A sweet potato line with excellent eye appeal and good disease resistance is poised to be released to growers soon, LSU AgCenter sweet potato breeder Don La Bonte said at a field day on Aug. 16.
About 100 producers and industry representatives attended the event at the AgCenter Sweet Potato Research Station, where they heard from experts on variety development, management practices and industry updates.
La Bonte said the new line, currently called LA 13-81, has traits that appeal to both consumers and producers. It has a showy, bright red skin that maintains its sheen through harvest and yields well in different soil types.
If released, LA 13-81 would join a stable of other AgCenter varieties — such as Orleans, Bayou Belle and Evangeline — that offer alternatives to the Beauregard variety, the longtime industry staple in Louisiana.
La Bonte also is continuing work to develop varieties that mature earlier and are more resistant to diseases and insects.
“In the retail trade, having several different types of sweet potatoes on the shelf is important to increase marketing potential,” La Bonte said.
Most Louisiana sweet potatoes are sold for processing rather than the fresh market, said AgCenter extension associate Myrl Sistrunk.
Some farmers are having to look for new outlets for their crop after a sweet potato canning facility in Arkansas — the closest to Louisiana — shut down last year, he said.
Louisiana had about 9,300 acres of sweet potatoes in 2017, and Sistrunk expects that number to drop by 500 to 800 when acreage is tallied this year. Some growers have cut back on acreage or left the business altogether, he said.
Field day attendees also heard from AgCenter plant pathologist Chris Clark about two potential threats to their crop: the guava root-knot nematode and black rot.
While the aggressive nematode — which was found for the first time in Louisiana earlier this year — has been in the news lately, black rot is perhaps a bigger concern in the short run, Clark said. The disease had not been a concern in Louisiana since the 1970s until it resurfaced recently.
“This is something that can blow up, and blow up in a short time,” Clark said of the disease.
Black rot can be managed with crop rotation, buying “clean” virus-tested seed and treating them with effective fungicides, and cutting plants 1 inch above the soil when collecting slips.
While the nematode is not as easily controlled, it so far has been contained in Louisiana to a single field in Morehouse Parish where it was identified. Growers who suspect they have it should send samples to the AgCenter nematology lab, Clark said.
Two international groups attended the field day to learn more about Louisiana sweet potato production practices.
Kaye McAllister, a researcher at the University of Guyana, said the white flesh sweet potato varieties are most common in her country. McAllister is working with the Guyana National Agriculture Research and Extension Institute through a collaborative program with the University of Arkansas at Pine Bluff to improve technology in sweet potato production and address disease and pest challenges.
Australian seed producers Eric and Kristie Coleman are licensed sweet potato seed distributors with the AgCenter and planned their visit primarily to attend the field day, speak with scientists and look at research results.
“Even though we are in a different production environment, you always learn a lot from looking at production practices in another environment,” Eric Coleman said.
Rogers Leonard, AgCenter associate vice president, said the AgCenter sweet potato program is unique in that it involves every aspect of the crop, from variety development and seed production to harvest and economics. The AgCenter takes a similar approach with sugarcane and rice, which also are important Louisiana crops.
“Sweet potato remains a signature crop in Louisiana,” Leonard said.
The field day featured a number of other presentations:
- AgCenter agronomist Arthur Villordon said holding slips up to three days in a temperature-controlled environment can improve plant stands in some varieties by minimizing stress and allowing the root to emerge before planting.
He also discussed a study that indicated some varieties are better at scavenging for phosphorous than others, meaning producers may be able to save money by adjusting application rates accordingly.
- AgCenter research associate and doctoral student Cole Gregorie said planting sweet potato slips horizontally instead of vertically can increase yield and the amount of No. 1 potatoes harvested.
Horizontal planting improves root uniformity, increases water availability and reduces nutrient depletion zones, Gregorie said. He also talked about the advantages of subsurface irrigation systems, which have lower maintenance and labor costs than surface systems.
- AgCenter research associate and doctoral student Theresa Arnold described the process of identifying possible new varieties. Just a few make the cut after being culled from an initial pool of about 30,000 seeds and extensively evaluated.
- AgCenter Sweet Potato Research Station coordinator Tara Smith said foundation seeds are now being produced at four locations to spread out risk, and sweet potato entomology trials are being conducted the AgCenter Dean Lee Research Station near Alexandria.
- AgCenter weed scientist Josh Copes said it’s important to use residual herbicides in sweet potatoes, and new products may be available soon.
- AgCenter pesticide safety coordinator Kim Pope Brown said farmers need to ensure they comply with updated the Worker Protection Standard rule. Louisiana farmers must complete a course offered by the AgCenter if they want to train their own workers on safely handling pesticides, which is required annually.
- Kay Rentzel, United States Sweet Potato Council executive director, said a consumer research project is underway to collect information to improve industry marketing and educational outreach.