Reducing Inflorescence Formation by Shading Individual Sultana Buds

For four seasons, individual buds developing on sultana vines in the field were shaded with a number of materials during the period of floral initiation. Heavy shading up to complete darkening consistently reduced the number and size of inflorescence primordia. This reduced fruitfulness could not be related to changes in the spectral quality of the light, which might have upset the phytochrome system, nor to changes in temperature of the buds.