[1] Colorado State Univ, Dept Soil & Crop Sci, Ft Collins, CO 80523 USA
[2] USDA ARS, Natl Lab Genet Resources Preservat, 1111 S Mason St, Ft Collins, CO 80521 USA
[3] USDA ARS, Plant Intro Res Unit, Ames, IA 50011 USA
[4] Iowa State Univ, Dept Agron, Ames, IA 50011 USA
[5] Cornell Univ, Sch Integrat Plant Sci, Plant Breeding & Genet Sect, Ithaca, NY 14853 USA
[6] Univ Wisconsin, USDA ARS, Dept Hort, Vegetable Crops Res Unit, Madison, WI 53706 USA
[7] Iowa State Univ, Dept Agron, Ames, IA 50011 USA