, it has impacted literally tens of millions of people.”
In the latest USDA Census of Agriculture, conducted in 2022, South Carolina was the nation’s top producer of collard greens, turnip greens and Southern peas while ranking highly in other categories. When the right people work together to breed and nurture crops for South Carolina’s climate, the state can hold its leads and begin to rise in other vegetable categories, continuing and strengthening its impact.
Reflecting on the vegetable team’s work, McCall Farms’ Hunter mentions something Paula Agudelo once told him: “Research on crops you’re going to be growing in a certain location is a lot like football: It’s the home-field advantage.”
Every team thrives with a home-field advantage. And this team is using South Carolina’s to improve the future of its state’s crops.
Marlon W. Morgan is a news writer/editor in the College of Agriculture, Forestry and Life Sciences. Photography by Sydney Lykins ’19, M ’22.
