Hybrid corn beyond heterosis: reading George Shull's hybrid corn articles (1908-1909)

The theoretical conclusion of Shull's first article 'The composition of a field of maize'-the breeder's task is 'the development and maintenance of that hybrid combinationwhich possesses the greatest vigor'-has, for all practical matters, nothing to do with his breeding proposal to make 'as many self-fertilization as practicable... Then all possible crosses are to be made among these different pure strains', namely extending the small grain isolation method to maize. This conclusion should have been clear for an unprejudiced biologist as soon as Shull's second article (January 1909), and was inevitable after his third one (December 1909). This article highlights Shull's skillful rhetoric and semantic that shaped the prejudice blinding biologists for more than a century and their neglect of Shull's stated goals of crop uniformity and breeders' property rights.