Abstract：Cucurbita ficifolia genome contains a large number of beneficial genes of great agronomic value, which confers multiple traits including strong stress tolerance for low temperature, drought, poor soil and fusarium wilt of Cucurbits. However, it is difficult to transform these beneficial genes into other cultivated cucurbit crops by the conventional breeding program, while the transformation by TAC vector library may serve as an alternative. To facilitate the mapping and cloning of these beneficial genes, a genomic transformation-competent artificial chromosome (TAC) library of Cucurbita ficifolia was constructed by using the vector of pYLTAC747NH/sacB in this study．The library consisted of 57 560 individual clones, which was stored in one hundred fifty 384-well plates with an average DNA inserted size of 45 kb ranging from 20~100 kb(more than 40% of the clones were above 40 kb); and the whole library covers 7× genome equivalents. All 15 selected clones carried inserted fragments, and the restriction digestion of the plasmids also indicated that TAC clone could be stably replicated and retained in Escherichia coli DH10B after sub-culturing 30, 60 and 100 generations， thus demonstrating that high quality TAC library was created. To conclude, our study suggest that TAC library can provide valuable information for the isolation of genomic clones containing stress tolerance genes, functional validation, the construction of a physical map and the genome sequencing.
