Mapping of quantitative trait loci linked to Phytophthora nicotianae var. parasitica resistance in tomato (Solanum lycopersicum L.)

Abstract Buckeye rot is the most devastating disease of tomato. As no work has been done to tag genes responsible for resistance to this disease, present study was planned out to generate segregating population by crossing susceptible parent ‘Solan Lalima’ and resistant parent ‘EC-251649’, followed by phenotypic and genotypic screening of 100 F2 segregants and finally identification of Quantitative Trait Loci (QTL). On phenotyping F2 segregants were scaled in three main categories, five plants as resistant, 43 as susceptible and 52 as highly susceptible. Out of total 153 primers used, 93 primers were found polymorphic with parents which were used for genotyping studies of F2 population. MAPMAKER/EXP version 3.0b resulted in construction of 12 linkage groups with coverage of total genetic map distance of 4660.7 cM. Linkage group 2 was the largest group spanning a distance of 4584.9 cM. QTL Cartographer detected total 22 QTL with placement of 20 QTL on chromosome 2 and single QTL each on chromosome 6 and 7. Identified markers can further be used for marker assisted selection and other molecular studies.