Summary
Plants of Senecio vulgaris homozygous for the rayed gene (RR) show markedly slower growth characteristics than unrayed plants (rr) from the same British population; the former are, however, very similar in growth to an unrayed population from a Mediterranean district of Yugoslavia (YY). Studies of genetic interaction with r, of plasticity, and of taxonomic characters suggest that slow growth has arisen independently in RR and YY. It seems that the rayed allele R is part of a linked gene complex, and it is suggested that this has resulted from introgression with the related Mediterranean species S. squalidus, which is now widespread in Britain.
Although it seems likely that RR and YY are functionally annual, perhaps in response to the hot summer Mediterranean rest-period experienced by YY and native S. squalidus, R may be able to coexist with the more rapidly reproducing rr genotype in Britain through a superior reproductive capacity in competitive situations.
Considerable variation is noted in the ligule length in the Rr heterozygote, in which R is incompletely dominant, and it is suggested that although the artificial selection for dominance in this attribute might be readily demonstrated, there is little evidence of selective pressures leading to dominance in the wild. Indeed a stable polymorphism for R and r seems to exist at the present time.
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Allen, D E. 1967. Taxonomy and nomenclature of the radiate variants Senecto vulgaris L. Watsonia, 6 (5), 280–282.
Crisp, P, and Jones, B M G. 1970. Senecio squalidus L., S. vulgaris L. and S. cambrensis Rosser. Watsonia, 8, 47–48.
Druce, G C. 1886. Flora of Oxfordshire. Oxford.
Federova, A A. 1969. Chromosome Numbers of Flowering Plants. V. L. Komerov Botanical Institute, Leningrad.
Ford, E B. 1940. Genetic research in the Lepidoptera. Ann Eugen, Lond, 10, 227–252.
Haskell, G. 1953. Adaptation and the breeding system of groundsel. Genetica, 26, 468–484.
Hull, P. 1974. Self-fertilisation and the distribution of the radiate form of Senecio vulgaris L. in Central Scotland. Watsonia, 10, 69–75.
Perring, R H, and Sell, P D. 1968. Critical Supplement to the Atlas of the British Flora. London.
Perring, R H, and Walters, S M. 1962. Atlas of the British Flora. London.
Popay, A I, and Roberts, E H. 1970. Factors involved in the dormancy and germination of Capsella bursa-pastoris (L.) Medic, and Senecio vulgaris L. J Ecol, 58, 103–122.
Trow, A H. 1912. On the inheritance of certain characters of the common groundsel. J Genet, 2, 239.
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Richards, A. The inheritance and behaviour of the rayed gene complex in Senecio vulgaris. Heredity 34, 95–104 (1975). https://doi.org/10.1038/hdy.1975.9
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DOI: https://doi.org/10.1038/hdy.1975.9
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