Beautiful and delicious mutants: The origins, fates, and benefits of molecular sequence variation in plant evolution and breeding.

Heritable sequence changes conferred by mutations have historically been, and continue to be, a valuable source of genetic variation in plant breeding to deliver vegetables, fruits, flowers, and grains with improved quality, diversity, and performance. Genetic diversity in domesticated crops is not entirely preexisting or fixed. This diversity depends on the progression of breeding tools and methodologies that deliver mutations to the enterprise of plant improvement. While breeding has been part of human history for thousands of years, DNA was not recognized as the molecular basis of inheritance until the 1940s. Even more recently, sequencing technologies have allowed us to reveal the allelic variation responsible for naturally occurring phenotypic characteristics that were advanced by evolution and selective breeding. Here, we summarize specific examples of sequence variation that illustrate the extent and impact of plant mutation for agriculture and the essential value of mutational tools to generate additional useful genetic variation. Over time, these tools have been successfully deployed in plant breeding and have been accepted as a means to produce beneficial variation in crops without compromising safety. We then describe the potential utility of genome editing as a versatile technology to introduce beneficial mutations and to enable plant breeding. Compared with other sources of mutation, genome editing satisfies the same safety requirements while also offering technological advancements to improve the performance and quality of crops that our society depends upon.