| An F1 hybrid between T. durum 8x
and Agropyron trichophorum Mikio MURAMATSU Laboratory of Genetics, FacuIty of Agriculture, Kyoto University, Kyoto, Japan An F1 hybrid between induced Triticum durum var. hordeiforme 8x (AAAABBBB) and Agropyron trichophorum (2n=42) revealed 2n=50, although 2n=49 was expected. The mode of chromosome conjugation at MI is shown in Table 1. Most of the bivalents were of the closed type, but a few of them were of the open type with terminal connection. Fourteen bivalents which conjugated strongly must have been due to autosyndesis of chromosomes belonging to A and B genomes derived from octaploid T. durum. Only one trivalent was observed. This was considered to be due to a gamete having an extra chromosome from octaploid T. durum. This suggests also that no homology exists between the genomes of A. trichophorum and Emmer. The remaining 0-3 bivalents should be due to pairing between the chromosomes of genomes of A. trichophorum, but their number is too small to be attributed to two supposedly homologous genomes of A. trichophorum. This result supports the view that the 3 genomes of A. intermedium, which seems to have the same genome constitution with A. trichophorum, are not homologous (Muramatsu 1955, WIS No. 2). Pollen-fertility was 20.4% and one seed was obtained from artificial self bollination. The somatic chromosome number of this F2 plant, examined in root tip cells, was 2n=54. |