QTL Mapping Identifies Novel Source of Resistance to Fusarium Wilt Race 1 in .

Fusarium wilt race 1, caused by the soilborne fungus Schlechtend.: Fr. f. sp. (E.F. Sm.) W.C. Snyder & H.N. Hans (), is a major disease of watermelon () 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 race 1 in segregating populations (F and recombinant inbred lines) of (citron melon) derived from the race 1 resistant and susceptible parents USVL246-FR2 and USVL114, respectively. A major QTL () associated with resistance to 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.