Influence of leaf canopy height on the occurrence of berry shrivel

Abstract

Berry shrivel (BS) is a physiological disorder of grapevine that causes severe grape quality losses. The origin of BS is still unknown. In a trial with different treatments of the leaf canopy, a higher BS incidence in the plots with reduced leaf area was observed. Therefore it was investigated, whether a strong reduction of the canopy height regularly promotes BS development. Further, berry and leaf analyses should give evidence of possible changes in mineral contents which could be related to BS incidence. In three out of four trials, a strong reduction in leaf canopy height at the beginning of berry ripening, resulted in the appearance of berry shrivel (BS) symptoms. Intensive shoot topping during berry ripening therefore strongly increases the likelihood of BS occurrence, but does not always result in the appearance of BS symptoms. At the end of the berry ripening period, leaves in the reduced canopy height treatment (RCH) showed higher nitrogen content and lower potassium content than those in the normal canopy height treatment (NCH), suggesting a high and maybe also passive absorption of nitrogen, which hinders the absorption of potassium. These findings open new approaches for further studies on the causes of BS.