1. Dep. Plant and Soil Sciences; Univ. of Kentucky; Lexington KY 40546
2. EMBRAPA (Empresa Brasileira de Agropecuaria)-Soja; Rodovia Carlos Joao Strass; Caixa Postal 231 Londrina PR Brazil
3. School of Plant, Soil, and Environmental Science; Louisiana State Univ.; Baton Rouge LA 70803
4. Dep. of Plant Agriculture, Crop Science Bldg.; Univ. of Guelph; Guelph ON Canada N1G 2W1