This paper explores the nature of scientific research and innovation at the intersection of technological systems via a study of atomic age plant breeding. I show how the well-established framework of “large technological systems” can be deployed to understand research dynamics in the Cold War life sciences, and further suggest that this framework might be useful in understanding still other areas of scientific research. I argue that the development of experimental tools and research programs dedicated to plant breeding via nuclear-derived technologies arose where researchers experienced the imperatives of innovation within two technological systems—nuclear and agricultural—simultaneously. In the absence of a significant infrastructure for nuclear agriculture, it was the mobility of innovations, the exchange of research tools and practices across experimental settings and research domains, which enabled nuclear-aided plant breeding to flourish for a time. As I show, understanding the dynamics of the technological systems in which researchers were embedded, including their interactions with other systems, is essential to understanding this unlikely area of research inquiry, the novel tools it relied upon, and the unusual scientific careers to which it gave rise.