VIEW ARTICLE

Genetics

Inheritance and Nature of Resistance in Beans to Fusarium oxysporum f. sp. phaseoli. Raul de L. D. Ribeiro, Research assistant, Department of Plant Pathology, University of Wisconsin, Madison 53706; D. J. Hagedorn, professor, Department of Plant Pathology, University of Wisconsin, Madison 53706. Phytopathology 69:859-861. Accepted for publication 4 March 1979. Copyright 1979 The American Phytopathological Society. DOI: 10.1094/Phyto-69-859.

Strains of Fusarium oxysporum f. sp. phaseoli, representing two distinct pathogenic races, were used to study the mode of inheritance and the nature of yellows resistance in beans. Analysis of progenies of each of the crosses between four resistant cultivars and a susceptible cultivar indicated that a single gene controls resistance to each race. Resistance to a race from Brazil appears to be controlled by a dominant gene tentatively designated as Fop 1. This gene is present in the cultivars Tenderette, Pintado, and possibly Early Gallatin. Resistance to a race from the United States appears to be controlled by an incompletely dominant gene tentatively designated as Fop 2. The heterozygous F₁ progeny of the cross of resistance (Preto Uberabinha) and susceptible cultivars displayed a degree of resistance to the U.S. race lower than that of the resistant parent. Resistance to both races of the fungus is expressed by a restriction of distribution and/or growth of the pathogen in the vascular system of inoculated plants.