| Spelta and Macha become male sterile by the introduction of MAAN's mutica
cytoplasm (Fig. 1) although they have normal 1B
chromosomes. Apparently, their 1B chromosomes do not possess the fertility-restoring
gene, Rfm1, and the genotype can be designated rfm1 rfm1 for
them. MAAN (1977) concluded that the D genome of Selkirk has a fertility-restoring gene (s) for male sterility induced by Ae. mutica cytoplasm, because T . durum with the mutica cytoplasm becomes completely male sterile, whereas Selkirk with the same cytoplasm shows normal fertility. The present results, however, indicate that the gene for fertility restoration for the MAAN's mutica cytoplasm is located on the short arm of chromosome 1B of common wheat but not on a D-genome chromosome. Most likely, T. durum studied by MAAN (1977) possesses the rfm1 allele like our Spelta and Macha. On the other hand, Selkirk is considered to have the Rfm1 allele for fertility restoration. The fertility-restoring gene, Rfm1, for MAAN's mutica cytoplasm might be the same as Rfv1, a fertility-restoring gene for Ae. kotschyi and Ae. variabilis cytoplasms, and Rfun1, a fertility-restoring gene for Ae. uniaristata cytoplasm, because all the three genes locate on the short arm of chromosome 1B of Chinese Spring (MUKAI & TSUNEWAKI 1979 ; MUKAI 1984), and because all theree cytoplasms show the type II fertility spectrum (TSUNEWAKI & TSUJIMOTO 1984), and induce haploids in Salmon (TSUNEWAKI et al. 1976 ; MUKAI 1981). The allelic relationship between the three genes must be thoroughly investigated before a conclusive decision on their symbols is made. References KOBAYASHI, M. and TSUNEWAKI, K. 1980. Haploid induction and its genetic mechanism in alloplasmic common wheat. J. Hered. 71 : 9-14. MAAN, S.S. 1977. Cytoplasmic homology between Aegilops mutica Boiss. and Ae. ovata L. Euphytica 26 : 601-613. MUKAI, Y. 1981. Genetic studies on the cytoplasms in tetraploid Aegilops species. Doctor Dissert. Fac. Agr. Kyoto Univ. Japan. pp 248. MUKAI, Y. 1983. Determination of the chromosome arm carrying a male fertility-restoring gene against the cytoplasm of Ae. uniaristata in wheat. Memo. Osaka Kyoiku Univ., Ser. III, 32 : 42-53. MUKAI, Y.and TSUNEWAKI, K. 1979. Basic studies on hybrid wheat breeding. VIII. A new male sterility-fertility restoration system in common wheat utilizing the cytoplasms of Ae. kotschyi and Ae. variabilis. Theor. Appl. Genet. 54 : 153-160. PANAYOTOV, I. 1980. New cytoplasmic male sterility sources in common wheat : Their genetical and breeding consideration. Theor. Appl. Genet. 56 : 153-160. SEARS, E.R. and SEARS, L.M. 1978. The telocentric chromosomes of common wheat. Proc V Int. Wheat Genet. Symp. : 389-407. TERACHI, T., OGIHARA, Y. and TSUNEWAKI, K. 1984. The molecular basis of genetic diversity among cytoplasms of Triticum and Aegilops. III. Chloroplast genomes of the M and modified M genome-carrying species. Genetics (in press). TSUNEWAKI, K., MUKAI, Y., ENDO, T.R., TSUJI, S. and MURATA, M. 1976. Genetic diversity of the cytoplasm in Triticum and Aegilops. VI. Distribution of the haploid-inducing cytoplasm. Jpn. J. Genet. 51 : 193-200. TSUNEWAKI, K. and TSUJIMOTO, H. 1984. Genetic diversity of the cytoplasm in Triticum and Aegilops. Proc. VI Int. Wheat Genet. Symp. (in press). ZELLER, F.J. 1973. 1B/1R wheat-rye chromosome substitutions and translocations. Proc. IV Int. Wheat Genet. Symp.: 209-221. |
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