Comparative analysis of d and r genomes in two lignes (x-trit-icosecale wittmak) and their genitors (secale cereale l., triticum aestivum l.) by n-banding

Abstract

We were interested in heterochromatic variability analysis of D and R genomes, evidenced by the N-banding technique and the localization of nucleolar organising regions (NOR) in two triticales (2n=8x= 56, AABBDDRR) and their genitors, common wheat (2n=6x=42, AABBDD) and rye (2n=2x=14, RR). The Analysis of N bands of genomes D and R of the hybrids in comparison with their genitors displayed a different marking. In the genome D, hybrid Mahon-demias x RC9 is much less heterochromatic than both genitor Mahon-demias and Mahon-demias x Merced. In the genome R, differencies involved a great deal of heterochromatin in hybrid Mahon-demias x Merced revealed by thick bands. Nevertheless, hybrid Mahon-demias x RC9 is almost similar to its genitor. In the genitors and in the hybrids, the organising regions (NOR) marked on the chromosomes 1R, 2R, 3R and 6R of rye and on the chromosome 1B of wheat and on the chromosomes 1B, 1R, 2R, 3R, 6R of triticales, showed the a same localisation compared with that described by authors. The results indicate the existence of intervarietal polymorphisms in rye and triticale, as well as the presence of chromosomes B of telocentric form or isochromosomes a heterochromatic and / or euchromatic structure. Thereafter, our varieties being cultivated in arid climate conditions, may have a suitable adaptation owing to the presence of B chromosomes. In this case, the presence of B chromosomes could be explained as a manifestation of their adaptation and the rye phenotype is not affected by the presence of B chromosomes. © 2008 Taylor & Francis Group, LLC.