Effects of rootstock and environment on the behaviour of autochthone grapevine varieties in the Douro region

In an experiment located at Quinta da Cavadinha, Sabrosa, Douro Region the behaviour of the varieties Touriga Nacional (TN), Tinta Barroca (TB), Touriga Franca (TF) and Tinta Roriz (TR), grafted onto the rootstocks Rupestris du Lot, R110, R99, 1103P and 196-17, was accessed over 11 years between 2001 and 2011. The main results point to a significant influence of the environmental conditions in different years, especially those providing reduced water availability and greater heat stress: 2004, 2005, and 2009. Crop yields followed the sequence TR, TF, TB>TN, with highest oenological aptitude for TN and climate adaptive capacity to the TF. In terms of the rootstocks we confirm the lower production induced by R. Lot compared with R99, whilst 196-17 offered a good compromise between yield and quality for a great amplitude of climate conditions.