Characteristics and behaviour of the chromosomes of Leymus mollis and L. racemosus (Triticeae, Poaceae) during mitosis and meiosis.

Leymus mollis and L. racemosus (Triticeae; Poaceae) are important as genetic resources for wheat improvement, as they carry genes for salt tolerance and disease resistance. Even though these species share common Ns and Xm genomes, the genomic relationship between these two species is not yet clearly understood. In this study, we examined the genomes of the two species by FISH and GISH, using combinations of tandem-repetitive sequences and genomic DNAs. Comparative GISH showed that genomes in the genus Leymus were diverse. Nevertheless, chromosomes of these two species were able to undergo complete meiotic pairing in hybrids, suggesting that differences in the subtelomeric heterochromatin and sequences distinguishable by GISH do not affect meiotic pairing.