Phylogeographic and quantitative trait locus analysis of the ability of Aegilops tauschii Coss., the D genome progenitor of common wheat, to cause genome doubling in the F 1 hybrids with Triticum turgidum L., the AB genome progenitor

Aegilops tauschii Coss. (DD genome) is a wild paternal progenitor of common wheat ( Triticum aestivum L.; AABBDD genome). This species has genetically distinctive intraspecific lineages that differ in their patterns of involvement in allopolyploid speciation of common wheat. Ae. tauschii accessions can cause genome doubling at variable frequencies depending on their genotypes via unreduced gamete production and fusion in the trihaploid F 1 hybrids (ABD genome) with Triticum turgidum L. (AABB genome), the maternal progenitor. In this study, we examined the variation patterns of Ae. tauschii ’s ability to cause hybrid genome doubling based on an artificial cross experiment and attempted to improve on a previous linkage map of loci that control the expression of this ability by using an increased number of anchor markers. According to the results, this ability was genealogically and geographically widespread within the species, suggesting that it might not have been critically involved in shaping common wheat speciation patterns. The weak phylogeographic structure of the trait variation is consistent with the idea that the genes for hybrid genome doubling have some function (most likely, meiotic) in Ae. tauschii and are maintained because of their adaptive importance, whereas genes may accumulate non-deleterious mutations that could positively or negatively influence the expression of genome doubling when placed in the hybrid genome background. The linkage analysis used 1035 anchor markers and identified five loci on chromosomes 2D, 3D, 6D, and 7D that significantly influenced the expression of hybrid genome doubling.