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Inbreeding depression and the outcrossing rate in natural populations of Allium schoenoprasum L. (wild chives)

Heredity volume 60, pages 257261 (1988) | Download Citation

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Abstract

The level of inbreeding depression has been measured at four independent stages of the life cycle (parental seed fecundity, seed viability, seedling survival and seedling growth rate) using wild-collected parental plants from seven natural populations of Allium schoenoprasum. At each stage, progenies produced by self-fertilisation were significantly less fit than progenies produced by cross-fertilisation, and the overall inbreeding depression was severe (0·718). This suggests that a high level of cross-fertilisation usually occurs in natural populations, despite the fact that A. schoenoprasum is a clonal, self-compatible, hermaphrodite plant, with apparently ample opportunities for geitonogamous selfing.

Using a white flower colour marker, the minimum outcrossing rate in a natural population has been estimated as 0·91. However, this is almost certainly an over-estimate due to the unequal viabilities of cross and self zygotes. An adjusted estimate of tmin = 0·80 is derived which takes account of the lower survival rate of self zygotes

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Author notes

    • J P Stevens

    Present address: Department of Botany and Microbiology, University College of Swansea, Singleton Park, Swansea SA2 8PP, UK.

Affiliations

  1. Department of Biology, University of York, York YO1 5DD, UK

    • J P Stevens
    •  & S M Bougourd

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DOI

https://doi.org/10.1038/hdy.1988.40

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