Experimental (i.e., unreleased) strains are identified by a number with a state or province code letter prefix. Additional code letters may be used to designate the individuals within a state or province that developed the strain. These codes are a compilation of codes used in the Northern and Southern Uniform Soybean Tests since 1943.
Strains originating from Pioneer Hybrid generally begin with the letter "P" followed by 4 digits ie P2345. Some Pioneer strains have names of the form P followed by two digits followed by one letter followed by two digits ie P49M23.
Below, A.E.S. = Agricultural Experiment Station
| Prefix | Location and Affiliation |
|---|---|
| A | Iowa A.E.S. (A=W. Fehr, AR=S. Cianzio, AX, AP, AD=D.E. Green) |
| Ar | Arizona A.E.S. |
| AS | Alabama A&M Univ. |
| Au | Alabama A.E.S. |
| B | Southwestern Irrigation Field Station, Brawley, CA and US Regional Soybean Lab., Urbana, IL |
| C | Purdue (Indiana) A.R.P. (C=J.R. Wilcox, CL=A. LeRoy, CX, CR=K. Rainey) |
| CM | Canada Dept. of Agriculture, Morden, Manitoba |
| Co | Coker Pedigreed Seed Co., Hartsville, SC |
| D | Mississippi A.E.S. |
| D; DA; DB; DT; DS; DMK; LG | Delta Branch Experiment Station and USDA-ARS at Stoneville, MS |
| DSN | Indiana NAM Strains (K. Rainey, B. Diers, J. Specht) |
| E | Michigan A.E.S. |
| F | Florida A.E.S. |
| FWH | Florida A.E.S. Walnut Hill, FL |
| FC | Forage and Range Research Branch, USDA |
| Ga; G | Georgia A.E.S. Note: A T in a Georgia number indicates selection made at Tiffton |
| H | Ohio A.R.D.C. (HC=R.L. Cooper, HF=R. Fioritto, HS=S.K. St. Martin/L. McHale, HM=L. McHale, HX, HC=R.L. Cooper, HW=A.K. Walker) |
| J | Delta Branch A.E.S., West Tennessee A.E.S and ARS |
| J.E.W. | John Wannamaker, St. Matthews, SC |
| JTN | Tennessee A.E.S., Jackson, TN and USDA-ARS |
| K | Kansas A.E.S. |
| Ky | Kentucky A.E.S. |
| L | Illinois A.E.S. (LD=B. Diers, LG=R.L. Nelson, LN=C.D. Nickell, LS=M. Schmidt, LA LD LU=R.L. Cooper, LN=C.D. Nickell) Note: Second L in a number indicates selection made at Eldorado, IL |
| La | Louisiana A.E.S. |
| LS | Southern Illinois University (LS= L. Schmidt) |
| M; II | Minnesota A.E.S. |
| Md | Maryland A.E.S. |
| Me | Maine A.E.S. |
| N; C; NCC; NTC; NTCPR; TCWN; JWB; NLM | North Carolina A. E. S. and USDA-ARS |
| ND | North Dakota A.E.S. |
| NDPJE | North Carolina A. E. S. and USDA-ARS |
| O, OT, B | Central Experiment Farm, Ottawa, Ontario |
| O, OX | Research Station, Harrow, Ontario |
| OAC | University of Guelph, Guelph, Ontario |
| OK | Oklahoma Agricultural Experiment Station |
| ORC | Ridgetown, Ontario |
| OT | Central Experimental Farm, Ottawa, Ontario |
| OX | Research Station, Harrow, Ontario |
| P | Paymaster Farm, Plainview, TX |
| PI | Plant Inventory |
| R | Arkansas A.E.S. |
| Rebel | Stoneville Pedigreed Seed Co., Stoneville, MS |
| RJ | Arkansas State University, Jonesboro |
| S; LG | Missouri A.E.S. (SS=D.Sleper UM Delta Center, SA=A. Scaboo) |
| SA | Missouri A.E.S. (SS=D.Sleper or UM Delta Center) |
| SC | South Carolina A.E.S. Clemson, SC |
| SD | South Dakota A.E.S. |
| SL | US Regional Soybean Laboratories - Illinois and Missouri |
| TN | Tennessee A.E.S. |
| Ts | Texas A.E.S. |
| TSB | Texas A.E.S, Beaumont, TX |
| T | Soybean Genetic Type Collection, USDA, Urbana, IL |
| UA | Arkansas A.E.S., Univ. of Arkansas |
| U, NEX | Nebraska A.E.S. |
| UD | Delaware A.E.S. |
| UM | University of Manitoba, Winnipeg, Manitoba |
| UT | Tennessee A.E.S. |
| V; B | Virginia A.E.S., Virginia Tech |
| VS | Virginia A.E.S., Virginia State University |
| W | Wisconsin A.E.S. |