Wheat–barley hybridization: the last 40 years

Several useful alien gene transfers have been reported from related species into wheat (Triticum aestivum), but very few publications have dealt with the development of wheat/barley (Hordeum vulgare) introgression lines. An overview is given here of wheat × barley hybridization over the last forty years, including the development of wheat × barley hybrids, and of addition and translocation lines with various barley cultivars. A short summary is also given of the wheat × barley hybrids produced with other Hordeum species. The meiotic pairing behaviour of wheat × barley hybrids is presented, with special regard to the detection of wheat–barley homoeologous pairing using the molecular cytogenetic technique GISH. The effect of in vitro multiplication on the genome composition of intergeneric hybrids is discussed, and the production and characterization of the latest wheat/barley translocation lines are presented. An overview of the agronomical traits (β-glucan content, earliness, salt tolerance, sprouting resistance, etc.) of the newly developed introgression lines is given. The exploitation and possible use of wheat/barley introgression lines for the most up-to-date molecular genetic studies (transcriptome analysis, sequencing of flow-sorted chromosomes) are also discussed.