EFFECTS OF LIGHT REDUCTION AT BLOOM ON FRUITS SET IN BLACK MAGIC TABLE GRAPES CV IN EARLY AND LATE PRODUCTION CICLES

A shading experiment in ‘Black Magic’ cv was conducted in Sicily to test a new thinning method, aiming to reduce the no. berries/cluster, maximising quality and value of the production. A reduction of intercepted light was imposed at the 65 stage of the BBCH scale (50% cap fall) for 12 days. The soilless greenhouse conditions allowed two growing cycles occurring under different climate conditions, an early (end of March flowering) and a late production cycle (beginning of August flowering). During the shade treatment, net photosynthetic rate was significantly reduced by 82% and 96% in the late and early production cycles, respectively. The sum of flowers and berries dropped in the untreated…