Selecting for floral character associations in wild radish, Raphanus sativus L.
Article first published online: 11 DEC 2002
Journal of Evolutionary Biology
Volume 7, Issue 3, pages 271–285, May 1994
How to Cite
Stanton, M. and Young, H. J. (1994), Selecting for floral character associations in wild radish, Raphanus sativus L. Journal of Evolutionary Biology, 7: 271–285. doi: 10.1046/j.1420-9101.1994.7030271.x
- Issue published online: 11 DEC 2002
- Article first published online: 11 DEC 2002
- Received 9 June 1992; accepted 26 October 1993.
- Cited By
- Reproductive allocation;
- floral evolution;
- genetic constraints;
- pollen production;
- petal size.
ESS models of reproductive allocation have been used extensively to explain patterns of floral diversity in angiosperms. These theoretical explorations assume that proportional allocation to pollen, ovules, and seeds, as well as to secondary features such as showy petals and nectar rewards, can evolve independently within the limits set by total resource availability. In populations of California wild radish, we have shown previously that petal size, a strong determinant of visitation by honey bee pollinators, is positively correlated with both pollen and nectar production, but not with ovule or seed number per flower. These phenotypic associations may reflect selection, environmental correlation, and/or genetic constraint. By exerting selection on the petal size : pollen number ratio over two generations, we eliminated the positive correlation between petal size and pollen production, with both characters showing significant change after a single selection episode. Once these two floral traits became uncoupled, nectar sugar production was significantly correlated only with petal size. Our results suggest that natural selection could readily alter reproductive allocation in these flowers, and that the phenotypic correlations observed in nature may be maintained by selection for effective reproductive phenotypes.