CHARLESTON, S.C. – Visitors to the 2021 Field Day at the Clemson University Coastal Research and Education Center (CREC) had an opportunity to see the latest research to help South Carolina vegetable growers overcome issues that may threaten their bottom line.
Grafting is one tool the researchers use to help improve existing plant lines. Richard Hassell, former professor, physiologist, Clemson Cooperative Extension Service vegetable specialist, is grafting pepper scions onto E-3 rootstock in hopes of developing peppers with Phytophthora crown and root rot resistance.
“We’re excited about what we’ve found so far,” said Hassell, who retired at the end of 2020. “We believe soon we’ll have a product that will work well for South Carolina growers.”
Until a resistant variety is found, Hassell said growers can take steps to minimize root rot appearing in crops, including crop rotation, soil management and water management.
Fusarium wilt is another disease that can threaten vegetable growers’ bottom line.
“Fusarium wilt of watermelon is the most widespread and destructive disease of watermelon in the southeastern United States and other areas of the world,” Keinath said.
Following a test of several cultivars, Keinath and his team found the cultivar Fascination when attached to Carolina Strongback rootstock showed resistance to fusarium wilt. Grafted Fascination is available for growers to buy.
In addition to his grafting study, Keinath also talked about work he is conducting on beets to determine susceptibility to Phoma and Cercospora leaf spots.
Other presentations about grafting studies included one by graduate research assistant Sean Toporek, who is grafting cantaloupe to control downy mildew. Pat Wechter, USDA-ARS research plant pathologist, talked about graft incompatibility in muskmelon using Carolina Strongback rootstock.
Visitors also learned about a study Sandra Branham, assistant professor of vegetable breeding and genetics, is conducting with green beans to try to extend the growing season and protect the crop from the heat. Branham’s study involves 50 commercial varieties and 300 ex-PVP (plant variety protection) strains.
Plant variety protection is a tool plant breeders use to protect their innovations. This protection is granted through the United States Department of Agriculture Agricultural Marketing Service (USDA-AMS) Plant Variety Protection Office. Once protection is granted, owners have exclusive legal rights to market and to exclude others from selling their varieties for 20 years, 25 years for woody vines and trees. The legal protection has expired for ex-PVP varieties.
To determine which varieties are best suited to withstand South Carolina’s hot summers, Branham will count and weigh beans from each plot at the end of the growing season.
Gursewak Singh, a graduate research assistant, talked about his cover crop anaerobic soil disinfestation (ASD) study “Using cover crops to facilitate ASD.” In his study, Singh is looking for carbon sources and is using sorghum and sun hemp as cover crops.
Matthew Cutulle, a weed scientist, discussed issues involving herbicides in tomato and other vegetables, such as environmental impacts on herbicide carryover and injury. Cutulle said microbial activity has increased in 2021 making it “an usual year” for herbicides.
In an update on hemp, Brian Ward, an organic vegetable specialist and assistant professor at the Coastal REC, said one variety being looked at for growing in South Carolina is Hurricane Hemp – Florence. This variety was developed after Hurricane Florence leveled much of the hemp crop in 2018 and farmers lost about 15% to 20% of their yields. This line has passed two years of testing in South Carolina and now Clemson researchers are using “basic science” to determine production requirements such as plant spacing, fertility and planting dates, “so that yields can be optimized, upfront costs can be reduced and profits can be greater,” Ward said.
As for the Guava root-knot nematode, Zack Snipes, Clemson Extension area horticulture agent, told field day participants Extension agents are conducting surveys to raise awareness about this pest. The Guava root-knot nematode was detected in Darlington County during a routine survey by Clemson University’s Department of Plant Industry (DPI) in September 2017 and poses a threat to the state’s economy.
In addition to research, vegetables grown at the Coastal REC also serve the community by being donated to the James Island Outreach. Scott Graule, director of the Outreach, talked about the fresh produce his organization receives from the Coastal REC and how it benefits his clients.
“Most of the time our clients get canned goods,” Graule said. “There is a need for fresh produce and when we do get fresh produce, our clients take it so quickly, it doesn’t have time to spoil.”
Vegetables are collected by volunteers as part of the Outreach’s Fields to Families program.