On the Nature of Incompatibility Alleles in Taraxacum elatum×T. longe-appendiculatum
Self-incompatibility Studies in Taraxacum I
1956 Volume 69 Issue 822 Pages 592-597
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1956 Volume 69 Issue 822 Pages 592-597
1. Crosses were made between 17 self-incompatible plants belonging to five diploid species of Taraxacum. The existence of a large number of incompatibility alleles in genus Taraxacum is suggested by the occurrence of few cross-incompatible combinations (Table 1).
2. Progenies of a cross between two self-incompatible species, T. elatum Kitamura and T. longe-appendiculatum Nakai were genetically analysed and found to consist of four intra-incompatible classes (Table 2). The compatibilities and incompatibilities among these four classes and two original parental plants can be explained by a hexagonal diagram on the assumption that a single series of fouroppositional multiple alleles is responsible (Fig. 4).
3. Pollen behavior is sporophytically controlled. All the pollen grains from one Plant act alike and depend on the genotype of its parental sporophyte. In this experiment S4 is recessive to each of the other three alleles. S1, S2 and S3 are “Strong” and dominant over S4, but each strong allele exhibits equal dominance values in the presence of the other. Both S1 and S2 pollen grains from a mother cell with S1 S2 alleles behave equally as S1 S2. Therefore, plants having one strong allele in common are cross-incompatible.
4. Dominance is not expressed in the pistil.
5. The self-incompatibility system found in Taraxacum is of the same type as that described for Crepis-Parthenium.
