Fig. 3. Simulated soybean seed harvest index in response to varying the filling period duration (beginning seed, R5, to physiological maturity) at Ames, IA, for 1980–1996 rainfed weather. Treatments include standard N mobilization and 20% slower N mobilization (both with 11 adequate rainfall years) and standard N mobilization (with 6 drought-prone years). Horizontal bar represents feasible genetic range for filling period duration. Reprinted from Boote et al. (2001) with permission.