XVI International Botanical Congess

The identification and analysis of quantitative trait loci (QTLs) allows one to study the genetics of adaptive differences between interfertile taxa. We are analyzing the genetic basis of floral differences between outcrossing Mimulus guttatus and selfing M. nasutus in order to determine whether genes of large effect contribute to the extreme floral differences between these species. This goal is being accomplished through the mapping of floral QTLs in an F2 population using a high-resolution microsatellite and AFLP linkage map of the Mimulus genome. While the analysis of genetic basis of differences in floral morphology is intrinsically interesting, we also study these traits because we believe they relate to ecological differences between the species in the wild. To this end, we are introgressing the M. nasutus alleles for QTLs affecting floral traits into the M. guttatus genetic background. These introgression lines will then be used in field experiments to test the effects of the different alleles at QTLs on selfing rate, attractiveness to pollinators, and components of fitness through male and female function.