138 Use of gluten index as a screening tool in durum wheat breeding programs.

N. AMES (1), J. Clarke (2), J. Dexter (3), B. Marchylo (3), and E. Sopiwnyk (1). (1) Cereal Research Centre, Agriculture and Agri- Food Canada, Winnipeg, MB R3T 2M9; (2) Semi-Arid Prairie Research Centre, Agriculture and Agri-Food Canada, Swift Current, SK S9H 3X2; (3) Grain Research Laboratory, Canadian Grain Commission, Winnipeg, MB R3C 3G8.

Gluten index values were determined on whole meal, semolina and flour samples from a number of durum wheat cultivars to assess the variability associated with gluten index measurements and to compare values obtained with various particle sizes. Gluten index wash method (1 or 2 stage) and screen size (80 or 88 micron) was also considered. Gluten index measurements were carried out on whole meal samples from a large number of durum wheat breeding lines to determine the effects of genotype and environment on gluten index values. Results showed within sample variability depended on particle size, wash method and wash screen size. For samples tested using whole meal material, cultivar effects were greater than year effects suggesting gluten index is an effective breeding tool for differentiating strong and weak gluten types. The best combination of wash method, screen size and sample particle size is discussed.