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TECHNICAL SESSION: Population diversity of plant pathogenic nematodes

Susceptibility of Sweetpotato Varieties to Meloidogyne enterolobii and its Distribution in Eastern North Carolina
Tanner Schwarz - NCSU. Eric Davis- North Carolina State University

Meloidogyne enterolobii is an aggressive root-knot nematode species that has been detected in North Carolina within the last decade. In collaboration with the NCDA Nematode Assay Lab, root-knot nematode samples from sweetpotato, soybean, and tobacco grown in the eastern-half of North Carolina were analyzed using PCR to assay for the presence of M. enterolobii. This species has been detected in Columbus, Sampson, Harnett, Johnston, Wayne, Greene, Wilson, and Nash counties. Potential resistance to M. enterolobii in sixty selected sweetpotato [Ipomoea batatas (L.)Lam.] genotypes was evaluated in greenhouse experiments. 10,000 eggs of M. enterolobii were inoculated on each sweetpotato genotype grown in a 3:1 sand to soil mixture. Nine weeks after inoculation, roots were weighed, and nematode eggs were extracted from roots. Genotype susceptibility to M. enterolobii was assessed as the number of nematode eggs per gram of root. Susceptible genotypes included Covington averaging 3,730 eggs per gram of root, Beauregard at 4,263 eggs/gram root, NCDM04-001 at 19,613 eggs/gram root, and HiDry at 9,925 eggs/gram root. Resistant sweetpotato genotypes included Tanzania at 1.81 eggs/gram root, Murasaki-29 at 2.98 eggs/gram root, Bwanjule at 5.06 eggs/gram root, Dimbuka-Bukulula at 11.30 eggs/gram root, Jewel at 1.91 eggs/gram root, Centennial at 2.87 eggs/gram root, and Tib-11 with 10.77 eggs/gram root. We are collaborating with NC State sweetpotato breeders to incorporate the observed resistance to M. enterolobii into commercial sweetpotato cultivars.