1. Agriculture and Food CSIRO LMB 59 Narrabri NSW 2390 Australia
2. Sydney Institute of Agriculture School of Life and Environmental Sciences Faculty of Science The University of Sydney Sydney NSW 2006 Australia
3. USDA Plant Stress and Water Conservation Laboratory Big Spring TX 79720 USA
4. Hawkesbury Institute for the Environment Western Sydney University Richmond NSW 2753 Australia
5. Cropping Systems Research Laboratory USDA Lubbock TX 79415 USA