A comparative examination of the two major exporters' dynamic wheat acreage response models reveals that U.S. farmers have responded more .sensitively than their Canadian counterparts to government programs but less sensitively to price. This results from differences in the method of government intervention and possibilities for crop substitution. Direct control on acreage characterizes the U.S. approach,. while the Canadian approach is one_ of guaranteeing minimum returns and volumes marketed through the Canadian Wheat Board. In addition, more alternative crops are available for substitution in Canada than in the U.S.