Resumo

PIRE, Reinaldo; PEREIRA, Aracelys; DIEZ, Julio  e  FERERES, Elías. Drought tolerance assessment of a venzuelan grape rootstock and possible conditioning mechanisms. Agrociencia [online]. 2007, vol.41, n.4, pp.435-446. ISSN 2521-9766.

Tolerant rootstock is used to confer plants the capacity of adaptation to drought conditions. Criolla Negra rootstock is used in viticulture in Venezuela, but there is no information available that indicates whether it possesses or can confer drought tolerance. The objective of this study was to compare vegetative growth of the rootstock with Chenin blanc and Syrah grape varieties, grown on their own roots or grafted onto the rootstock and subjected to different levels of water deficit. The five resulting combinations of plant material were distributed in three irrigation treatments (abundant, moderate and deficient) in a completely randomized design with a factorial arrangement and 12 replications. Water deficit reduced leaf water potential in all of the materials and, at the same time, produced a slight decrease in the mass of the root system and a greater reduction of the shoot (p≤0.05), in the mass of shoots and in leaf area. The root mass of the rootstock markedly surpassed (p≤0.05) that of the varieties, regardless of whether they were grafted or grown on their own roots. Under conditions of abundant irrigation, the varieties Chenin blanc and Syrah grafted on Criolla Negra showed small, but significant, differences in growth relative to the same varieties cultivated on their own roots. Some characteristics of the rootstock that made it possible to classify it as vigorous and able to confer drought tolerance were an extensive root system (double that of the other materials in moist soil and triple under drought conditions) and greater water use efficiency under drought conditions.

Palavras-chave : Vitis vinifera; water use efficiency; water stress; water relationships; irrigation.

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