Fig. 1. (A) Maximum fraction of incident photosynthetic active radiation intercepted (fPAR) by crops cultivated in wide rows (WR) vs. those in narrow rows (NR); and (B) red:far-red ratio (R/FR) reaching the ear leaf layer and the lowermost green leaf layer of crops in WR vs. those in NR. Data points represent the mean values of each treatment (plant population x row spacing x hybrid) in all experiments (Fig. 1A), and in E₁ and E₂ (Fig. 1B). Black symbols, hybrids of small kernel weight; gray symbols, hybrids of large kernel weight. The solid lines indicate the model fitted to the data set. The dashed line indicates the 1:1 relationship between variables.