Strain-specific and recessive QTLs involved in the control of partial resistance to Fusarium oxysporum f. sp. melonis race 1.2 in a recombinant inbred line population of melon.
Fusarium oxysporum f. sp. melonis (FOM) causes serious economic losses in melon (Cucumis melo L.). Two dominant resistance genes have been identified, Fom-1 and Fom-2, which provide resistance to races 0 and 2 and races 0 and 1, respectively, however FOM race 1.2 overcomes these resistance genes. A partial resistance to FOM race 1.2 that has been found in some Far East accessions is under polygenic control. A genetic map of melon was constructed to tag FOM race 1.2 resistance with DNA markers on a recombinant inbred line population derived from a cross between resistant (Isabelle) and susceptible (cv. Védrantais) lines. Artificial root inoculations on plantlets of this population using two strains, one that causes wilting (FOM 1.2w) and one that causes yellowing (FOM 1.2y), resulted in phenotypic and genotypic data that enabled the identification of nine quantitative trait loci (QTLs). These QTLs were detected on five linkage groups by composite interval mapping and explained between 41.9% and 66.4% of the total variation. Four digenic epistatic interactions involving seven loci were detected and increased the total phenotypic variation that was explained. Co-localizations between QTLs and resistance gene homologs or resistance genes, such as Fom-2 and Vat, were observed. A strain-specific QTL was detected, and some QTLs appeared to be recessive.
Perchepied
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Institut National de la Recherche Agronomique, Unité de Génétique et d'Amélioration des Fruits et Légumes, BP 94, 84143 Montfavet Cedex, France.
Dogimont
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Pitrat
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D002874:Chromosome Mapping; D003433:Crosses, Genetic; D028463:Cucumis melo / Q000235:genetics*; D017931:DNA Primers; D004843:Epistasis, Genetic; D005670:Fusarium; D007113:Immunity, Innate / Q000235:genetics*; D021141:Nucleic Acid Amplification Techniques; D010641:Phenotype; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology*; D012150:Polymorphism, Restriction Fragment Length; D040641:Quantitative Trait Loci
D017931:DNA Primers