Consequences of Low Mate Availability in the Rare Self‐Incompatible Species Brassica insularis | Consequences of Low Mate Availability in the Rare Self‐Incompatible Species Brassica insularis
2008
GLÉMIN, SYLVAIN | Petit, Christophe | MAURICE, SANDRINE | MIGNOT, AGNÈS
Self‐incompatibility systems prevent self‐fertilization in angiosperms. Although numerous S alleles are usually maintained by negative frequency‐dependent selection, the number of S alleles can be low in small populations, which limits mate availability and reduces fecundity in endangered populations of self‐incompatible plants. Despite the increasing evidence of the negative effect of self‐incompatibility in small populations, the direct link between the number and the distribution of S alleles and their reproductive consequences has been rarely reported. Brassica insularis is a rare self‐incompatible species with medium to very small populations. Results of a previous study showed that the smallest population has very few S alleles. We investigated whether reduced mate availability affects reproduction in this species. We compared the pollination success and the fruit set in 4 populations differing in population size and number of S alleles. Our results suggest that reproduction may be negatively affected by the low S‐allele diversity in the smallest population. Nevertheless, other populations also had reduced fruit set that could not be attributed to self‐incompatibility alone.
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