Comportamento vegetativo e produtivo de videiras 'Cabernet sauvignon' cultivadas sob cobertura plástica

there is an increasing adoption of overhead plastic covering for grapevines in the state of rio grande do sul, southern brazil, to protect the plants from rain and hail storms. this study was carried out to evaluate the impacts of overhead plastic covering with a translucent and water-proof plastic film on phenological, growth (of branch, leaves, clusters, and berries), and yield attributes of five years old 'cabernet sauvignon' grapevines (vitis vinifera l.) on paulsen 1103 rootstock raised as 'y' management system. the experiment was carried out in caxias do sul, state of rio grande do sul, and followed a randomized block design, with two treatments (uncovered and covered plants) and four replicates of 15 plants (experimental unit). the micro-environmental changes imposed by the cover did not affect grapevines phenology. the grapevines under the cover had higher values for branches growth (length and fresh mass), and leaf expansion (area and dry mass) than the uncovered ones. the berries weight and diameter were superior on grapevines under covering plastic only at earlier stages of fruit growth but not at harvest. the other variables assessed were not affected by the cover. the results show that overhead plastic covering can interfere with vegetative growth without affecting yield.