Abstract
With the aim of transferring the leaf rust resistance of Triticum Timopheevi to common wheat, a cross was made between them by using the former species as female parent, and from 2 cross combinations 9 mature F1 plants were obtairied. In the root-tip cells of all F1 plants, the number of somatic chromosomes was confirmed to be 35, which cor.responds to the sum of reduc, ed numbers of their parents (T. Timopheevi (n= l 4) +T.vulgare(n = 21 ) = 35) . At MI in meiosis of PMC's of these F1 plants, far more univalents were observed than in the usual wheat pentaploid hybrids with Emmer, group, and correspondingly the number of bivalents to be inet with has been decreased. Some multivalents were often observed up to quinquivalent, above all, trivalent being frequently met with. The results obtained are given in Table 2 and 3.Laggards and bridges were frequently observed in anaphase of both 1st and 2nd divisions. Dyads or polyads were not observed, but pollen tetrads normal in shape with many micronuclei were formed considerably frequent. The highest number of micronuclei contained in the monospore of a pollen tetrad is 5, the mode being in I in F1-a. O in F1-b.
