As a defender of the fundamental importance of Mendel’s experiments for understanding heredity, the English biologist William Bateson did much to publicize the usefulness of Mendelian science for practical breeders. In the course of his campaigning, he not only secured a reputation among breeders as a scientific expert worth listening to but articulated a vision of the ideal relations between pure and applied science in the modern state. Yet historical writing about Bateson has tended to underplay these utilitarian elements of (...) his program, to the extent of portraying him, notably in still-influential work from the 1960s and 1970s, as a type specimen of the scientist who could not care less about application. This paper offers a corrective view of Bateson himself—including the first detailed account of his role as an expert witness in a courtroom dispute over the identity of a commercial pea variety—and an inquiry into the historiographic fate of his efforts in support of Mendelism’s productivity. For all that a Marxian perspective classically brings applied science to the fore, in Bateson’s case, and for a range of reasons, it did the opposite during the Cold War. (shrink)