1. Tamworth Centre for Crop Improvement, Tamworth NSW 2340 Australia.
2. Corresponding author. E-mail: mike.sissons@agric.nsw.gov.au Phone: 61 267 631 119. Fax: 61 267 631 222.
3. BRI Australia Ltd., North Ryde, NSW 2113 Australia.
4. Quality Wheat CRC Ltd., North Ryde NSW 2113 Australia.