Molecular cytogenetic characterization of Roegneria ciliaris chromosome additions in common wheat

The development of alien addition lines is important both for transferring useful genes from related species into common wheat and for studying the relationship between alien chromosomes and those of wheat. Roegneria ciliaris (2n=4x=28, S^cS^cY^cY^c) is reported to be a potential source of resistance to wheat scab, which may be useful in wheat improvement. The amphiploid common wheat-R. ciliaris and BC₁F₇ or BC₂F₆ derivatives were screened by C-banding, genomic in situ hybridization (GISH), fluorescent in situ hybridization (FISH) and restriction fragment length polymorphism (RFLP) for the presence of R. ciliaris chromatin introgressed into wheat. Six lines were identified as disomic chromosome additions (DA), one as a ditelosomic addition (Dt), two as double disomic additions (dDA) and one as a monosomic chromosome addition (MA). RFLP analysis using wheat homoeologous group-specific clones indicated that the R. ciliaris chromosomes involved in these lines belong to groups 1, 2, 3, 5 and 7. The genomic affinities of the added R. ciliaris chromosomes were determined by FISH analysis using the repetitive sequence pCbTaq4.14 as a probe. These data suggest that the R. ciliaris chromosomes in five lines belong to the S^c genome. Based on the molecular cytogenetic data, the lines are designated as DA2S^c#1, Dt2S^c#1L, DA3S^c#1, dDA1S^c#2+5Y^c#1, DA5Y^c#1, DA7S^c#1, DA7Y^c#1 and MA?Y^c#1. Based on the present and previous work, 8 of the 14 chromosomes of R. ciliaris have been transferred into wheat.