Abstract Detail



Sexual selection in flowering plants: traits, processes, and estimation

Marshall, Diane [1].

Sexual selection in wild radish: intensity of pollen competition, seed paternity, and offspring characteristics.

Sexual selection seems likely in plants because far more pollen grains are produced than ovules. However, clear consensus on how often sexual selection plays an important evolutionary role has been difficult to achieve. One problem has been in the interpretation of disparate results from experiments where offspring vigor was measured after varying the intensity of pollen competition and studies that evaluated seed paternity after mixed pollination. I addressed this question by studying both seed paternity and offspring characteristics after performing mixed donor pollen loads of varying size. Seed paternity differed among pollen donors, but was unaffected by pollen load size.  Among progeny of these crosses grown in an experimental garden, effects of pollen donor identity were significant on aboveground biomass and a variety of reproductive characters. While progeny of the smallest pollen loads tended to be smaller and reproduce less, these differences did not even approach significance. However, in a focused, greenhouse stud, plants from small and large pollen loads differed in pollen production with progeny from small pollen loads producing more pollen grains per flower than progeny from large pollen loads.  Overall, there was considerable evidence that mate choice is important in determining seed paternity. Given differences in success of plants sired by different pollen donors, selection should favor mate choice. There were also indications that the mating conditions of low pollen load size could select for different characteristics than the mating conditions of higher pollen load sizes.


1 - University Of New Mexico, Biology, Dept Of Biology, MSC03 2020, 1 University Of New Mexico, Albuquerque, NM, 87131, United States

Keywords:
Sexual selection
wild radish
pollen load size.

Presentation Type: Colloquium Presentations
Number: 0005
Abstract ID:568
Candidate for Awards:None


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