Skip to main content

Table 3 Linear (β) and quadratic (γ) selection differentials for phenology, biomass, and ecophysiology traits

From: Phenotypic plasticity of natural Populus trichocarpa populations in response to temporally environmental change in a common garden

Trait Year β γ
Bud set 2009 0.255*** − 0.043***
2010 0.386*** −0.027
Canopy duration 2009 0.121*** −0.032
2010 0.240*** −0.042
Growth period 2009 0.187*** −0.036*
2010 0.347*** −0.102***
Leaf drop 2009 0.232*** −0.023
2010 0.342*** 0.201***
Post-bud set period 2009 −0.162*** −0.047**
2010 −0.316*** −0.108***
Height: diameter 2009 0.082*** −0.060**
2010 0.008*** −0.073*
Active growth rate 2009 0.293*** −0.032**
2010 0.399*** −0.023
Amax 2009 −0.077*** −0.024
2010 0.002 −0.092
Amax/mass 2009 −0.053** −0.042*
2010 −0.054 −0.038
C: N 2009 − 0.025 0.027
2010 0.045 −0.065
leaf 2009 −0.054** −0.050
2010 −0.110*** −0.037
δ15N 2009 −0.002 −0.019
2010 −0.028 −0.038
gs 2009 −0.093*** −0.035
2010 −0.089** −0.090*
LMAsummer 2009 −0.037* −0.018
2010 0.027 −0.051
Narea 2009 0.006 0.010
2010 0.007 −0.046
Nmass 2009 0.031 0.010
2010 −0.059 −0.062
NUE 2009 −0.082*** −0.006
2010 −0.011 −0.047
WUE 2009 0.029* −0.007
2010 0.097*** −0.093**
  1. Significance: * P < 0.05, ** P < 0.01, *** P < 0.001
  2. The signs and magnitudes indicate the direction and strength of the linear (β) or non-linear (γ) selection on each trait in either year. Significant F-tests indicates nonzero selection differentials (Additional file 1: Table S4) on a trait in a given year. The selection differential describes both direct and indirect selection on each trait. It equals to the regression coefficient of relative fitness onto standardized trait values after controlling the effect of any unmeasured traits on fitness by including a random intercept term, ‘Genetics’ (i.e., average Euclidean genetic distance using genetic marker data). For quadratic selection, a negative, significant value of γ indicates stabilizing selection, while a positive value is evidence for disruptive selection (tests detailed in Additional file 1: Table S5). Both selection analyses were visualized in Additional file 1: Figures S9 and S10