||The International Durum Yield Nursery is one of a series of international yield trials designed to measure the performance ·and adaptation of cereals in a wide variety of latitudes, climates, fertility conditions, water management and disease complexes. The first of these nurseries, the International Spring Wheat Yield Nursery has been conducted for a number of years and continues to provide very valuable information. Results from these spring wheat trials have shown that it is possible to produce varieties of nearly universal adaptation as well as varieties adapted to only a narrow environmental range. Experience gained from the spring wheat yield nurseries has been used as a basis for designing the present durum nurseries. Apart from being a source of fundamental information concerning the adaptation of durum wheat, the International Durum Yield Nursery will serve as a means of testing promising material on a much broader basis than is usually available to an individual breeder. Further, it will allow local research and extension workers to compare the performance of durum wheat from other countries, with the best of their own material. Finally, the nursery will serve as a source of new valuable genetic variability which the cooperator may use directly or in crosses within his breeding program. The results of the International Durum Yield Nursery will be statistically analyzed and published for general distribution. It is important that cooperators study carefully the following, pages which provide the directions for the conduct of the nursery and the note-taking techniques. The value of these nurseries will depend to a large degree on the quality of the data which is returned for analysis. It is understood that any country collaborating in these tests will be free to use any of the material included in the nursery, either as parental material or as commercial varieties. In this latter case, the country of origin of the variety or line under multiplication should be recognized. We sincerely request the cooperation of all persons or institutions interested in this test. It is a collective endeavor and its success depends upon what is collectively contributed to its improvement. We realize that it may have faults and limitations and would appreciate any suggestion for its improvement.