 The 1937 federal work objectives included goals of improving resistance to disease and improving tolerance of long and short days as well as high and low temperatures.By the 1950s many American varieties were being used in Great Britain such as the Fragaria ves a x Fragaria chiloensis In the mid 50s, varieties were released that were resistant to red stele root disease.Unlike Great Britain and the United States, France allowed strawberry breeding to remain a largely private study for the early 20th century.