Most conventional and mode crop-improvement methods exploit natural or artificially induced genetic variations and require laborious characterization of the progenies of multiple generations derived from time-consuming genetic crosses.Genome-editing systems,in contrast,provide the means to rapidly modify genomes in a precise and predictable way,making it possible to introduce improvements directly into elite varieties.Here,we describe the range of applications available to agricultural researchers using existing genome-editing tools.In addition to providing examples of genome-editing applications in crop breeding,we discuss the technical and social challenges faced by breeders using genome-editing tools for crop improvement.