Plants are early with short semiprostrate early growth.
The short, narrow, upright leaves have glabrous leaf sheaths and white auricles. Callao is high yielding and has exceptionally high test weight. Head emergence of Callao is very early and similar to Barsoy. Callao has very high yield potential and exceptional grain quality, which can best be obtained when this cultivar is properly managed, including the use of a growth regulator. Based on limited data, Callao appears to have moderate to good winter hardiness, being similar to Nomini in this respect.