Three QTLs from Lycopersicon peruvianum confer a high level of resistance to Clavibacter michiganensis ssp michiganensis

Lycopersicon peruvianum LA2157 originates from 1650 m above sea level and h arbours several beneficial traits for cultivated tomatoes such as cold tole rance, nematode resistance and resistance to bacterial canker (Clavibacter michiganensis ssp. michiganensis). In order to identify quantitative trait loci (QTLs) for bacterial canker resistance, a QTL mapping approach was car ried out in an F-2 population derived fr om the interspecific F-1 between L ycopersicon esculentum cv Solentos and L. peruvianum LA2157. Three QTLs for resistance I-napped to chromosomes 5, 7 and 9 respectively. The resistance loci were additive and co-dominant with the QTL on chromosome 7 explaining the largest Dart of the variation for resistance in the F-2 population. Th e combination of this QTL with either of the other two QTLs conferred a res istance similar to the level in the resistant parent L. peruvianum. Some RF LP markers flanking this QTL on chromosome 7 were converted into SCAR marke rs allowing efficient marker-assisted selection of plants with high resista nce to bacterial canker.