Fig. 1. Evolution of relative grain dry weight on a thermal time scale for Q. Palomar cultivar from different experiments done at the Facultad de Agronomía de la Universidad de Buenos Aires (six in 1995, one in 1996, and four in 1997). Data was fitted to a model with two linear equations (r² = 0.81, n = 108). Physiological maturity occurred at the interception of both lines, i.e., 440°C-day (SE = 16.2°C-day). Base temperature that maximized r² was T_b = 5.5°C.