Abstract/Summary

Achieving high wheat breadmaking quality and stability in environmental friendly farming systems will allow to optimize bread production and to reduce the negative impacts of inorganic nitrogen fertilisers on the environment. On the quality aspect, six quantitative trait loci (QTL) effects associated with key quality traits such as the loaf volume and the crumb whiteness were investigated in six NILs of the cross Malacca x Hereward. The six Near-Isogenic sets of lines (NILs) were grown under two field seasons (2019-2020 and 2020-2021) at Rothamsted in 2m2 plots. The lines of each NILs sets (10) were arranged in vertical sub-blocks (6) with two repetitions(i.e. two sets of six sub-blocks forming two blocks). Standard farming operations were observed and nitrogen fertilisation was applied at a rate of 200 kg.ha-1 . Farinograph and Extensograph tests were carried out on doughs to assess whether the presence of the QTL affects the physical properties of the dough. The QTL traits were measured on bread (loaves volume) and slices of breads (crumb whiteness and number of cells) and the means of the allelic pairs were compared using ANOVA. QTL 4D-2 effect on the whiteness of the crumb was confirmed in the Rothamsted 2019-2020 trials and a candidate gene (TRAESCS4D02G294100) encoding a Lipoxygenase was identified in the QTL region. For the five remaining QTL, the comparisons of the allelic pairs were not significant at a threshold of 5% in the Rothamsted 2019-2020 trial. Regarding the sustainability part, a complex interval mapping (CIM) QTL analysis was performed to dissect the genetic architecture of the traits grain protein deviation (GPD), grain yield (GY), and grain protein content (GPC), and seven senescence metrics using 109 doubled haploid (DH) lines of Malacca x Hereward as mapping population. The 109 double haploid lines of the cross Malacca and Hereward were grown under three field seasons at Rothamsted in 2019-2020 and Reading 2020-2021 and 2021-2022 in 7.47m2 plots. In Rothamsted, the lines were arranged in an balanced incomplete block design with three blocks of size 100 and in Reading they were laid out in a complete randomised block design with three blocks of size 109. The lines were sown at a density of 250 seeds.m-2 and fertilised with 150 kg N.ha-1 . A total of 52 QTL were detected for all traits in all environments. Seven GPD QTL were discovered and one was detected over two field seasons without pleiotropic effect on GY.