Further manipulation by centric misdivision of the 1RS.1BL translocation in wheat

Abstract

Complete chromosomes 1R and 1B were reconstructed in wheat from the centric wheat-rye translocation 1RS.1BL. Three substitutions: 1R(1A), 1R(1B), 1R(1D), and three new centric translocations: 1RS.1AL, 1RS.1BL, 1RS.1DL were produced from the reconstructed chromosome 1R. Each one of these has the same rye chromosome arm 1RS which was present in the original translocation 1RS.1BL of ‘Kavkaz’ wheat. Reconstructed chromosome 1B and a normal chromosome 1R were used to produce a new 1RS.1BL translocation. This translocation has the long arm from the original 1RS.1BL translocation of ‘Kavkaz’, but a different 1RS arm. The third generation centric translocations were mitotically stable and were normally transmitted to progeny. Misdivision frequency of the reconstructed chromosomes 1R did not change relative to normal 1R, whereas the misdivision frequency of the two reconstructed chromosomes 1B tested was significantly higher relative to normal 1B. These experiments demonstrate that repeated cycles of centric breakage and fusion do not impair the function of centromeres in wheat and rye but may change chromosome's susceptibility to misdivision.