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.