FIGURE 3.
Relationships between annual precipitation and annual soil moisture deficit and the genetic population means of ecophysiological traits under water-restricted conditions: a,b) stomatal conductance (gs); c,d) carbon isotope composition (δ13C ‰). Soil moisture deficit is defined as potential evapotranspiration minus precipitation. In all cases, the solid line depicts the best quadratic regression fit between variables, and dashed lines are its 95% confidence intervals. Only data for B. hybridum allotetraploids are depicted (red triangles).