Testing the genetic autonomy of the plasmon in the Triticum–Aegilops complex: The final work of Prof. Koichiro Tsunewaki

Prof. Tsunewaki dedicated his entire scientific career toward understanding the genetic effects and the diversity of “plasmon”, the whole cytoplasmic genetic system, in the common wheat Triticum and its relative Aegilops. He concluded his life’s work with a set of final experiments to test the genetic autonomy of the plasmon in this complex. They were represented by two interconnected studies. First, the examination of the persistence of genetic effects of Ae. caudata plasmon on the phenotype of the common wheat, Triticum aestivum strain “Tve” (genome: AABBDD) during 63 generations of repeated backcrosses with Tve pollen. The second study involved the reconstruction of an Ae. caudata strain by replacing the nuclear genome of the alloplasmic Tve mentioned above, (caudata)-Tve SB50, with the genome (CC) of Ae. caudata. In this experiment, he tested whether there are any differences between the native plasmon of Ae. caudata and the caudata plasmon that had remained in common wheat for more than 60 generations. This paper reviews the outline and background of the last work of Prof. Koichiro Tsunewaki.