Levels of genetic variation and covariation for Mimulus (Scrophulariaceae) floral traits

In each of two populations of outcrossing Mimulus guttatus and selfing M. micranthus we quantified genetic variation for floral traits which previously were shown to be associated with mating system evolution in this genus at both the population and species levels. Both broad- and narrow-sense heritabilities and genetic correlations were measured in greenhouse experiments. For one population of M. guttatus , we investigated and found significant among family variation for autogamous seed-set in a pollinator-free environment, and this was weakly associated with stigma-anther separation. We observed intermediate to high levels of broad- and narrow-sense heritabilities for all traits, but genetic variation was consistently lower in the selfing species. Although characters correlated to stigma-anther separation or to day of first flower varied between populations and between taxa, there were consistently strong positive genetic correlations among traits associated with floral size.