There is mounting evidence that plants are responding to anthropogenic climate change with shifts in flowering phenologies. We conducted a three-generation artificial selection experiment on flowering time in Campanulastrum americanum, an autotetraploid herb, to determine the potential for adaptive evolution of this trait as well as possible costs associated with enhanced or delayed flowering. Divergent selection for earlier and later flowering resulted in a 25-day difference in flowering time. Experiment-wide heritability was 0.31 and 0.23 for the initiation of flowering in early and late lines, respectively. Selection for earlier flowering resulted in significant correlated responses in other traits including smaller size, fewer branches, smaller floral displays, longer fruit maturation times, fewer seeds per fruit and slower seed germination. Results suggest that although flowering time shows the potential to adapt to a changing climate, phenological shifts may be associated with reduced plant fitness possibly hindering evolutionary change.
Bibliographical noteFunding Information:
We thank V Fuentes, L Guarinello, R Gittman, A Smith and H Truong for assistance in the greenhouse; W Crannage for plant care; M Geber for sharing a literature summary; NSF (DEB-9974126, DEB-0316298) and a UVA-FEST award to LFG for financial support.
- Artificial selection
- Campanulastrum americanum
- Correlated response
- Flowering time
- Realized heritability