Transparent polyethylene covering film in tropical grapevines does not alter photosynthesis, plant growth, fruit quality or yield

Information concerning the effects of the transparent plastic covering (TPC) on photosynthetic performance, plant growth and yield of tropically grown grapevines is limited. Thus, this study aimed to evaluate the effects of TPC on leaf gas exchanges, photochemical efficiency, plant growth and both fruit quality and yield in Vitis labrusca cv. ‘Niagara Rosada’ and V. vinifera cv. ‘BRS Clara’. The research was conducted from September (spring) to December (summer) 2012 (Harvest 1—H1) and from March (autumn) to June (winter) 2013 (Harvest 2—H2). Both genotypes were grown in either covered (TPC: low-density polyethylene—LDPE) or uncovered (NTPC: control) sites. Leaf gas exchanges, chlorophyll a fluorescence and leaf water potential, plant growth as well as fruit yield and quality were measured. We found that modifications of microclimatic variables caused by TPC use [i.e., increases in air temperature (+ 8% at H1 and + 6% at H2 in Tmax), in temperature amplitude (ΔT °C—+ 17% at H1 and + 7% at H2), and in VPDairmax (+ 25% at H1 and + 20% on H2), as well as reductions in photosynthetic photon flux density (PPFD, − 28% at H1 and − 45% at H2)] did not substantially affect leaf gas exchanges, photochemical efficiency, plant growth and both fruit quality and yield of both genotypes. Therefore, the greatest benefits of growing table grapes in tropical regions under TPC can be associated with grape protection.