| Budget Amount *help |
¥9,600,000 (Direct Cost: ¥9,600,000)
Fiscal Year 1990: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1989: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 1988: ¥5,400,000 (Direct Cost: ¥5,400,000)
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| Research Abstract |
A common wheat having the 1B-1R translocation chromosome of Salmon wheat and an S^v cytoplasm of Aegilops kotschyi or Ae. variabilis produces haploids at a high frequency. However, when they are chromosome-doubled, only malesterile plants are obtained, which have no breeding value. In this project we aimed to develop a genetic system with which we can get haploids producing male-fertile plants when chromosome-doubled. The following two approaches have been undertaken : (1) Induction of a mutation from PM to SS= to inactivate the function of Spq suppressing the Ptg gene for haploid induction. (2) Screening of the Rfvl spg genotype among common wheat cultivars carrying a 1B-lR translocation@hromosome. The results obtained are as follows :
(1) Screening of the mutation, SSM to spg, among mutagen-treated common wheat --- Presoaked seeds of a common wheat CS were treated with 0.2-0.6% EMS, and their M_2 offspring were crossed as male to alloplasmic lines of Salmon with an S^v type cytoplasm
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(abbrev. (S^v)-Salmon). In the next generation seed fertility of the individual plants were observed and haploid frequency in their offspring was tested. In total, 715 M_2 lines were tested, and some lines showing high haploid frequency were obtained. Unfortunately, all these lines showed very low fertility, and we could not get any mutant line having the expected genotype, Rfvl spg.
(2) Screening the Rfvl spq genotype among wheat cultivars carrying a 1B-lR translocation --- In total 26 cultivars were crossed as male to (S^v)-CS, and Fl hybrids were backcrossed to those cultivars as female parent. In the Bl generation seed fertility of about 15 plants per line and haploid frequency in their offspring were observed. Almost all cultivars produced the Bi offspring of high fertility with no haploids or low fertility with high haploid frequency. Only exception was a line XXXXXX bred by CIMMYT, that gave the Bl line with high fertility and high haploid frequency. We assume this particular line has the genotype, Rfvl spg, that we have been looking for.
Note) The name of the CIMMYT line will not be publicized. Less
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