No 5-B compensation by rye B-chromosomes.

Chinese Spring mono-5B wheat was crossed with rye plants, with and without B-chromosomes, to produce polyhaploids with and without 5B and with and without rye B-chromosomes. As expected, absence of 5B resulted in a strong increase of homoeologous pairing. It was accompanied by a decrease in chiasmata in the rye B-chromosomes.