Abstract
Incipient incompatibility barriers often are the incidental by-products of divergent evolution. Accordingly, one expects pollen from outside of a population to be less successful than pollen from the same population or to be similar to it. Contrary to expectation, we find that in the predominantly self-fertilising Phlox cuspidata, alien pollen typically is at an advantage. We crossed greenhouse grown plants with pollen from their own populations and pollen from other populations, and determined the germination percentage of pollen grains on stigmas. Alien pollen had higher germination rates in 13 of the 14 populations, and for 10 populations the differences were statistically significant. Over all populations, the mean germination was 27·1 per cent for alien pollen versus 20·8 per cent for local pollen, a statistically significant difference. There was no relationship between the germination of alien pollen and the distance between pollen source and recipient.
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Levin, D., Clay, K. Extraneous pollen advantage in Phlox cuspidata. Heredity 54, 145–148 (1985). https://doi.org/10.1038/hdy.1985.19
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DOI: https://doi.org/10.1038/hdy.1985.19
