Among-Population Variation of Outcrossing Rate in the Winter Annual Plant Collinsia verna
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Authors
Benson, Michael J.
Issue Date
2007-04-27
Type
Language
en_US
Keywords
Alternative Title
Abstract
Many plants utilize a mixed mating system whereby reproduction may occur by self-fertilization
(selfing) and by cross-pollination (outcrossing). In population genetics, knowledge of the mating
system is very important, because mating patterns influence the amount and the distribution of
genetic variability of populations (i.e. the mating structure) and consequently evolutionary
processes in these populations. The most common descriptor of the mating structure of plant
populations is the estimated outcrossing rate (t), the proportion of seeds produced by
outcrossing. This study quantifies the outcrossing rates in 11 natural populations of the mixed
mating, winter annual plant Collinsia verna from across its entire geographic range, and
compares the results to a previous study that quantified outcrossing rates in populations of C.
verna from only Michigan and Illinois. It was hypothesized that because more environmental
variation exists over a larger geographic range, there would be more variation in outcrossing
rates over the larger geographic range. Outcrossing rates were quantified by genotyping at
least five offspring from 32 plants in 11 populations spanning the geographic range of C. verna.
Outcrossing rates varied markedly from t = 0.59 – 0.86 across the sampled populations, but
there was no significant variation between studies. It is thought that this among-population
variation in outcrossing rates is due to among-population variation in factors that have been
shown to affect outcrossing rates in other species, such as types of pollinators, pollinator
availability, population size, plant density, herkogamy, protandry, and floral display size.
However, further studies directed toward quantifying these factors at different sites are needed
in order to more fully understand the evolutionary processes on the mixed mating system
employed by C. verna.
Description
1 broadside : ill.
Citation
Publisher
Kalamazoo College