MATHEMATICS OF CHROMOSOME PAIRING

C. J. Driscoll ¹, G. H. Gordon ¹, and G. Kimber ²

¹ Department of Agronomy, Waite Agricultural Research Institute, The University of Adelaide, Glen Osmond, South Australia 5064 Australia
² Department of Agronomy, The University of Missouri-Columbia, Columbia, Missouri 50625

Analysis of frequencies of chromosome configurations in wheat-related species hybrids is extended to include cases involving homoeologous groups of size six. Further, the expected frequencies of the various configurations emanating from homologous and homoeologous pairing events have been determined for groups consisting of two and three homoeologous pairs of homologous chromosomes. Analysis of configuration frequencies of nullisomic 5B of wheat, in which both homologous and homoeologous pairing occurs, led to estimation of the relative frequencies of homologous and homoeologous pairing events as 17.9:1. In the samples analyzed, slightly less than one homoeologous exchange occurred per gamete.