Abstract
Populations of the tristylous, self-compatible diploid Eichhornia paniculata (Spreng.) Solms. (Pontederiaceae) display wide variation in floral traits likely to influence the mating system. Progeny tests of open-pollinated plants collected from two populations in N.E. Brazil with contrasting structures (trimorphic, dimorphic) were used to investigate mating patterns. The two loci that govern the inheritance of style length were used as marker genes. A model that measures the magnitude of disassortative mating was developed using the progeny test data. Since the model does not distinguish between selling and assortative mating, outcrossing estimates are likely to be underestimated. Using the model it was shown that the mating patterns of the two populations were strikingly different. In the tristylous population a high level of disassortative mating was estimated (t = 0·903) with no significant differences among the floral morphs. In the dimorphic population (L, M) the rate of disassortative mating of the long-styled morph was t = 0·657, whereas all matings in the mid-styled morph were either selfed or assortative. Selfing in the mid-styled morph is due to alteration of the position of short-level stamens resulting in automatic self-pollination. The consequence of this mating asymmetry on the dynamics of selection at loci controlling floral trimorphism is discussed.
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Barrett, S., Brown, A. & Shore, J. Disassortative mating in tristylous Eichhornia paniculata (Pontederiaceae). Heredity 58, 49–55 (1987). https://doi.org/10.1038/hdy.1987.7
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DOI: https://doi.org/10.1038/hdy.1987.7
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