Effect of Glu-D1 gene introgression and amylose content on breadmaking potential of blends of durum and hexaploid wheat

Background and objectives Durum wheat is used to make leavened bread; however, durum bread has inferior loaf volume, structure, and texture compared to bread made from common wheat. One approach to overcome this is to transfer key storage protein genes present at the Glu-D1 locus from bread wheat into durum. Durum wheat Svevo missing Glu-B1subunits 7 + 8 and Lira biotypes with low molecular weight glutenin subunits types 1 and 2 were evaluated for their breadmaking potential with and without high molecular weight glutenin subunits 2 + 12 or 5 + 10. Findings Bread made from blends of durum and a commercial baker's flour (10%, 25%, 50% w/w) assessed over two seasons in 10 different genotypes showed that as more durum was included in the mixture, loaf volume and texture score declined. Incorporation of the 2 + 12 subunit pair in the genotypes Lira42 and Lira45 improved bread quality but not in Svevo, whereas including 5 + 10 improved bread quality of Lira42 had no effect on Lira45 but reduced quality of Svevo. Low amylose Svevo had similar loaf quality to Svevo while adding 5 + 10 had minimal impact except at 50% with a small improvement in loaf quality. Bread stored up to 7 days became firmer partly due to increased starch retrogradation, and loaves were similar to bread made from baker's flour. Low amylose Svevo kept the loaf fresher but only up to 3 days of storage. Subunit pair 5 + 10 made the loaf firmer after 7 days compared to control. Conclusions Addition of the 2 + 12 or 5 + 10 benefited the weaker type gluten as found in Lira 42 (LMW-1, HMW 20) but not with stronger dough in Svevo even in the absence of HMW 7 + 8. It appears that while Glu-D1 subunits are critical for good breadmaking in hexaploid wheat, they appear to have limited value in improving loaf volume and structure in durum bread. <t Significance and novelty: Some improvements in bread quality can be obtained by introducing genes coding for Glu-D1 subunits 2 + 12 and 5 + 10 in durum wheat depending on the genotype, especially weak dough types, and the results presented comprise the first report of such effect.