Inheritance Analysis and Identification of SSR Markers Linked to Late Blight Resistant Gene in Tomato

Late blight caused by Phytophthora infestans is the most serious disease of tomato production in China. Studies on thegenetics of resistance and identification of molecular markers are very useful for breeding late blight resistant varieties.The objective of this paper was to study the inheritance of late blight resistance and identify simple sequence repeat (SSR)markers associated with resistance allele in tomato (Lycopersicon esculentum Mill). The results came from an F2 progenyof 241 plants derived from a cross between 5# inbred line that is susceptible to late blight and a resistant accessionCLN2037E. The late blight responses of F2 plants were tested by artificially inoculation of detached-leaflets in plate andnatural infection assayed under greenhouse conditions. Both methods showed that the resistance is dominant andinherited as monogenic trait. Genetic mapping and linkage analysis showed that the late blight resistance gene Ph-ROLwas located on chromosome 9 with a genetic distance of 5.7 cM to the SSR marker TOM236.