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-carotene concentration, 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, NC84173, and an inbred accession, LA722 (Lycopersicon pimpinellifolium).The two parental lines and the 116 RILs were planted in an alpha-lattice design with two replications. At the end of the growing season, 30-50 representative ripened fruits were harvested randomly from each RIL and the parents to record the traits. A linkage map was constructed using 121RFLP and 67RGA markers arranged in 12 groups. Transgressive segregation was observed for all the traits. A total of 10 quantitative trait loci (QTLs) were detected for the six traits using composite interval mapping. Co-localization 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.