In 'Dune', what is the name of the Bene Gesserit homeworld?

In 'Dune', the Bene Gesserit homeworld is Wallach IX. The planet is the location of the Sisterhood’s Mother School, where Bene Gesserit members receive their demanding physical, mental, and political training.

The Bene Gesserit are not simply a religious order. They are an influential sisterhood that has shaped imperial politics, arranged marriages, and carefully managed bloodlines for thousands of years. Their long-running breeding program seeks to produce the Kwisatz Haderach, a figure they believe can access forms of awareness unavailable to Bene Gesserit women.

Wallach IX is sometimes confused with Arrakis because the Bene Gesserit are deeply involved in the struggle over spice, and with Chapterhouse because the Sisterhood later establishes a hidden homeworld by that name in Heretics of Dune. In the setting of the original Dune story, however, Wallach IX is the accepted answer. Its school also trains Truthsayers, whose conditioning allows them to detect falsehood and advise powerful rulers.