Coefficients of the logistic regression for dry matter translocation to tubers (HI, X₀ and R²) and maximum tuber growth or bulking rate (TG_max).

Where: HI is the maximum value that α reaches, X₀ is the point in thermal time (°Cd), where the maximum speed of translocation of assimilates is given, TG_max is the Maximum tuber growth or bulking rate (g m⁻² °Cd⁻¹). SE is the Standard error; R² is the determination coefficient at P<0.01 (**).