Fig. 8. Relationship between oil-corrected grain yield and the time elapsed between full anthesis and the moment when leaf area index falls to 50% of that at anthesis (an estimator of canopy stay green) for 9 sunflower hybrids grown in December (S2) sowing date at Venado Tuerto during 1996-1997 and 1998-1999. **Significant at P = 0.01.