The genetic analysis of resistance to fusarium crown and root rot of tomato

The tomato line IRB-301-31, resistant to fusarium crown and root rot ( Fusarium oxysporum f.sp. radicis-lycopersici ) was crossed with two susceptible cultivars, Motelle and Earlypak No. 7. When F₁, F₂ and backcross progenies were inoculated at the one-leaf stage with a suspension of spores of the pathogen, all could be classified as either resistant (healthy) or susceptible (dead). The ratios of resistant to susceptible plants indicated that resistance was conferred by a single dominant gene, designated Fr1.