| Conclusion An investigation was carried out on Rf genes of Triticum macha var. subletschchumicum against timopheevi cytoplasm and these genes were transfered into a common wheat cultivar. Since T. macha has Ch1 gene for hybrid chlorosis, and most of common wheat cultivars have Ch2, their F1 hybrids become lethal due to chlorosis. Therefore, T. macha was first crossed to NIG-2 which has neither Ch1 nor Ch2 gene. The F1 plants were crossed to (timopheevi)-Chinese Spring to select the plants having the Rf genes of T. macha, but free from the Ch1 gene. From these crosses, 13 chlorotic, four sterile and 19 fertile plants were segregated, which suggested that T. macha has two dominant fertility- restoring genes. From these fertile plants, four lines were selected, and their progenies were tested for the segregation of fertility. The data indicated that line #2 has two Rf genes, the other three have only one gene for fertility restoration. The plant which showed highest fertility in line #2 was selfed and backcrossed to Chinese Spring. The line #2-S1 (F3) is homozygous for the Rf genes and most of them showed more than 80% of selfed seed fertility. While, the B1F1 plants showed wide range in selfed seed fertility like in F2. These Rf genes of T. macha may be useful for breeding restorer lines against tiompheevi cytoplasm. Acknowledgement The author wishes to express his appreciation to Dr. K. TSUNEWAKI who kindly provided the strain NIG-2 used in the present investigation and read this manuscript critically. The author also thanks to Professor M. KAMANOI and Dr. T. SASAKUMA for their kind advices, discussions and supports. Literature Cited FUJIGAKI, J. and K. TSUNEWAKI (1976). Basic studies on hybrid wheat breeding. VII. Characteristics of the male sterile lines of common wheat cultivars. Japan. J. Breed. 26: 179-186. HERMSEN, J.G. The and J. WANINGE (1972). Attempts to localize the gene Ch1 for hybrid chlorosis in wheat. Euphytica 21: 204-208. KIHARA, H. (1951). Substitution of nucleus and its effect on genome manifestations. Cytologia 16: 177-193. KIHARA, H and K. TSUNEWAKI (1966). Basic studies on hybrid wheat breeding, carried out at the National Institute of Genetics. Seiken Ziho 18: 55-63. MILLER, J.F., J.W. SCHMIDT and U.A. JOHNSON (1974). Inheritance of genes controlling male-fertility restoration in the wheat cultivar Primepi. Crop Sci. 14: 437-438. TSUNEWAKI, K. (1975). Monosomic analysis of a chlorosis gene Ch1 in common wheat. Japan. J. Genet. 50: 151-154. TSUNEWAKI, K.(1975). Production of the single gene testers for necrosis and chlorosis in wheat. Japan. J. Breed. 25 Sppl. 1: 130-131. (in Japanese) TSUNEWAKI, K. and H. Kihara (1961). F1 monosomic analysis of Triticum macha. Wheat Inf. Serv. 12: 1-3. |
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