Because segregation was still so commonplace in Oxford, MS, cast members Juano Hernandez and Elzie Emanuel were not allowed to stay in the same hotel as their white co-stars; they were boarded in a private home instead.
The film is generally considered as breaking new ground in its depiction of blacks on screen. In 1949 it was certainly highly progressive in the way it portrayed African-Americans.
William Faulkner won the 1949 Nobel Prize for literature in 1950, two years after the novel was published and one year after the film was released. (The Nobel committee had declined to make an award in 1949 and gave it to Faulkner retroactively.)
Not much of a film-goer, William Faulkner did go to see this adaptation of his novel and was much impressed by it.