Further experiments on photosynthesis and translocation in wheat

A model is deveolped relating photosynthesis taking place in successive layers of the canopy of a wheat crop to the intensity of the radiation incident on the crop, the elevation of the sun, and to the angle to the horizontal and photosynthetic area of ears, leaves and leaf sheaths. The validity of the model is tested by comparing the rate of photosynthesis, pattern of translocation and solid geometry of a semi-dwarff wheat (TL 365a/25) with those of a variety of conventional height (Cappelle-Deprez). The model gives realistic estimates of crop yield and indicates that the greater yield of the semi-dwarf selection is caused by faster photosynthesis, despite less photosynthetic surfaces of ears and leaves. It also indicates that selection for erect leaves may lead to further increases in yield.