Gender variation, partial male sterility and labile sex expression in gynodioecious Plantago coronopus

Authors

  • HANS P. KOELEWIJN,

    1. Netherlands Institute of Ecology, Department of Plant Population Biology, Boterhoeksestraat 22, PO Box 40, 6666 ZG Heteren, The Netherlands
    2. Department of Genetics, University of Groningen, The Netherlands
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    • *

      Current address: University of Oulu, Department of Genetics, SF-90570 Oulu, Finland.

  • JOS M. M. VAN DAMME

    1. Netherlands Institute of Ecology, Department of Plant Population Biology, Boterhoeksestraat 22, PO Box 40, 6666 ZG Heteren, The Netherlands
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SUMMARY

Gynodioecy is 8 breeding system consisting of male, steriles (MS, females) and hermaphrodites (H). There is however within such systems a third, often neglected, class of partially male sterile plants (PMS), i.e. plants with an intermediate sex expression, In natural populations of Plantago coronopus partially male sterile individuals were us common as male steriles (frequencies in the range 1·7–36·8%). These PMS plants constitute a continuous series, linking complete male sterility and hermaphroditism. We discovered that temperature influenced sex expression and the degree of male sterility of PMS individuals, but not of MS and H individuals. Thus, at higher temperatures PMS individuals became more male sterile. Difference in cytoplasmic background of the individuals did nut influence their response to temperature. It is argued that partial male sterility is a normal feature of gynodioecious species and not an abnormality.

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