Thirty-five plants ofAgropyron trachycaulumfrom northern Canada were categorized as to the latitude of origin. Categories were 53–55, 55–58, 58–61, and 61–68° north latitude. In field plots at Beaverlodge (latitude 55° N) the plants originating from farthest north had the shortest number of days from heading to maturity and lowest average height and seed yield. Controlled environment studies confirmed that plants from north of 60° latitude have reduced capability of producing seed culms in summer environments with less than continuous light. Seed production of such species would be suspect in the current farming areas at lower latitudes. If large quantities of seed were required, new seed production areas may have to be developed in northern latitudes.