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Resistance

Genetics of Resistance to Fusarium oxysporum f. sp. melonis Races 0, 1, and 2 in Muskmelon Line MR-1. F. W. Zink, Department of Vegetable Crops, University of California, Davis 95616; C. E. Thomas, USDA, Agricultural Research Service, U.S. Vegetable Laboratory, Charleston, SC 29414. Phytopathology 80:1230-1232. Accepted for publication 29 June 1990. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1990. DOI: 10.1094/Phyto-80-1230.

In artificial inoculation studies, muskmelon (Cucumis melo) breeding line MR-1 was resistant to races 0, 1, and 2; but not 1,2y or 1,2w of Fusarium oxysporum f. sp. melonis. Segregation ratios for F₁, F₂, and BC₁ populations of crosses between resistant MR-1 and susceptible Topmark indicated that resistance to races 1 and 2 of Fusarium wilt is conferred by single dominant genes and that resistance to race 0 is also conferred by a single dominant gene. Linkage tests indicated that the genes for resistance to race 1 and race 2 assort independently. Allelism tests showed that the single dominant genes in MR-1 that confer resistance to races 0 and 2 and races 0 and 1 are the same genes or alleles of Fom-1 in differential cultivar Doublon and Fom-2 in differential line CM 17-187, respectively.