Determination of quantitative trait loci for SDS sedimentation value and glutenindex in durum using double haploid population

Gluten strength, is an important factor in pasta manufacture and cooking quality and thus an important selection criterion in durum (Triticum turgidum L. var durum) cultivar development. DNA markers are useful tools for assessing genetic loci involved in complex traits and should assist our understanding of gluten strength. A doubled haploid population segregating for gluten strength was developed using the maize pollen method from the cross (Kyle*2/Biodur)/Kofa, wherein the Kyle*2/Biodur parent (an F9 line) has conventional gluten strength and Kofa has very strong gluten. The SDS-sedimentation test is used extensively by durum breeders because of the small sample size required and the rapidity of measurement. More recently, the gluten index has been applied to early generation selection as well as in pasta industry laboratories. We assessed the response of the two measures of gluten strength to environmental conditions in durum wheat samples from replicated field trials grown at one and three locations typical of the durum production area of western Canada in 2000 and 2001 respectively. Gluten index and SDSsedimentation volume were determined by standard methods. Data were analyzed using mixed-model ANOVA to assess differences among genotypes. The population was also tested against wheat microsatellite markers, and QTL analysis of polymorphic markers and measures of gluten stength were assessed using mQTL. In a sparse map, QTL loci were associated with markers on chromosomes 1B and 2A. The 1B locus appeared as highly significant in all locations across both years for both SDS-sedimentation and gluten index. The 2A locus, in contrast, was significant for sedimentation value for two locations in only 2001 and only one of these locations appeared as significant for gluten index. Apparently some loci that contribute to gluten strength are more consistently expressed, while other loci are more ephemeral