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Pollen dispersal and optimal outcrossing in Delphinium nelsoni


NATURAL SELECTION, in sexually reproducing plants, should often favour matings between individuals of intermediate genetic similarity. Matings between very similar individuals may lead to inbreeding depression because segregational load is revealed1,2, while matings between very dissimilar individuals may disrupt favourable gene combinations and lead to outbreeding depression3–5. Outbreeding depression in plants has been documented in crosses between species, varieties and isolated populations6–9, and reports of inbreeding depression date back at least a century10 We suggest that outbreeding depression will often occur on a much finer scale than previously recognised, especially in plants subject to restricted pollen and seed dispersal. Such plants are likely to show pronounced microgeographic genetic differentiation resulting from drift in subpopulations isolated by distance or from adaptation to local edaphic and biotic conditions11,12 Under these circumstances, a short outcrossing distance may be optimal not only because of intragenotypic effects, but also because it produces offspring sufficiently similar to the female parent to grow successfully near her, yet sufficiently genotypically diverse to maximise success of the total progeny in the face of coarse-grained temporal environmental variation13–15, frequency-dependent sibling competition16–18 or predation19–20. Here we present evidence that a short outcrossing distance is optimal for Delphinium nelsoni Greene and discuss the relationship between the optimal outcrossing distance for D. nelsoni and actual pollen dispersal by its main pollinators.

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  1. 1

    Crow, J. F. in Heterosis (ed. Gowen, J. W.) 282–297 (Iowa State College Press, Ames, 1952).

    Google Scholar 

  2. 2

    Dobzhansky, T. Genetics of the Evolutionary Process 193–197 (Columbia University Press, New York, 1970).

    Google Scholar 

  3. 3

    Darlington, C. D. & Mather, K. The Elements of Genetics 227–229 (Allen and Unwin, London, 1949).

    Google Scholar 

  4. 4

    Falconer, D. S. Introduction to Quantitative Genetics 261–263 (Longman, London, 1960).

    Google Scholar 

  5. 5

    Prakash, S. & Lewontin, R. C. Proc. Natn. Acad. Sci. U.S.A. 59, 398–405 (1968).

    ADS  CAS  Article  Google Scholar 

  6. 6

    Müller, H. The Fertilisation of Flowers 145–146 (Macmillan, London, 1883).

    Book  Google Scholar 

  7. 7

    Kruckeberg, A. R. Evolution 11, 185–211 (1957).

    Article  Google Scholar 

  8. 8

    Moll, R. H., Lonnquist, J. H., Velez Fortuno, J. & Johnson, E. C. Genetics 52, 139–144 (1965).

    CAS  PubMed  PubMed Central  Google Scholar 

  9. 9

    Hughes, K. W. & Vickery, R. K. J. Genet. 61, 235–245 (1974).

    Article  Google Scholar 

  10. 10

    Darwin, C. The Effects of Cross and Self Fertilisation in the Vegetable Kingdom (Murray, London, 1876).

    Book  Google Scholar 

  11. 11

    Jain, S. K. & Bradshaw, A. D. Heredity 20, 407–441 (1966).

    Article  Google Scholar 

  12. 12

    Schaal, B. A. Nature 252, 703 (1974).

    ADS  CAS  Article  Google Scholar 

  13. 13

    Levins, R. Evolution in Changing Environments 10–38 (Princeton University Press, Princeton, 1968).

    Google Scholar 

  14. 14

    Selander, R. K. & Kaufman, D. W. Proc. Natn. Acad. Sci. U.S.A. 70, 1875–1877 (1973).

    ADS  CAS  Article  Google Scholar 

  15. 15

    Treisman, M. J. theor. Biol. 60, 421–431 (1976).

    CAS  Article  Google Scholar 

  16. 16

    Kojima, K. & Yarbrough, K. M. Proc. natn. Acad. Sci. U.S.A. 57, 645–649 (1967).

    ADS  CAS  Article  Google Scholar 

  17. 17

    Seaton, A. P. C. & Antonovics, J. Heredity 22, 19–34 (1967).

    CAS  Article  Google Scholar 

  18. 18

    Allard, R. W. & Adams, J. Am. Nat. 103, 621–645 (1969).

    Article  Google Scholar 

  19. 19

    Clarke, B. in Taxonomy and Geography (ed Nichols, D.) 47–70 (Systematics Association, Oxford, 1962).

    Google Scholar 

  20. 20

    Dolinger, P. M., Ehrlich, P. R., Fitch, W. L. & Breedlove, D. E. Oecologia 13, 191–204 (1973).

    ADS  Article  Google Scholar 

  21. 21

    Waser, N. M. Ecology (in the press).

  22. 22

    Sokal, R. R. & Rohlf, F. J. Biometry 621–624 (Freeman, San Francisco, 1969).

    Google Scholar 

  23. 23

    Epling, C. & Lewis, H. Evolution 6, 253–267 (1952).

    Article  Google Scholar 

  24. 24

    Pyke, G. H. Oecologia 36, 281–293 (1978).

    ADS  Article  Google Scholar 

  25. 25

    Brink, R. A. Heterosis (ed. Gowen, J. W.) 81–97 (Iowa State College Press, Ames, 1952).

    Google Scholar 

  26. 26

    Heslop-Harrsion, J., Heslop-Harrison, Y. & Barber, J. Proc. R. Soc. B188, 287–297 (1975).

    ADS  Article  Google Scholar 

  27. 27

    Hogenboom, N. G. Proc. R. Soc. B188, 361–375 (1975).

    ADS  Article  Google Scholar 

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PRICE, M., WASER, N. Pollen dispersal and optimal outcrossing in Delphinium nelsoni. Nature 277, 294–297 (1979).

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