| Chromosomal locations of genes controlling the seed
fertility of Chinese Spring against to the alien cytoplasms M. SASAKI., N. NAKATA and Y. YASUMURO Faculty of Agriculture, Tottori University, Tottori 680 Ditelocentric lines of Chinese Spring (CS) developed by Dr. E.R. SEARS are being introduced into certain cytoplasms of Aegilops and Secale (SASAKI et al. 1977, 1978). From the results obtained on the pollen and selfed seed fertilities of ditelocentrics with each of the Ae. ovata, Ae. speltoides, Ae. squarrosa and Ae. variabilis cytoplasms, it is induced that some major and a number of modifier genes locating on certain chromosome arms are controlling the fertility of CS against these alien cytoplasms. Those are summarized in Table 1. Each of the following chromosome arms carry a major gene(s) for the fertility of CS: Chromosome arms 5DS and 1BS against to the cytoplasm of Ae. ovata; 7BL to that of Ae. speltoides; 1DL to that of Ae. squarrosa. A number of modifier genes for the fertility were also located: Five on each of the chromosome arms, 2BS, 3AL, 3BS, 4DS and 7BS, to the cytoplasm of Ae. ovata; six (2AL, 2BS, 4Abeta, 4DS, 6BL, 7AS) to that of Ae. speltoides; four (1BS, 1BL, 2BS, 4BS) to that of Ae. variabilis. As seen in Table, the Rfo1 gene located on chromosome arm 5DS was active to the Ae. ovata cytoplasm but ineffective to the original, Ae. speltoides and Ae. variabilis cytoplasms whereas the Rfs1 gene on 7BL acting to the Ae. speltoides cytoplasm was not effective to the original, Ae. squarrosa and Ae. variabilis cytoplasms. Such a nucleo-cytoplasmic interaction on the gene expression for the fertility could be used for hybrid wheat breeding systems by searching an appropriate alien cytoplasm where ms mutants found in the original cytoplasm would become fertile. All gene symbols used here are tentative. |