The expected efficiency of light utilization in plant populations as affected by different selection and competition regimes

The efficiency of light utilization for seed production by plants decreases when plants continuously growing in a dense stand are competing for light. The efficiency also decreases when the canopy structure is horizontal and closed at the top. It is concluded that competition between plants when light is limited favours the inefficient mode of growth and canopy structure. Efficient production may be expected either when light is not a limiting factor or when selection is for a maximal yield per unit area such as in crop plants. The efficiency of seed production in some crop plants may possibly be increased by selecting for a non-competitive mode of growth, and for a dense vertical and not too high canopy structure.