Figure 4.

Proportion of leaves of a canopy orientated perpendicular to the row in maize hybrids DK696 and experimental hybrid 980 (Exp980) as affected by plant rectangularity (distance between rows/distance within rows). Leaf orientation was measured at tasseling in 15 plants of each condition. A leaf was classified as perpendicular to the row when its azimuthal angle with the row line (0°–180°) was comprised within either the 67° 30′ to 112° 30′ or 247°30′ to 292° 30′ intervals (Girardin and Tollenaar, 1994). Plant population density (plants m⁻²) and the ratio between the longest and the shortest distance between two plants are indicated next to the symbols. Regression lines were fitted to each hybrid data. DK696 data are redrawn after Maddonni et al. (2001a).