1. Texas Agric. Exp. Stn. Stephenville TX 76401
2. Soil & Crop Sci. Dep.Texas Agric. Exp Stn.Texas A&M Univ. College Station TX 77843
3. Texas Agric. Exp. Stn. Lubbock 79403
4. USDA‐ARS Stillwater OK 74074
5. Texas Coop. Ext.Texas Agric. Res. & Ext. Ctr. Uvalde TX 78802
6. Texas Agric. Exp. Stn. Lubbock TX 79403
7. Oklahoma State Univ. Stillwater OK 74074