- Thomas S. Buchanan, Constantin Constantinovich Nikiforoff, Dwight McBryde Simpson, Dwight Moore DeLong, Frank M. Eaton, G. J. Haeussler, G. R. Free, George Wright Hoffman, Gustav A. Wiebe, Harold Andrus Jaynes, Harry Ardell Allard, Henry Hopp, J. I. Lauritzen, James Robert Dawson, Joseph Stuart Caldwell, Kenneth Thurman Williams, Lawrence Zeleny, Loyd L. Stitt, Marshall Weddell Stone, Raymond Peter Christensen, Robert Merton Walsh, Ruth Elmquist Rogers, Theodore Roosevelt Gardner, Thomas Charles Chadwick, Wilbur Tibbils Pentzer, Caroline L. Adams, Charles A. Fort, David Victor Kopland, E. K. Bynum, George Henry Englerth, Helen Garrison Wheeler, James Stewart Wiant, Lawrence Bemis Parker, Morris Harvey Neustadt, Philip Russell Cowan, R. R. Whetstone, Ronald Lester Mighell, Roy Drummond McCallum, Samuel Palkin, Wightman Wells Garner, G. M. Stone, Harry Humfeld, John Henry MacGillivray, Lucille Reinbach-Welch, Miles Stratford Mayhugh, R. R. Graves, R. T. Balch
· 1941
- A. D. McNair, Curtis Paul Clausen, Dalton Giles Miller, Dan Hansen, Dean Humboldt Rose, Duncan Dunning, Edward Florince McCarthy, Erasmus Manford Nighbert, Erval Jackson Newcomer, Eubanks Carsner, Frederick Vernon Rand, Harold Andrus Jaynes, James Robert Dawson, L. P. Rockwood, Ned Royce Ellis, Oris Vernon Wells, Paul Oman, Perez Simmons, Philip Lindsey Gile, R. D. Garver, Stephen Harold Hastings, William Albert Hartman, Arthur Edgerton Seamans, Edward Gantt Noble, George Wilburn Ellington, J. W. Connelly, Jacob Martin Lutz, Lester Henry Reineke, Lillian Claire Cash, Max Moore Reeher, Philip W. Manson, R. R. Graves, Raymond Herbert Miller, Roland McKee, Roscoe Harrison Carter, Archie Glenn Van Horn, David Victor Kopland, Theodore Roosevelt Gardner
· 1933
- Carlos G. Bates, William Buckhout Greeley, Alfred R. Lee, Benjamin Yoe Morrison, Charles Wesley Hauck, D. F. Fisher, Edwin LeFevre, George McMillan Darrow, Harvey W. Hawthorne, Hubert Bunyea, J. M. Westgate, James Herbert Beattie, James Robert Dawson, John Oscar Williams, Leland Ossian Howard, Morley Allan Jull, Neale F. Howard, Paul Albert Ewing, Samuel Hawkens Ray, William Daniel Smith, William Henry Black, Henry James Franklin, Charles Brooks, Earl Beach Krantz, Earl W. McComas, Lynn Shelby Robertson, O. G. Malde
· 1928
- Alfred Leroy Baker, Benton Mehrling Stahl, Charles William Loomer, Claude Kedzie Shedd, Donald Eisenbrey Church, Edward Pendleton Carter, Elsa Orent-Keiles, Fenner Satterthwaite Stickney, Frank Custer Edminster, Harry Curtis Young, Hazel Marie Fletcher, Herbert Halden Walkden, James Robert Dawson, Joseph Bailey Edmond, Leo E. Holman, M. A. Yothers, Marshall Tracy Deonier, Matthew Drosdoff, Myron Francis Babb, Ralph Dickieson Jennings, Ralph Leroy Parshall, Robert Douglass McCulley, Roy Wesley Nixon, Tom Part Cassidy, W. P. Baird, United States. Department of Agriculture, Arnold M. Hansen, David Victor Kopland, Dwight Fletcher Barnes, Frank Waldemar Carlson, George Yankush Young, James E. Kraus, Maurice E. Dahmus, Vernon Webster Johnson, Walter S. Atkinson, William Henry Black, Arthur Clifton McIntyre, Mary Ellen Duensing, Perez Simmons, Roy Magruder
· 1950
- Arthur Henry Senner, Auton William Skuderna, Benjamin Ralph Stauber, Charles Brooks, Clarence Elbert Clement, Curtis Paul Clausen, Edmund Lambert, Edward E. Clayton, Erval Jackson Newcomer, George McMillan Darrow, Glenn Arthur Cumings, Glenn Marsh Smith, James Herbert Beattie, James Robert Dawson, James Warren Hubbard, L. H. Patch, M. McPhail, Marion Bertice McKay, Ralph Edwin Beckett, Rosemary Laughlin Marsh, Rosemary Loughlin, Theodore Bergen Manny, Victor Rickman Boswell, William Doyle Reed, United States. Department of Agriculture, Archie Glenn Van Horn, Charles Evans Cormany, Chester Ihner Bliss, Erskine McFarlane Livingstone, Eugene Taylor Batten, Frederick Wulling Herbert, George Fordyce Waldo, John Gordon Gaines, Austin W. Morrill (Jr.), Lewis Alexander Hurst
· 1932