There is no pre-screening requirement for Tuba.
The Graduate audition repertoire in tuba is patterned after a typical undergraduate senior recital. In order to provide some latitude, the requirements are not dictated. However, you must prepare sufficient material to perform a full solo recital containing works which show a diversity of periods and styles.
AD applicants must prepare a program of no less than 70 minutes duration, representing at least three style periods and including at least two large-scale works.