Identification of genetic loci influencing fruit and leaf traits in tomato plants

The tomato plant (Solanum lycopersicum L.) is a crucial global crop that requires ongoing enhancement through breeding programs to boost yield and fruit quality. In this study, an F2 tomato population of 127 plants, derived from a cross between line TL01860 and line L00548, was grown to identify quantitative trait loci (QTL) associated with ten traits related to fruit and leaf characteristics: fruit fresh weight (FW), fruit firmness (FF), fruit height (FH), fruit diameter (FD), fruit height-diameter ratio (FHDR), fruit red color (FRC), fruit core diameter (FCD), fruit pericarp thickness (FPT), leaf chlorophyll content (LCC), and leaf width (LW). A tomato genetic map was constructed using amplified fragment length polymorphism (AFLP) markers and DArTseq-based single nucleotide polymorphism (SNP) markers. Twenty-six QTL were identified for these traits and mapped to tomato chromosomes using the inclusive composite interval mapping (ICIM) method. The QTL explained the highest accumulative phenotypic variance (APVE) for FW (40.8%), followed by FH (29.5%), FD and LCC (26% each), with the lowest APVE observed for FPT (8.7%). These QTL, identified through AFLP and SNP-based mapping, provide a foundation for fine mapping and candidate-gene cloning, potentially aiding in marker-assisted selection to develop new tomato varieties.