2025 - Your Commission at Work

YOUR RESEARCH COMMITTEE AT WORK

IMPACT STATEMENT

North Carolina is the largest producer of sweetpotatoes in the nation, and new varieties are always sought to address disease and pest problems, as well as ever-changing market conditions. The emergence of Meloidogyne enterolobii threatens NC’s sweetpotato industry, and we expect that new varieties will become a critical component of the management strategies required to control this pest. The NCSC has supported the Sweetpotato Breeding and Genetics program’s efforts for many years, and this has enabled us to establish a large and dynamic program focused on developing new varieties adapted to NC’s growing conditions. We have had success: Covington, released in 2005, now accounts for ca. 90% of NC’s acreage. Based on the 2023 USDA NASS estimate of 77,800 acres of sweetpotato harvested in 2023 and a farm gate value of ca. $305 million, Covington accounted for ca. $274 million in NC farm-gate receipts. Given the wet harvest conditions in 2017, 2018, and 2020, NC has done very well avoiding major losses by using the flood-tolerant Covington. However, we are always looking for improved varieties for NC farmers, and the continued support of the NCSPC helps us to maintain our extensive and relevant variety development efforts. We released purple-fleshed clones ‘Purple Splendor’ and ‘Purple Majesty’ to fit into the market of ‘Stokes Purple’. Both have performed very well, but they are specialty varieties and will not replace Covington. We are working hard to incorporate GRKN and SRKN resistance into new varieties that can replace Covington and enable NC’s sweetpotato growers to retain and/or expand into new markets.

TITLE: Research Towardsa Rapid, Species-specific, Field Deployable Test for GRKN and Advancement of Molecular Diagnostics for Soil and Sweetpotato Samples of molecular diagnostics for soil and sweetpotato samples

LEADER(S): Adrienne M. Gorny

IMPACT STATEMENT

The GRKN poses a very significant threat to North Carolina sweetpotato production due to its ability to overcome host resistance used for other root-knot nematodes in cultivars such as ‘Covington’, the severe symptoms it produces, and its regulatory status in many European markets. It has also been shown to be more difficult to manage through chemical nematicides and cultural practices. Early, rapid, and accurate I diagnosis of GRKN-infected sweetpotatoes would allow sweetpotato producers to take appropriate action at the farm or packing house to mitigate the impact of this nematode on shipments of sweetpotato. However, because GRKN is closely related to other species of root-knot nematode (such as Meloidogyneincognita), DNA-based molecular assays are required to distinguish the species. Currently, the NCDA&CS performs a PCR assay to accomplish this detection and diagnosis.

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