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Inheritance of Resistance to a Colorado Race of Fusarium oxysporum f. sp. phaseoli in Common Beans. M. O. SALGADO, Former Graduate Student, Colorado State University, Fort Collins 80523. H. F. SCHWARTZ, Professor, Department of Plant Pathology & Weed Science, and M. A. BRICK, Professor, Department of Soil and Crop Sciences, Colorado State University, Fort Collins 80523. Plant Dis. 79:279-281. Accepted for publication 29 November 1994. Copyright 1995 The American Phytopathological Society. DOI: 10.1094/PD-79-0279.

Fusarium wilt of common bean Phaseolus vulgaris caused by Fusarium oxysporum f. sp. phaseoli (FOP) is a serious disease in many production areas of the world. Inheritance of resistance in common bean to a pathogenic race of FOP isolated from pinto bean, U.I. 114, in Colorado was investigated. Resistant (R) and susceptible (S) common bean lines and cultivars from diverse sources were used as parents. The parental material, and F2 and F3 progeny derived from crosses between R and S lines were evaluated for reaction to FOP using a seedling root-clip inoculation technique under controlled greenhouse conditions. Inheritance of resistance to FOP differed among the parental lines and cultivars. Three segregation patterns were observed in the F2 progeny of crosses between R and S parents. In one group, segregation patterns fit a single completely-dominant gene model (3R:1S), whereas segregation in the other group fit a more complex inheritance pattern in which recessive gene action controlled resistance to FOP. Other resistance patterns were more indicative of a quantitative pattern. Resistant lines that possessed single dominant genes for resistance originated from the Durango race, while resistant lines having recessive genetic resistance were from the Mesoamerican race of the Middle American Center of Diversity.