FRESNO, Calif. — A renowned strawberry researcher in California broke patent law and violated a loyalty pledge to his former university by taking his work with him to profit from it in a private company, a jury in San Francisco decided Wednesday.

Professor Douglas Shaw formed his own research firm with others after retiring from the University of California, Davis, where for years he had overseen the school’s strawberry breeding program.

Jurors in the federal court decided that he used seeds developed at UC Davis without gaining the university’s permission.

The rift struck fear in some farmers in California, the No. 1 strawberry-growing state, that it would stymie research.