@article {78, editor = {,}, title = {Influence of Artificial Shading of Vineyards on the Concentration of Sugar and Organic Acid in Grapes}, volume = {18}, number = {2}, pages = {78--86}, year = {1967}, doi = {10.5344/ajev.1967.18.2.78}, publisher = {American Journal of Enology and Viticulture}, abstract = {Vines of Vitis vinifera L., varieties {\textquoteleft}Pinot noir{\textquoteright} {\textquoteleft}White Riesling{\textquoteright}, and {\textquoteleft}Sauvignon blanc{\textquoteright}, were covered from approximately mid-July to mid-September with one of two types of plastic Saran shade material which reduced the total solar radiation to either 30 or 21\% of full sunlight.Reduced light delayed fruit maturation 1 to 5 weeks. The total accumulated calories of solar and sky radiation required for the maturation of fruits from {\textquoteleft}White Riesling{\textquoteright} and {\textquoteleft}Sauvignon blanc{\textquoteright} vines grown under 30\% sun averaged 16\% and 20\% less, respectively, than the energy required for the maturation of grapes grown in full sunlight. Total acidity and concentration of malates in mature {\textquoteleft}Sauvignon blanc{\textquoteright} fruits grown under 30\% sun were approximately 20 and 13\% greater, respectively, than in fruits of similar maturity from vines grown under full sun. The concentration of tartrate of 21 and 30\% sun fruits were nearly equal, whereas the concentration of malate was slightly higher in the 21\% sun fruits. The average fresh weights of berries from 30\% and from 100\% sun vines were approximately the same; however, average fresh weight of berries was usually slightly less for 21\% sun vines than for vines receiving higher light intensities. The maturation and composition of {\textquoteleft}Sauvignon blanc{\textquoteright} fruits from vines covered 2 weeks before v{\'e}rasion were not significantly different from fruits of vines covered at v{\'e}rasion.}, issn = {0002-9254}, URL = {https://www.ajevonline.org/content/18/2/78}, eprint = {https://www.ajevonline.org/content/18/2/78.full.pdf}, journal = {American Journal of Enology and Viticulture} }