抄録
Two morphologically distinguishable types of Triticum araraticum were crossed to each other and with other tetraploid wheats of nine taxa belonging to Timopheevi and Emmer groups. Crosses were also made between T. timopheevi and two wild Emmer taxa and between a wild taxon and a cultivated taxon of Emmer group. The F1 hybrids obtained from these crosses were examined cytogenetically. It was shown that T. araraticum is very close to T. timopheevi cytologically. One of the two types of T. araraticum (KU 196-2) was proved to have an almost identical chromosome structure with T. timopheevi, while the other (KU 196-1) was shown to have a chromosome structure different from those of the above two at least by a translocation. The F1 hybrid between T. araraticum KU 196-2 and T. timopheevi was fertile, being contrary to the most of the earlier reports. Irregular meiosis, less chiasmata and complete sterility were the characteristics of the F1 hybrids between Timopheevi and Emmer groups. More univalents and less chiasmata were observed in the hybrids of the KU 196-1 stock of T. araraticum with Emmer wheats than in those of the KU 196-2. Also, more univalents and less chiasmata were generally observed in the hybrids of T. araraticum with wild Emmer wheats than in those with cultivated Emmer wheats. Based on these results and earlier reports, it was concluded that the structural differentiation of chromosomes must have acted an important role in the evolutionary courses of the tetraploid wheats which originated from probably a single ancestor.
