Fig. 3. Standard germination of seed lots from hybrids B and C harvested at different developmental stages in 1999 following exposure to five freezing treatments: (1) unfrozen control, exposure to –6°C for 4 or 7 h, or exposure to –11°C for 4 or 7 h. Error bars = ± SEM. Physiological maturity occurred at 366 and 304 g kg^–1 seed moisture content, for hybrids B and C, respectively.