| The chromosome association between Triticum urartu
and other diploid or tetraploid wheats1) Yoshitada YAMAGISHI and Masatake TANAKA Plant Germ-plasm Institute, Facutly of Agriculture, Kyoto University, Kyoto, Japan A number of workers have been discussing the donor of the B1 or G-genome to the tetraploid wheats. JOHNSON (1975) suggested that Triticum urartu Tum. is the donor of the B-genome. However, JOHNSON's hypothesis has been recently claimed by several authers (CHAPMAN et al. 1976, DVORAK 1976, and GERLACH 1977). The purpose of the present paper is to shed more light on the cytogenetical relationships between T. urartu and other wheat species. Materials and Methods The following ten strains of T. urartu were used:
The following eight strains including six wheat species were also used as testers: Einkorn group - Two strains (101-1 and 3620) of T. boeoticum, one strain (104) of T. monococcum., Emmer group - one strain (108-3) of T. dicoccoides, one strain (125) of T. durum, Timopheevi group - two strains (196-1 and 196-2) of T. araraticum, one strain (107-1) of T. timopheevi. All materials have been maintained at the Plant Germ-plasm Institute, Faculty of Agriculture, Kyoto University. The crosses were made between T. urartu and other diploid Einkorn group, and between T. urartu and tetraploid species of the Emmer group or the Timopheevi group. The F1 hybrids obtained from these crosses, were grown in the glasshouse and field. They were examined cytogenetically and physiologically. For the cytogenetical observations, young anthers of these hybrids were fixed in Farmer's solution. Chromosome association was observed at MI of PMC's using the aceto-carmine squash method. About 30 cells per hybrid plant were usually observed. The pollen fertility of the hybrids was assessed after staining them with aceto-carmine solution. Seed fertility was calculated from seed setting on the lowest floret of the spikelets of three bagged spikes. Results and Discussion The interspecific crosses as shown Table 1 were carried out. In four crosses having T. urartu as the female parent, T. urartu x T. boeoticum, T. urartu x T. monococcum, T. urartu x Emmer, and T. urartu x Timopheevi the germination rate was extremely low, 8.0%, 3.0%, 2.3%, and 1.6%, respectively. Almost all seedlings died at the early stage of growth. But in only one cross combination, T. urartu x a strain (3620) of T. boeoticum, a high germination rate was observed and seventeen mature plants were obtained. These hybrid plants were very vigorous, but showed complete pollen sterility and set no seeds. However, normal and viable seeds were produced by backcross hybrids, (T.urartu x T.boeoticum) x T. urartu and (T. urartu x T. boeoticum) x T. boeoticum, as shown in Table 2. The backcross hybrids, (T. urartu x T. boeoticum) x T. urartu, showed 49.9% in pollen fertility and 25% in seed fertility. The chromosome association was 0.04I+6.98II: The other backcross hybrid, (T. urartu x T. boeoticum) x T. boeoticum, showed 78.3%, 41%, and 0.06I+6.97II, respectively (Table 2). |
| 1) Contribution No.15 from the Plant Germ-plasm Institute, Faculty of
Agriculture, Kyoto University. 2)The Botanical Expedition to the Northern Highland of Mesopotamia, Kyoto University, 1970. |
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