Centric fusion between nonhomologous rye chromosomes in wheat

The frequency of centric fusion has been compared in three wheat–rye double monosomic addition lines. In one plant, designated plant A, both monosomes were bibrachial. In the second plant, B, one monosome was bibrachial and one telocentric. In the remaining plant, C, both monosomes were telocentric. Rye centric fusion chromosomes were identified in the progeny by C-banding mitotic root-tip chromosomes and electrophoresis of endosperm storage protein. Four of 97 analyzed progeny of plant A and 4 of 96 analyzed progeny of plant B possessed centric fusion chromosomes. In contrast, none of the 492 progeny of plant C possessed centric fusion chromosomes. The data indicate that at least one bibrachial monosome is necessary for the efficient production of centric fusion chromosomes.