|Budget Amount *help
¥6,800,000 (Direct Cost: ¥6,800,000)
Fiscal Year 1987: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1986: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1985: ¥3,800,000 (Direct Cost: ¥3,800,000)
Although a large number of institutions and researchers were involved for many years in breeding hybrid wheat using Triticum timopheevi cytoplasm and fertility-restoring genes for this cytoplasm, no success of hybrid wheat has reported so far. Mukai and Tsunewaki (1979) proposed to use the cytoplasm of Aegilops kotsuchyi, instead of the timopheevi cytoplasm, enumarating the advantages of the former's over the latter's use. The present project has aimed to develop a new male sterilityfertility restoration system for hybrid wheat breeding, utilizing the kotschyi cytoplasm. For the past three years period, the following experiments were conducted:
(1) Production of a male sterile line with the kotsuchyi cytoplasm --- (Ktschyi)-Spelta was backcrossed three times to a common wheat, Chinese Spring, as a recurrent pollen parent. After each backcross, the hybrids, were self-pollinadted, and the segregating male sterile offspring were used as the female parent for further backcross. Frequency of
the male steriles was very low (less than 1%) in all selfed generations. The male sterile plants in the B3S generation were crossed to a maintainer lins, 911B, developed by Dr. J. panayotov, Bulgaria., This cross produced a uniform, malesterije Fl Jine.
(2) Production of the maintaine lines --- About 50 F2 plants of the cross, Spelta x Chinese Spring, were test-crossed to (kotschyi)-Spelta, and at the same time, self-pollinated. By examining selfed seed fertility of the test-crossed progenies, four F2 lines which can be served as the maintainer of the male sterile line having the kotschyi cytoplasm were selected.
(3) Field trial of the triple-cross hybride having the kotschyi cytoplasm --- The male sterile F1 line stated above was crossed to eight Japanese cultivers, and the resultant triple-cross hybrids were tested in an experimental field plot in four replicates. The results demonstrated that the present male sterility-fertility restoration system gave much higher-yielding hybrid wheat than the system utulizing the timopheeve cytoplasm.
1) Completely male sterile line of Spelta wheat having the kotschyi cytoplasm Less