Phenotypic plasticity
Three different parameters were used to quantify phenotypic plasticity
in the MAGIC-MET design. For each trait, the slope and VAR from the
Finlay-Wilkinson regression model and the genotypic sensitivity to the
most important environmental covariate (SCv) from the factorial
regression model were extracted. A large genetic variability was
observed for plasticity of all traits (Supplemental Figure 5 and
Supplemental Figure 6). Besides, significant correlations were found
between the mean phenotypes and plasticity parameters (Figure 2) for
most of the traits. The best average-performing genotypes were usually
the most responsive to environmental variation as highlighted by the
positive correlation between the genotypic means and slope from the
Finlay-Wilkinson regression model. The majority of the MAGIC lines
responded in the same direction to the environmental quality and only a
few genotypes (none in the case of height) showed negative reaction
norms; however, more divergent shapes of reaction norms were observed
from the factorial regression model (Supplemental Figure 5).