Meiosis of wheat x lymegrass hybrids

Meiosis was examined in pollen mother cells of F1 hybrids made from crosses between wheat (Triticum aestivum) and lymegrass (Leymus arenarius and L. m ollis). Fluorescence genomic in situ hybridization detected pairing between wheat and lymegrass chromosomes during prophase I and metaphase I. Such pa iring, when resulting in bivalent formation, was likely to yield correct di sjunction, and hence intergenomic recombination could be incorporated into the gametes. Bivalents in these hybrids, however, were more frequently form ed between chromosomes of the same parental origin. Univalents were common, whereas multivalents were not clearly detected. Meiotic behaviour in some cells was not totally aberrant, and this may have accounted for the presenc e of normal pollen. The results are discussed in relation to intergenomic p airing, meiotic behaviour in wide-hybrids and genome relationships, includi ng the Leymus genome origin.