Affiliation: | 1. Crops Research Division, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 2. Department of Horticulture, North Dakota State University, Fargo, N.D. 3. Department of Horticulture, University of Nebraska, Lincoln, Nebr. 4. Department of Horticulture, University of Minnesota, St. Paul, Minn. 5. Experiment Station La Moline, Lima, Peru 6. Canada Department of Agriculture Research Station, Frederiction, N. B., Canada
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