Meloidogyne incognita is the most common root-knot nematode found in agricultural regions worldwide. It can cause severe damage to many crops including sweetpotato storage roots, causing them to be unmarketable and resulting in significant yield losses. Identifying resistant crop varieties is one of the most effective ways to manage M. incognita. To identify germplasm with resistance to M. incognita, 47 sweetpotato accessions obtained from the USDA germplasm repository were screened in replicated greenhouse assays. ‘Beauregard’ was used as a susceptible control and ‘Regal’ as a resistant control. Sweetpotato slips containing 3 nodes each were planted in an autoclaved 1:1 mixture of sand and potting mix in Deepot D25L containers and arranged in a randomized block design, with 2-3 replicates per an accession. Two weeks after planting, each plant was inoculated with 10,000 M. incognita eggs. Eight weeks after inoculation, plants were harvested and rated for fibrosity, galling, number of egg masses, and eggs per gram of root. Resistance was defined as accessions with mean galling ≤ 10% and mean eggs per gram of root ≤ 500. Based on these criteria, 12 accessions were identified as having resistance to M. incognita.
