1. Cornell Univ.Dep. of Crop and Soil SciencesIthacaNY14853
2. Bioforsk‐ Norwegian Institute for Agricultural and Environmental ResearchSaghellinga A, Frederik A. Dahls vei 20, 1432 ÅsNorway
3. Oregon State Univ.Columbia Basin Agricultural Research CentreP.O. Box 370PendletonOR97801