Abstract

ASCENCIO-ALVAREZ, Ada et al. Vascular wilt of tomato: II. Inheritance of resistance to race 3 of Fusarium oxysporum f. sp. lycopersici (Sacc.) Snyder and Hansen in three species of the genus Lycopersicon. Rev. mex. fitopatol [online]. 2008, vol.26, n.2, pp.180-183. ISSN 2007-8080.

Tomate (Lycopersicon esculentum) production in the states of Sinaloa, San Luis Potosi, and Nayarit, Mexico, es at risk because of wilt disease caused by Fusarium oxysporum f. sp. lycopersici, particularly race Fol-3. There are few resistant cultivars despite that this control method is the most economic, effective, and innocuous to manage the disease. Identification of sources of resistance in wild germplasm has gained importance; therefore, the objective of this work was to determine the inheritance of resistance to race Fol-3 in three tomato species: Lycopersicon esculentum, L. peruvianum, and L. pimpinellifolium in the greenhouse. Three hundred F₂ tomato plants, 15-25 days old, from each cross were inoculated by root immersion in a 10^-7 mL L^-1 conidial suspensión of Fol-3; evaluation was carried out 30 days after planting, plants were classified as resistant or susceptible. The G test was used since its goodness of fit allowed to determine if the observed frequencies adjusted or not to the expected ratios. The inheritance of resistance in the six genotypes evaluated was mendelian, with a ratio of three resistant plants with complete dominance to one susceptible.

Keywords : Qualitative characteristics; mendelian inheritance; G test; Lycopersicon esculentum; L. peruvianum; L. pimpinellifolium.

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