Enhancing wheat β-glucan content through precision crossbreeding: development and evaluation of biofortified lines with improved nutritional and agronomic traits

<b>Introduction:</b> To address the urgent demand for biofortified wheat enriched with health-beneficial dietary fibres such as β-glucan, this study employed meticulous crossbreeding between established wheat cultivars and the β-glucan-rich wild relative <i>Aegilops kotschyi</i> accession "AK-3790". <b>Methods:</b> Within this context, a derivative line encompassing a pair of 7U chromosomes from <i>Ae. Kotschyi</i>, denoted as 63-2-13, was identified. The presence of the 7U chromosome in this line was confirmed through comprehensive molecular marker and genomic <i>in situ</i> hybridization (GISH) analyses. With the aim of increasing the β-glucan content in hexaploid wheat, two distinct backcross populations were developed utilizing the 63-2-13 line as the donor parent and two separate recurrent parents (WH1105 and HD3086). These populations underwent an exact selection regimen, encompassing parent-like phenotypes, heightened yield, and robust resistance to yellow rust, meticulously tracked across successive generations until the BC₂F_2:3 stage. <b>Results and Discussion:</b> Notably, among the outcomes, selected BC₂F_2:3 progenies presented remarkable increases in β-glucan levels, with a notable increase (BC₂F_2:3 23-5) resulting in an impressive increase in the 1.76% grain β-glucan content. Despite a discernible reduction in yield compared with their high-yielding counterparts, BC₂F_2:3 23-5 demonstrated a harmonious trait profile, encompassing heightened β-glucan content and moderate yellow rust resistance, thus positioning it as a compelling candidate for subsequent refinement endeavors. This research notably underscores the substantial potential of precise introgression strategies for increasing the β-glucan content in wheat, thereby underscoring the imperative of adept trait optimization to ensure both yield stability and nutritional enhancement.