1. Dep. of Agronomy and Horticulture Univ. of Nebraska‐Lincoln Lincoln NE 68583 USA
2. Dep. of Horticulture and Crop Science The Ohio State Univ. Columbus OH 43210 USA
3. Eastern Nebraska Research and Extension Center Univ. of Nebraska‐Lincoln Ithaca NE 68033 USA
4. Dep. of Agronomy Kansas State Univ. Manhattan KS 66506 USA
5. Dep. of Agronomy Purdue Univ. West Lafayette IN 47907 USA