Climate change will extend growing seasons. Plants that bloom at the date that takes best advantage of the longer season may produce more seeds and thus make disproportionate genetic contributions to the next generation. In other words, selection on flowering time is expected to act through female function. But most plants are hermaphrodites, and so also contribute genes to the next generation by exporting pollen to fertilize the seeds on other plants. Recent theoretical models suggest that the optimal flowering time for pollen export may not be the same as that for seed production. Thus, flowering time may evolve toward a compromise date. To test this mode we will measure selection through female and male function in field mustard, Brassica rapa. Female success will be measured by counting seed production on sample plants. Estimating male success is more difficult, since individual pollen grains cannot be tracked. Instead, produced seeds will be genetically fingerprinted, along with all potential fathers, and paternity analysis performed. With the resulting data we will determine whether the plants that were the most successful “fathers” were those that bloomed early-,mid- or late-season.
Emily Austen, Ecology and Evolutionary Biology, University of Toronto
Bergita Petro, Ecology and Evolutionary Biology, University of Toronto
Alex Levitt, Bergita Petro, Ecology and Evolutionary Biology, University of Toronto