Cultivated barley belongs to the tertiary genepool of hexaploid wheat. Genes of interest can be transferred from barley into wheat through wide hybridization. The application of wheat-barley introgression lines could provide an excellent tool for the transfer of earliness, favourable amino acid composition, biotic stress resistance, abiotic stress tolerance, or good tillering ability into wheat. A set of 10 wheat-barley ditelosomic addition lines (2HS, 2HL, 3HS, 3HL, 4HS, 4HL, 6HS, 6HL, 7HS and 7HL) was developed from the progenies of an Asakaze/Manas wheat-barley hybrid produced in Martonvásár, Hungary. The addition lines were selected from self-fertilized plants of the BC2F2-BC2F4 generations using genomic in situ hybridization (GISH) and were identified by fluorescence in situ hybridization (FISH) with repetitive DNA probes [HvT01, (GAA)7 and centromere-specific (AGGGAG)4 probes]. The cytogenetic identification was confirmed using barley arm-specific SSR and STS markers. The ditelosomic additions were propagated in the phytotron and in the field, and morphological parameters (plant height, tillering, length of the main spike, number of seeds/spike and seeds/plant, and spike characteristics) were described. In addition, the salt stress response of the ditelosomic additions was determined. The six-rowed winter barley cultivar Manas is much better adapted to Central European environmental conditions than the two-rowed spring barley Betzes previously used in wheat-barley crosses. The production of wheat-barley ditelosomic addition lines has a wide range of applications both for breeding (transfer of useful genes to the recipient species) and for basic research (mapping of barley genes, genetic and evolutionary studies and heterologous expression of barley genes in the wheat background).

Interspecific hybridization between bread wheat (Triticum aestivum, 2n = 42) and related species allows the transfer of agronomic and quality traits, whereby subsequent generations comprise an improved genetic background and can be directly applied in wheat breeding programmes. While wild relatives are frequently used as sources of agronomically favourable traits, cultivated species can also improve wheat quality and stress resistance. A salt-tolerant ‘Asakaze’/‘Manas’ 7H disomic addition line (2n = 44) with elevated β-glucan content, but with low fertility and an unstable genetic background was developed in an earlier wheat-barley prebreeding programme. The aim of the present study was to take this hybridization programme further and transfer the favourable barley traits into a more stable genetic background. Taking advantage of the breakage-fusion mechanism of univalent chromosomes, the ‘Rannaya’ winter wheat 7B monosomic line was used as female partner to the 7H addition line male, leading to the development of a compensating wheat/barley Robertsonian translocation line (7BS.7HL centric fusion, 2n = 42) exhibiting higher salt tolerance and elevated grain β-glucan content. Throughout the crossing programme, comprising the F₁-F₄ generations, genomic in situ hybridization, fluorescence in situ hybridization and chromosome-specific molecular markers were used to trace and identify the wheat and barley chromatin. Investigations on salt tolerance during germination and on the (1,3;1,4)-β-D-glucan (mixed-linkage glucan [MLG]) content of the seeds confirmed the salt tolerance and elevated grain MLG content of the translocation line, which can be directly applied in current wheat breeding programmes.

During interphase, the chromosomes of eukaryotes decondense and they occupy distinct regions of the nucleus, called chromosome domains or chromosome territories (CTs). In plants, the Rabl’s configuration, with telomeres at one pole of nucleus and centromeres at the other, appears to be common, at least in plants with large genomes. It is unclear whether individual chromosomes of plants adopt defined, genetically determined addresses within the nucleus, as is the case in mammals. In this study, the nuclear disposition of alien rye and barley chromosomes and chromosome arm introgressions into wheat while using 3D-FISH in various somatic tissues was analyzed. All of the introgressed chromosomes showed Rabl’s orientation, but their relative positions in the nuclei were less clear. While in most cases pairs of introgressed chromosomes occupied discrete positions, their association (proximity) along their entire lengths was rare, and partial association only marginally more frequent. This arrangement is relatively stable in various tissues and during various stages of the cell cycle. On the other hand, the length of a chromosome arm appears to play a role in its positioning in a nucleus: shorter chromosomes or chromosome arms tend to be located closer to the centre of the nucleus, while longer arms are more often positioned at the nuclear periphery.

Keymessage GBS read coverage analysis identified a Robertsonian chromosome from two Thinopyrum subgenomes in wheat, conferring leaf and stripe rust resistance, drought tolerance, and maintaining yield stability. Abstract Agropyron glael (GLAEL), a Thinopyrum intermedium × Th. ponticum hybrid, serves as a valuable genetic resource for wheat improvement. Despite its potential, limited knowledge of its chromosome structure and homoeologous relationships with hexaploid wheat (Triticum aestivum) has restricted the full exploitation of GLAEL's genetic diversity in breeding programs. Here, we present the development of a 44-chromosome wheat/GLAEL addition line (GLA7). Multicolor genomic in situ hybridization identified one chromosome arm from the St subgenome of Th. intermedium, while the other arm remained unclassified. Genotyping-by-sequencing (GBS) read coverage analysis revealed a unique Robertsonian translocation between two distinct Thinopyrum subgenomes, identified as 4StS·1J^vsS. The GLA7 line demonstrated strong adult plant resistance to both leaf rust and stripe rust under natural and artificial infection conditions. Automated phenotyping of shoot morphological parameters together with leaf relative water content and yield components showed that the GLA7 line exhibited elevated drought tolerance compared to parental wheat genotypes. Three years of field trials showed that GLA7 exhibits similar agronomic performance and yield components to the wheat parents. This unique addition line holds promise for enhancing wheat's tolerance to multiple stresses through the introduction of new resistance genes, as well as its ability to mitigate the effects of temporary water limitation during flowering, all without negatively impacting wheat performance.

Grain dietary fiber content is an important health-promoting trait of bread wheat. A dominant dietary fiber component of wheat is the cell wall polysaccharide arabinoxylan and the goatgrass Aegilops biuncialis has high β-glucan content, which makes it an attractive gene source to develop wheat lines with modified fiber composition. In order to support introgression breeding, this work examined genetic variability in grain β-glucan, pentosan, and protein content in a collection of Ae. biuncialis. A large variation in grain protein and edible fiber content was revealed, reflecting the origin of Ae. biuncialis accessions from different eco-geographical habitats. Association analysis using DArTseq-derived SNPs identified 34 QTLs associated with β-glucan, pentosan, water-extractable pentosan, and protein content. Mapping the markers to draft chromosome assemblies of diploid progenitors of Ae. biuncialis underlined the role of genes on chromosomes 1M^b, 4M^b, and 5M^b in the formation of grain β-glucan content, while other QTLs on chromosome groups 3, 6, and 1 identified genes responsible for total- and water-extractable pentosan content. Functional annotation of the associated marker sequences identified fourteen genes, nine of which were identified in other monocots. The QTLs and genes identified in the present work are attractive targets for chromosome-mediated gene transfer to improve the health-promoting properties of wheat-derived foods.