| Male fertility restoration against various alien cytoplasms.
I. Comparison between the restoration abilities of three groups of lines I. PANAYOTOV, D. K. GOTSOV* and K.GOTSOV Institute for Wheat and Sunflower, Tolbuhin, Bulgaria Various sources of male sterility-inducing cytoplasms with origin from different Triticum and Aegilops species are available at present, but, nevertheless, the hybrid wheat breeding programmes on world-wide scale make use mainly of the cytoplasm of T. timopheevi (WILSON & ROSS 1962). By far, many authors had pointed out the complications that might arise from relying on a single source of male sterility. It is highly desirable then, to broaden the genetic basis of the male sterility-fertility restoration system in wheat by inclusion of other CMS-sources. The results presented in this paper are part of a study on the phenotypic effects and male fertility-restoration systems of various alien cytoplasms. Materials and Methods Two common wheat cultivars, Aurora and Roussaka, were used as recurrent pollen parents for the production of the male sterile (MS) lines. The following Triticum and Aegilops species served as donors of the alien cytoplasms : Aegilops triuncialis, Ae. mutica, Ae. comosa, Ae. speltoides and Triticum dicoccoides var. spontaneovillosum. They exert neutral or slightly negative effect on the wheat phenotype (PANAYOTOV 1980) and as such, they might be included in hybrid wheat breeding as alternative sources of male sterility. The MS lines of Aurora and Roussalka with the cytoplasm of T. timopheevi were included in the experiment for comparison. The alloplasmic lines were produced and maintained by one of the authors (Panayotov). At the beginning of the study they were in BC4-BC9 generation. In an attempt to discover male fertility-restoring genes against the above mentioned cytoplasms we studied three groups of lines. First, we surveyed a group of 20 common wheat cultivars (or advanced true-bred lines). The other two groups consisted of restorers of male fertility, whose Rf-genes orginated from various Triticum and Aegilops species. Crosses were made between the male sterile lines as female parents and the common wheat cultivars or the R-lines as pollen donors. The F1 generation was grown either in the greenhouse or in the field (depending on the type of the R-line) and 2 to 3 spikes per plant were bagged before anthesis. The level of male fertility restoration was estimated as percentage of the seeds set in the 1 st and 2nd florets of each spikelet. |
| * Present address : Institute of Genetics, 1113 Sofia, Bulgaria |
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