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United States Department of Agriculture

Agricultural Research Service

Title: Stability of Resistance to Southern Root-Knot Nematode in Bell Pepper (Capsicum Annuum) at High Temperatures

item Thies, Judy
item Fery, Richard

Submitted to: Nematologica
Publication Type: Abstract Only
Publication Acceptance Date: August 6, 1998
Publication Date: N/A

Technical Abstract: The southern root-knot nematode (Meloidogyne incognita) causes severe yield losses in bell pepper (Capsicum annuum) in the U.S.A. and world-wide. Soil fumigation with methyl bromide is the principal control method currently used in the U.S., but the anticipated ban on methyl bromide use in the U.S. on 1 January 2001 has focused considerable interest on host plant resistance. The first root-knot nematode resistant bell pepper cultivars Charleston Belle and Carolina Wonder were recently developed and released by USDA, ARS, Charleston, S.C. Both cultivars are homozygous for the N gene in pepper that confers resistance in C. annuum to M. incognita. Resistance to M. incognita conditioned by the Mi gene in tomato is ineffective at 28 deg C; however, effectiveness of the N gene at high temperatures is unknown. Responses of the resistant Charleston Belle and Carolina Wonder and their respective susceptible backcross parents, Keystone Resistant Giant and Yolo Wonder B to M. incognita were compared at 24, 28, and 32 deg C. Nematode reproduction and root galling increased (P<0.05) for all cultivars as temperature increased. Both resistant cultivars exhibited a partial loss of resistance at 28 and 32 deg C. At 32 deg C, however, nematode reproduction on resistant cultivars was only 20% of that of susceptible cultivars, root gall indices were still within the moderately resistant range, and shoot dry weights were not reduced. Although a partial loss of resistance occurred in Charleston Belle and Carolina Wonder at high temperatures, resistant pepper cultivars should be a useful component of cropping systems designed to manage M. incognita.

Last Modified: 4/22/2015