| Meiotic chromosome behaviours and cross-abilities of
some species in the genus Agropyron Y. WATANABE, K. MUKADE and K. KOKUBUN Morioka Experimental Farm, Tohoku Nat. Agr. Exp. Sta, Morioka, Japan Meiotic chromosome behaviours of seven species in the genus Agropyron and their cross-abilities inter se as well as these with common wheat varieties were studied. Name of seven species used and 2n chromosome numbers determined are given in Table 1 together with their sources. Chromosome configurations and their frequencies at MI of PMC's are given in Table 2, and the data on the meiotic chromosome behaviours are computed in Table 3 somewhat in detail. A. elongatum-II and A. campestre, especially the former, showed conspicuous association of multivalent chromosomes because of their high polyploidy, and accordingly variable meiotic configurations were encountered. In the other five species including the basic species, A. elongatum-I, every species except A. junceum-II showed rather variable configurations. Above all, in both A. glaucum and A. trichophorum, the formation of a considerable amount of multivalent and univalent chromosomes were observed. It is interesting to observe some irregularities in the basic species, A. elongatum-I. From the facts described above, it may be said that each genome constituting these species is not wholly different but has more or less homology with each other, and in some cases there must be present semi -homology between some chromosomes of one genome. The cross-abilities of species inter se and these with common wheat varieties were examined about six species except A. junceum-I. In the cross-abilities of species inter se, it was found that three species, A. glaucum, A. junceum-II and A. trichophorum were fertile with each other in both directions. On the other hand, their cross-abilities with common wheat varieties were classified into three groups: High (A. elongatum-II, A. junceum-II and A. trichophorum), Low (A. glaucum and A. campestre) and None (A. elongatum-I). |