1. Centre for Microscopy and Microanalysis, University of Western Australia, Crawley 6009, Australia.
2. School of Biological Sciences and Biotechnology, Murdoch University, Perth 6150, Australia.
3. Agronomy Department, Faculty of Agriculture, Chiang Mai University, Chiang Mai 50200, Thailand.
4. Corresponding author: Phone: 665-394 4621. Fax: 665-321 0000. E-mail: agosjmjd@chiangmai.ac.th; g4368102@cm.edu