Frank Morton has been breeding lettuce since the 1980s. His company offers 114 varieties, among them Outredgeous, which last year became the first plant that NASA astronauts grew and ate in space. For nearly 20 years, Morton’s work was limited only by his imagination and by how many different kinds of lettuce he could get his hands on. But in the early 2000s, he started noticing more and more lettuces were patented, meaning he would not be able to use them for breeding. The patents weren’t just for different types of lettuce, but specific traits such as resistance to a disease, a particular shade of red or green, or curliness of the leaf. Such patents have increased in the years since, and are encroaching on a growing range of crops, from corn to carrots — a trend that has plant breeders, environmentalists and food security experts concerned about the future of the food production.