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Caldwell, Ralph M. (Ralph Merrill), 1903-



  • Existence: June 27, 1903 - November 2, 1976

Biographical Information

Ralph Merrill Caldwell was born June 27, 1903, in Brookings, South Dakota. He graduated from what is now South Dakota State University with a Bachelor of Science (B.S.) degree in Agronomy in 1925. He earned a Master of Science (M.S.) degree in Botany in 1927 and the PhD in Plant Pathology in 1929, both from the University of Wisconsin. He was married to Margaret Dunlap and they were the parents of one daughter, Janet (Mrs. R. W. Storts).

Caldwell served a two-year stint as Wisconsin State Leader for Barberry Eradication (1928-1930). In 1930 he came to Purdue University as an Associate Plant Pathologist in the U.S. Department of Agriculture (now the Agricultural Research Service) in charge of wheat leaf rust research.

Dr. Caldwell resigned his position with the USDA in 1937 to become Head of the Department of Botany and Plant Pathology at Purdue University (1937-1950), a position he held for 17 years, while remaining a USDA Collaborator. In 1954, Caldwell returned to full-time research and cereal breeding. On several occasions, Dr. Caldwell served as consultant to the international wheat breeding program of CIMMYT, working in Mexico with scientists and graduate students from throughout the world. Following his retirement on June 20, 1971, Caldwell served as wheat breeding consultant to the DeKalb Seed Company.

During his career, Dr. Caldwell authored over 40 journal articles and numerous reseach bulletins. He was a member, fellow, and held leadership positions in the following professional societies: American Phytopathological Society, American Society of Agronomy, Crop Science Society of America, American Association for the Advancement of Science, and Indiana Academy of Science. He received the Crops and Soils Merit Award of the Indiana Crop Improvement Association in 1954 and the Purdue Agricultural Alumni Association's "Certificate of Distinction" in 1965.

Caldwell died November 2, 1976, in College Station, Texas.


"Caldwell, Ralph M. (Ralph Merrill), 1903-." Library of Congress Name Authority File. />

Schafer, John F. "Pioneer Leaders in Plant Pathology: Ralph M. Caldwell." Annual Reviews of Phytopathology. Vol. 31. (1993): 32-41. />

Athow, Kirk L., Ralph J. Green, Jr., John F. Schafer, and Gregory Shaner. "Ralph Merrill Caldwell, 1903-1976." Phytopathology. Vol. 67, No. 11 (1977): 1317. />

Found in 1 Collection or Record:

Ralph M. Caldwell papers

 Collection — Box: Communal Collections 17, Placement: 25
Identifier: MSF 80
Scope and Contents This collection consists of one folder containing three articles written by Ralph Caldwell.
Dates: 1934 - 1943