1. Texas A&M Univ.; Research and Extension Center; Rt. 2, Box 589 Corpus Christi TX 78410
2. Dep. of Agronomy; Kansas State Univ.; Manhattan KS 66506
3. Dep. of Agronomy; Univ. of Georgia; Athens GA 30602
4. Agricultural Research Dep., Tennessee Valley Authority; Muscle Shoals AL 35660