Fig. 2.

(a-b) A somatic cell of Hybrid 33 (6x T. ambiguum x 2x T. occidentale) showing 2n = 4x = 32 chromosomes. a DAPI stained cell in grey scale. Dotted guidelines represent decondensed NORs. b FISH on the same cell using 5S (pink) and 35S (green) rDNA probes. In both a and b, NOR chromosomes from T. ambiguum (green arrows) and T. occidentale (yellow arrowheads) are indicated. A red arrowhead identifies a T. occidentale chromosome with a minor 5S signal. In b, red arrows indicate T. ambiguum chromosomes with large 5S signals. c-d A somatic cell of an OP progeny plant of hybrid 33 (Hybrid 33OP-1). c DAPI stained cell in grey scale. Dotted guidelines represent decondensed NORs. d FISH on the same cell using 5S (pink) and 35S (green) rDNA probes. In both c and d, NOR chromosomes from T. ambiguum (green arrows) and T. occidentale/ T. repens (yellow arrowheads) are indicated. Red arrowheads identify T. occidentale/T. repens chromosomes with 5S signals. In d, red arrows indicate T. ambiguum chromosomes with large 5S signals