A Study of the Rheological Properties and Gluten Protein Components Associated with Enhanced Baking Quality in Durum Wheat (Triticum turgidum L. var. durum)

Durum wheat (Triticum turgidum L. var. durum, 2n = 4x = 28, AABB genomes) is used predominantly for semolina and pasta products, but there is increasing interest in using durum for bread-making to provide alternative markets during periods of overproduction. The goal of this study was to characterize the bread-making quality of durum wheat cultivars and emmer (Triticum turgidum L. var. dicoccum, 2n = 4x = 28) derived breeding lines derived from crosses of durum wheat with an Emmer land race ‘97Emmer19’ from Iran. Emmer-derived breeding lines were evaluated along with three high quality bread wheat (Triticum aestivum L., 2n = 6x = 42, AABBDD genomes) cultivars and seven durum wheat cultivars across three environments in replicated yield trials in the 2005 and 2006 growing seasons. Four 1AS.1AL-1DL translocation lines which carry the Glu-D1d allele [high molecular weight glutenin subunit (HMW-GS) pair 1Dx5+1Dy10] from chromosome 1D of bread wheat were also evaluated. In general, durum wheat cultivars with elevated gluten strength and/or increased dough extensibility were noted to have higher loaf volume (LV) than those with weaker gluten. The 1AS.1AL-1DL translocation line ‘L252’ carrying the LMW-1 banding pattern had better dough mixing stability and LV than the translocation lines with the LMW-2 banding pattern. The 1AS.1AL-1DL translocation lines had higher grain protein concentrations (GPC), but the lowest loaf volumes of all the lines tested. These translocation lines also exhibited unappealing external loaf quality (loaf shape and appearance) and poor internal loaf quality (crumb structure). Variation in bread-making quality attributes were observed among durum genotypes. ‘97Emmer19’ exhibited higher LV than all the durum wheats evaluated and approached the loaf volume achieved with the bread wheat cultivar ‘AC Superb’. Breeding lines derived from crosses of ‘97Emmer19’ to strong gluten durum cultivars (‘WB881’ or ‘AC Navigator’) had higher LV than those of the durum checks. ‘97Emmer19’ carried Glu-A1a* (HMW-GS 1Ax1) and the progeny carrying that allele generally exhibited higher loaf volumes. Durum wheat genotypes expressing the Glu-B1d (HMW-GS pair Bx6+By8) allele exhibited better overall bread-making quality compared with those expressing the Glu-B1b (HMW-GS pair Bx7+By8) allele. The durum cultivar ‘Arcola’ and the emmer-derived breeding line ‘2000EB4’, showed higher alveograph extensibility (L) values than did the bread wheat check ‘AC Barrie’. The durum wheat genotypes (with the exception of ‘Stewart-63’) and emmer-derived breeding lines exhibited better dough extensibility than the USDA-ARS 1AS.1AL-1DL translocation lines. These results indicate that there is potential to select for genotypes with improved baking quality in durum breeding programs