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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Stevens, J., Bougourd, S. Inbreeding depression and the outcrossing rate in natural populations of Allium schoenoprasum L. (wild chives). Heredity 60, 257–261 (1988). https://doi.org/10.1038/hdy.1988.40
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DOI: https://doi.org/10.1038/hdy.1988.40
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