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QTL Mapping Identifies Novel Source of Resistance to Fusarium Wilt Race 1 in Citrullus amarus
- Branham, Sandra E., Levi, Amnon, Wechter, W. Patrick
- Plant disease 2019 v.103 no.5 pp. 984-989
- Citrullus lanatus var. citroides, Fusarium oxysporum, Fusarium wilt, chromosome mapping, chromosomes, cultivars, inbred lines, parents, plant pathogens, quantitative trait loci, soil fungi, watermelons, United States
- Fusarium wilt race 1, caused by the soilborne fungus Fusarium oxysporum Schlechtend.: Fr. f. sp. niveum (E.F. Sm.) W.C. Snyder & H.N. Hans (Fon), is a major disease of watermelon (Citrullus lanatus) in the United States and throughout the world. Although Fusarium wilt race 1 resistance has been incorporated into several watermelon cultivars, identification of additional genetic sources of resistance is crucial if a durable and sustainable level of resistance is to be continued over the years. We conducted a genetic mapping study to identify quantitative trait loci (QTLs) associated with resistance to Fon race 1 in segregating populations (F₂:₃ and recombinant inbred lines) of Citrullus amarus (citron melon) derived from the Fon race 1 resistant and susceptible parents USVL246-FR2 and USVL114, respectively. A major QTL (qFon1-9) associated with resistance to Fon race 1 was identified on chromosome 9 of USVL246-FR2. This discovery provides a novel genetic source of resistance to Fusarium wilt race 1 in watermelon and, thus, an additional host-resistance option for watermelon breeders to further the effort to mitigate this serious phytopathogen.