Farmers and scientists have manipulated crops for thousands of years. Gene-editing is what proponents call a more precise version of mutation breeding that’s been used since the mid-1900s. Commercial varieties of edibles, including wheat, barley, rice and grapefruit, were created by mutating DNA with chemicals or radiation. Crops are on the forefront of gene-editing because plant DNA is the easiest to manipulate. San Diego-based Cibus changed one letter from canola’s DNA to create the new variant. Farmers in North Dakota and Montana planted about 20,000 acres of sulfonylurea-resistant canola this year, and Cargill Inc. is making it into cooking oil. Developing a new trait takes just five years with gene-editing, compared with seven to nine years with traditional breeding techniques and as long as 15 years with transgenic methods, which have been used to create the current generation of GMOs.