Tropical maize (Zea mays L.) germplasm has had limited use in temperate areas because of photoperiod sensitivity. Antigua germplasm from the island Antigua was introduced co Iowa because of its resistance to important pests of maize and its heterosis exposed m crosses with ocher tropical varieties. Mass selection procedures were used to adapt the Antigua Composite germplasm co Iowa conditions. After. Six cycles of mass selection for earlier silk emergence, the selected Antigua Composite flowered 17 days earlier than the original composite. Grain yield and ocher agronomic traits of the adapted scram of Antigua were similar co chose of adapted varieties