Analysis of the effect of rye chromosomes 4R, 6R and telomeric heterochromatin on 7R on homologous chromosome pairing in pentaploid hybrids (AABBR, AABBD)

Meiotic pairing in Triticum turgidum cv. Ma (4x) with a mean chiasmata frequency of 27.16 per cell was compared with chiasmata frequencies in its hybrids with several triticale strains, 'Chinese Spring' wheat and its addition lines for 'Imperial' rye chromosomes 4R and 6R. In hybrids between 'Ma' and x Triticosecale cv. 'Rosner' the chiasmata frequency was marginally reduced by an average of 1.25%, by 8.8% in hybrids with x Triticosecale cv. 'DRIRA' HH and by 6.7% with 'DRIRA' EE (lacking 90% telomeric heterochromatin from chromosome arm 7RL). In pentaploid hybrids between 'Ma' and T. aestivum cv. 'Chinese Spring' the reduction was an average of 10.30%, while addition lines with rye chromosome 6R reduced chiasmata frequencies by an average of 7.4% and rye addition line for 4R showed the greatest depression in chiasmata frequency in hybrids by a 25.04% reduction. An interchange difference involving long chromosome segments was observed between 'Ma' and 'Rosner'