| Agropyron Agropyron is the largest and most interesting genus because it is not only related closely to Triticum but also to Elymus. Some species of Agropyron are hybridized with Triticum, and others with Hordeum. This indicates that Agropyron is the transition between wheat and barley. It involves more than 100 species which are distributed in different geographical regions and ecological localities in the temperate zone of the world. Among nine species found in Japan, Ag. caninum L. and Ag. repens P. Beauv., are known to be introduced, while the remaining seven species ate indigenous. Two indigenous species, Ag. tsukushiense var. transiens Ohwi (2n=42) and Ag. ciliare var. minus Ohwi (2n=28) are somewhat polymorphic and are found commonly almost everywhere in Japan, while the distribution of other species is comparatively restricted. Ag. Mayebaranum Honda (2n=42) is rarely found in the paddy field or in the ditch of paddy field side from Kanto to Kyushu. It is very, interesting that this species is adapted to such moist places, while almost all species of Hordeae are rather adapted to the drier places. Ag. yezoense Honda (2n=28) is mainly distributed in the forest of Hokkaido, and rarely found in mountain region of Honshu. Ag. Gmelini var. tenuisetum Ohwi also rarely occurs in mountain region of Honshu. Ag. caninum L. is found only in Mt. Ibuki. Ag. rapens is found in Hokkaido and sometimes in Honshu. Ag. Hatusimae Ohwi (2n=42) is sterile and of intermediate type between Ag. Mayebaranum and Ag. tsukushiense, and, therefore, it is considered that this species is the hybrid between the two species. Genome analysis in the Japariese species : Japanese Agropyron is not hybridized with Triticum but the hybridization between species of Japanese Agropyron is possible. As the results of their cytological investigation the genome formulae have been determined. The pentaploid hybrid between Ag. tsukushiense (IKL) and Ag. ciliare (IK) is completely sterile, though two species have two common genomes. The sterility was also observed in the other specific hybrids, Ag. yezoense (IyKy) x ciliare (IK) and Ag. Mayebaranum (Im??) x Ag. tsukushiense (IKL). F1 hybrids between Triticum species and Ag. intermedium (2n=42) or elongatum (2n=70): Three species of Agropyron, Ag. elongatum, intermedium and trichophorum, easily hybridize with Triticum, except Einkorn wheats. We can obtain, however, the F1 hybrids between induced tetraploid T. aegilopoides and Agropyron species. When Agropyron intermedium was used as Agropyron parent, the hybrids show the intermediate characteristics between their parents, while when Agropyron elongatum was used the hybrids resemble closely the. Agropyron parent. Most of the chromosome conjugations at the ineiosis of F1 hybrids, should be attributed to the autosyndesis of Agropyron chromosomes. In many cases, the F1 hybrids are sterile due to the meiotic irregularities, but a few seeds can be obtained from backcrosses. |
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