We begin a systematic investigation of derived categories of smooth projective toric
varieties defined over an arbitrary base field. We show that, in many cases, toric
varieties admit full exceptional collections, making it possible to give concrete
descriptions of their derived categories. Examples include all toric surfaces, all toric
Fano 3-folds, some toric Fano 4-folds, the generalized del Pezzo varieties of
Voskresenskiĭ and Klyachko, and toric varieties associated to Weyl fans of type
.
Our main technical tool is a completely general Galois descent result for
exceptional collections of objects on (possibly nontoric) varieties over nonclosed
fields.