Effects of different plastic sheet coverings on microclimate and berry ripening of table grape cv 'Matilde'

Two types of plastic cover (LDPE + EVA and LDPE + HDPE) were tested to assess their radiometric properties and the influence on the vegetative and reproductive performances of ‘Matilde’ table grape. Films showed the same transmittance to short infrared waves, but LDPE + EVA had a higher transmissivity to visible, PAR and short infrared wavelength ranges of solar radiation, especially as for the ‘direct’ light component. In comparison to the open field, covering increased GDD accumulation and advanced budbreak by 12 days (LDPE + HDPE) or 20 days (LDPE + EVA). Commercial ripening (14 °Brix) was advanced by 8 and 22 days, respectively. Must acidity was higher in open field than under LDPE + EVA. Yield per vine increased under LDPE + EVA, although not at a significant level; bunch mass was higher under LDPE + EVA than in open field. Berry mass was maximum under LDPE + EVA and progressively decreased under LDPE + HDPE and in open field. Under covering, the pruning cane mass increased by 63 % with LDPE + EVA and 43 % with LDPE + HDPE