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Genetic Variance for Gluten Strength Contributed by High Molecular Weight Glutenin Proteins¹

¹Agriculture and Agri-food Canada Contribution 1813. ²Agriculture and Agri-Food Canada, Cereal Research Centre, 195 Dafoe Rd., Winnipeg, MB, R3T 2M9, Canada. ³Corresponding author. E-mail: scloutier@agr.gc.ca. Phone: 204-983-8194. Fax: 204-983-4604.

A total of 162 doubled haploid (DH) lines were produced from a cross between Triticum aestivum L. ‘AC Karma’ and line 87E03-S2B1 to study the genetic contribution of high molecular weight (HMW) glutenin subunits to gluten strength. HMW glutenin subunit composition of each DH line was determined by SDS-PAGE. The population was grown in the field at one location in 1999 and at three locations in 2000. Gluten strength and dough mixing properties were measured by mixograph test and SDS-sedimentation test. Variance components were estimated for each measurement to determine the variability contributed by HMW glutenin subunits. Results indicated significant environmental impact on tested mixograph parameters, SDS-sedimentation volumes and grain and flour protein concentration. Significant main effects of Glu-1D loci encoded subunits were obtained for mixograph development time, energy to peak, slope after peak, and first minute slope. Lines containing 5+10 combination of subunits had higher values for mixograph development time and energy to peak, while slope after peak and first minute slope were lower as compared with 2+12 containing lines. Low intergenomic interactions were observed for bandwidth energy (BWE), total energy (TEG), and SDS-sedimentation test, involving B and D genomes only. A portion of the genetic variability for gluten strength was accounted for overexpression of Bx7 subunit originating from the cultivar Glenlea derived line 87E03-S2B1. There was no significant effect of Glu-A1 encoded subunits on any of the tested parameters. Estimated genetic variability for gluten strength contributed by Glu-B1 and Glu-D1 encoded HMW glutenins was 55% for mixing development time and 51% for energy to peak.