SKAGGS, DALE1*, HEATHER SWEET2, and JOHANNE BRUNET2. 1Department of Horticulture, Oregon State University, Corvallis, OR 97331; 2Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331. - The impact of plant architecture on selfing rate in Aquilegia coerulea (Ranunculaceae).
The number of flowers open on a plant can influence the level of among
flower selfing or geitonogamy. We compared selfing rate, estimated
with allozyme data from progeny array, between two populations of
Aquilegia coerulea in southwest Utah. In the Archery population
55 % of the plants had a single flower, in contrast to 21 % of the
plants in the Cedar Breaks population. As no geitonogamous selfing can
occur in single-flowered plants, we hypothesized that selfing rate
would be lower at the Archery population. This assumes that
geitonogamous selfing contributes to selfing rate in these
populations. To control for other variables that could potentially
influence selfing rate between these two populations, we measured the
level of protandry, recorded pollinator abundance, flower size and
plant density. We also bagged plants in each of these two populations
to determine the potential for autogamous selfing in these
populations. There was no difference in the multilocus estimate of
selfing rate, using PGM and MPI, for Cedar Breaks (selfing rate = was
0.22 +/- 0.08 , 41 families and 549 progenies) and Archery (selfing
rate = 0.20 +/- 0.8, 38 families and 284 progenies). At both sites,
bees did the majority of pollination. Our results suggest that plant
architecture and geitonogamy do not strongly influence selfing rate in
these two populations of A. coerulea.
Key words: Aquilegia coerulea, autogamy, geitonogamy, plant architecture, pollination, selfing rate