Abstract Acrylamide is a carcinogenic contaminant that forms from free (non-protein) asparagine and reducing sugars during high-temperature cooking and processing. Almost all starchy foods are affected, including those produced from grains, tubers, beans and storage roots. Food businesses in the European Union face ever-tightening regulations on acrylamide, and compliance would be greatly facilitated by the development of crop varieties with reduced acrylamide-forming potential. We have used CRISPR/Cas9 to knock out the asparagine synthetase-2 (TaASN2) gene of bread wheat, producing partial and total nulls. One of the lines is also a partial null for the TaASN1 gene. Free asparagine concentrations in the grain of the edited lines were substantially reduced compared with wildtype. Wheat lines with mutations in the TaASN2 gene have also been produced by chemical mutagenesis, and we have also assessed the effect of a natural deletion that means that the B genome TaASN2 gene (TaASN-B2) is missing in some wheat varieties. A field trial of low asparagine genotypes produced using CRISPR/Cas9 and chemical mutagenesis (the first field trial of CRISPR wheat in Europe) has just been harvested. Future field trials may benefit from the relaxation of rules governing GE plant field trials in the UK. The efficiency of the CRISPR/Cas9 system, even when applied to wheat and other crop species, means that it is applicable for a wide range of genetic interventions, including those affecting starch accumulation and composition. However, it is important that any interventions do not affect the free asparagine concentration because of the implications for food safety and regulatory compliance. |