Identification and characterization of quantitative trait loci related to chemical traits in tomato (Lycopersicon esculentum Mill.)

Traits such as soluble solids content, fruit acidity, pH, fruit lycopene concentration, fruit beta-caroteneconcentration, and fruit xanthophyll concentration are very important to the tomato industry. In this study,quantitative trait loci (QTL) analysis of these traits was performed using a recombinant inbred line (RIL)population derived from a cross between a tomato (Lycopersiconesculentum Mill)line, NC۸۴۱۷۳, and an inbred accession, LA۷۲۲ (Lycopersicon pimpinellifolium).The two parental lines and the ۱۱۶ RILs were planted in an alphalattice design with two replications. At the end of the growing season, ۳۰-۵۰ representative ripened fruits were harvested randomly from each RIL and the parents to record the traits. A linkage map was constructed using ۱۲۱RFLP and ۶۷RGA markers arranged in ۱۲ groups. Transgressive segregation was observed for all the traits. A total of ۱۰ quantitative trait loci (QTLs) were detected for the six traits using composite interval mapping. Colocalization of QTLs for lycopene, beta-carotene, and xanthophyll may reflect the pleiotropy effect or genetic linkage between genes via physiological relationships among these traits. This analysis shows that the introgression of wild germplasm may improve the nutritional quality of tomatoes.