Introgression of barley chromosome arms 4H and 6H into wheat via Robertsonian translocations: GBS-assisted structural analysis and impact on grain nutrient composition

In addition to wild relatives, cultivated Triticeae species such as barley can also serve as an excellent gene source to improve the agronomic traits of bread wheat. The Asakaze-Manas addition lines previously developed in Martonvásár exhibit low fertility and unstable inheritance; nonetheless, they could serve as ’bridge materials’ for the incorporation of barley chromatin into the wheat genome. By leveraging the centric breakage-fusion mechanism of unpaired chromosomes and the gametocide effect of chromosome 2C from Aegilops cylindrica , the 4H and 6H addition lines were used to develop genetically stable translocation genotypes. In situ hybridization and molecular marker analyses were applied to identify the wheat and barley chromosome arms in the 6HS.6BL, 6BS.6HL and 4BS.4HL compensatory translocations. These results were confirmed by GBS read coverage analysis, which revealed a pericentric inversion in the barley chromosome arms involved in the 6HS.6BL and 6BS.6HL translocations. The comparable agronomic performance of the centric fusion lines indicates that these chromosomal rearrangements had minimal, if any, negative impact relative to the parental wheat varieties. The newly developed translocation lines had an increased amount of certain minerals (Ca or Fe), suggesting that they could serve as promising genetic materials for the biofortification of hexaploid wheat.