1. State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences Northwest A&F University Yangling Shaanxi 712100 China
2. Department of Plant Sciences and Plant Pathology Montana State University Bozeman MT 59717‐3150 USA
3. State Key Laboratory of Crop Stress Biology for Arid Areas College of Plant Protection Northwest A&F University Yangling Shaanxi 712100 China
4. CSIRO Agriculture & Food GPO Box 1700 Canberra ACT 2601 Australia