Article ID: 26024
Fusarium crown and root rot (FCRR), caused by Fusarium oxysporum f. sp. radicis-lycopersici, is a devastating soil-borne disease affecting tomatoes. Resistance is conferred by a single dominant locus, Frl, introgressed from Solanum peruvianum. Despite the development of DNA markers linked to Frl, some resistant cultivars exhibit genotypes that are susceptible to existing markers, thus limiting their utility in breeding programs.
We performed QTL-seq analysis using an F2 population derived from the commercial cultivar ‘Super First’ and identified a candidate region on chromosome 9. Using marker genotyping of the F2 population, we delimited the Frl locus to a region upstream of 4.97 Mb. Comparison of genome sequences between resistant lines revealed an 80-kb core region (4.87–4.95 Mb) with near-complete sequence identity, suggesting a shared introgression fragment. We developed a DNA marker, MT111112, within this region, which showed tight linkage to FCRR resistance in the F2 population. Furthermore, MT111112 correctly identified resistant cultivars (‘Aitaki 1’, ‘Renaissance’ and ‘TY First’) that were misclassified by existing markers, demonstrating higher identification accuracy and broad applicability across diverse genetic backgrounds. This marker enables a more reliable marker-assisted selection for the development of FCRR-resistant tomato cultivars.
