The rate of crop improvement must increase to meet rising global demand for food. Crop breeding pipelines can be hampered by the imprecision and multi-generational timeframe of methods such as intercrossing and stochastic mutagenesis used to generate variation. Genome editing can generate targeted allelic series of trait-related genes and regulatory elements, creating a series of variable phenotypes for breeding within a single generation. Disrupting genic and regulatory regions is particularly effective for engineering quantitative traits. Although qualitative traits can be more difficult to engineer using disruption, precise base editing may allow an efficient path to rationally improve qualitative traits if protein function can be accurately modelled. As functional understanding of genes and regulatory elements increases, genome editing can enhance the predictability of plant breeding outcomes and will ensure food security.