Abstract: The fruit weight of F1 generation derived from the cross between cherry tomato‘VFNT Cherry’（syn. LA1221）and processed tomato‘Heinz1706’was over parents，showing obvious heterosis. In order to analyze the genetic basis of this phenomenon，using F2 population obtained from the above F1generation self-crossing，the QTL mapping of tomato fruit weight was carried out by QTL-seq and single marker analysis. A total of ten fruit weight QTLs were identified，and eight of which were dominant. Among the eight dominant QTLs，five QTLs were incomplete dominant[QTL for Fruit Weight 2.1（qFW2.1），qFW5.2，qFW7.1，qFW8.1，qFW9.1]，and three QTLs were over-dominant[qFW1.1，qFW5.1，qFW6.1]. Moreover，the big fruit alleles of qFW2.1，qFW5.1，qFW7.1，qFW8.1，and qFW9.1 were from‘Heinz1706’，and the big fruit alleles of qFW1.1，qFW5.2，qFW6.1 were from‘VFNT Cherry’. Therefore，the heterosis of tomato fruit weight in the above F1 generation may be due to its aggregation of dominant large fruit alleles from both parents. Among the eight dominant QTLs，qFW9.1 had the highest contribution rate of phenotypic variation，reaching 12.19%. The qFW9.1 locus was further validated and narrowed to a 4.5 megabase pair by recombinant progeny testing

Key words: tomato, fruit weight, QTL-seq, single marker analysis