Effect of pre-bloom anti-transpirant treatments and leaf removal on Sangiovese (Vitis vinifera L.) winegrapes

Recent trials have shown that basal shoot leaf removal at pre-bloom is effective in reducing fruit-set and yield, leading to better grape quality composition. The present trial was designed to determine whether similar results can be achieved with Sangiovese vines by testing a pre-bloom spray of film-forming anti-transpirant (P) against pre-bloom hand defoliation of basal leaves of shoots (HD) and no defoliation (C). In a three year experiment (2008-2010) the results were as follows: compared to C, the P reduced the net assimilation of treated leaves for 20-40 days and photosynthetic compensation was not found after treatments in the upper not treated leaves of P and in the remaining upper HD leaves; berry-set, cluster weight and yield were significantly reduced in P and HD compared to C; bunch compactness decreased in HD compared to C, with P clusters registering an intermediate value; must soluble solids content (Brix) and pH of P and HD were increased compared to C, while no differences were found among treatments for titratable acidity; berry weight was also not affected by the treatments and skin weight and anthocyanins content of P and C berries was similar, while HD berries, fully exposed to ambient light and temperature throughout the seasons, showed higher skin weight and skin weight-to-berry weight ratio, but a decreasing of total skin anthocyanins content compared to C and P.