Quantitative genetics of developmental stability in flower traits of Solanum rostratum

Within-individual variation in floral organs is an important phenotypic
component that can influence fitness in flowering plants. While the
genetic basis of this variation has been previously studied, the structure
of its G-matrix and evolutionary potential remained unexplored. We
characterize the G-matrix of within-individual floral organ variation
in Solanum rostratum and evaluate potential evolutionary
constraints. Within-individual variation was estimated as residual
deviations from a repeatability model. Using an animal model on
mean-standardized phenotypic data, we quantified narrow-sense
heritabilities, conditional and unconditional evolvabilities, and genetic
correlations for floral organ sizes and their within-individual variation.
We found that within-individual variation exhibited higher conditional and
unconditional evolvabilities compared to floral organ sizes.
Evolvabilities of floral organ sizes were constrained by both additive
genetic variance and genetic correlations. In contrast, within-individual
variation was primarily limited by additive genetic variance, as only a
few genetic correlations were detected for this component. Our study
provides the first analysis of how genetic correlations constrain the
evolutionary potential of within-individual variation, a metric reflecting
developmental stability in floral phenotypes.