Heritability of floral traits for the perennial wild flower penstemon centranthifo/ius (Scrophulariaceae): Clones and crosses

Floral and reproductive traits frequently influence pollinator behaviour and plant reproductive success and are therefore thought to be under selection. However, for wild plant populations there is little information on the amount of genetic variation for such traits. We estimated broad- and narrow-sense heritability of floral and reproductive traits for two populations of the perennial wildflower Penstemon centranthifolius, using a paternal half-sib crossing design in one case, and clonal propagation of ramets from different genets in the other. In both designs, most traits were significantly heritable, including nectar production, corolla length and width, inflorescence length and total flower production. Flowering date was significantly heritable for the crosses, but not for the clones, while nectar sugar concentration was not significantly heritable in either design. Genetic correlations were in some cases strong, and in some cases differed greatly from the corresponding phenotypic correlations. These results indicate that P. centranthifolius harbours a large reservoir of genetic variance which could support an evolutionary response to phenotypic selection.