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QTLs for Tomato Powdery Mildew Resistance (Oidium lycopersici) in Lycopersicon parviflorum G1.1601 Co-localize with Two Qualitative Powdery Mildew Resistance Genes

February 2003 , Volume 16 , Number  2
Pages  169 - 176

Yuling Bai , 1 Cai-Cheng Huang , 2 Ron van der Hulst , 1 Fien Meijer-Dekens , 1 Guusje Bonnema , 1 and Pim Lindhout 1

1Laboratory of Plant Breeding, Graduate school for Experimental Plant Sciences, Wageningen University, Binnenhaven 5, 6709 PD Wageningen, The Netherlands; 2Syngenta Seeds BV, Postbus 26, 1600 AA Enkhuizen, The Netherlands

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Accepted 22 October 2002.

Tomato (Lycopersicon esculentum) is susceptible to the powdery mildew Oidium lycopersici, but several wild relatives such as Lycopersicon parviflorum G1.1601 are completely resistant. An F2 population from a cross of Lycopersicon esculentum cv. Moneymaker × Lycopersicon parviflorum G1.1601 was used to map the O. lycopersici resistance by using amplified fragment length polymorphism markers. The resistance was controlled by three quantitative trait loci (QTLs). Ol-qtl1 is on chromosome 6 in the same region as the Ol-1 locus, which is involved in a hypersensitive resistance response to O. lycopersici. Ol-qtl2 and Ol-qtl3 are located on chromosome 12, separated by 25 cM, in the vicinity of the Lv locus conferring resistance to another powdery mildew species, Leveillula taurica. The three QTLs, jointly explaining 68% of the phenotypic variation, were confirmed by testing F3 progenies. A set of polymerase chain reaction-based cleaved amplified polymorphic sequence and sequence characterized amplified region markers was generated for efficient monitoring of the target QTL genomic regions in marker assisted selection. The possible relationship between genes underlying major and partial resistance for tomato powdery mildew is discussed.

The American Phytopathological Society, 2003