SELECTING FOR FLORAL CHARACTER ASSOCIATIONS IN WILD RADISH, RAPHANUS-SATIVUS L

ESS models of reproductive allocation have been used extensively to ex plain patterns of floral diversity in angiosperms. These theoretical e xplorations assume that proportional allocation to pollen, ovules, and seeds, as well as to secondary features such as showy petals and nect ar rewards, can evolve independently within the limits set by total re source 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 an d nectar production, but not with ovule or seed number per flower. The se phenotypic associations may reflect selection, environmental correl ation, and/or genetic constraint. By exerting selection on the petal s ize:pollen number ratio over two generations, we eliminated the positi ve correlation between petal size and pollen production, with both cha racters showing significant change after a single selection episode. O nce 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 natur e may be maintained by selection for effective reproductive phenotypes .