Genetic engineering involves the introduction of a specific gene into the genome of a plant to obtain a desired trait. The gene introduced may come from another plant species or from any other organism. While traditional plant breeding involves crossing related plants, genetic engineering uses modern biotechnology tools that allow breeders to be more precise and enables the introduction of useful traits that are otherwise difficult or impossible to achieve by conventional means. The goals of genetic engineering are the same as with traditional breeding. Scientists may aim to improve crop performance in the field by conferring pest and disease resistance, herbicide resistance, or tolerance to environmental stresses (such as salinity and drought or flooding). They may also aim to develop products with enhanced value, such as improved post-harvest life, nutritional value, or other health benefits.