Grapevine cultured in trenches: root growth and dry matter partitioning

As a part of a global project aimed at comparing the physiology of several grapevine (Vitis vinifera L.) cultivars, we tested plant cultivation in tre nches under semi-controlled conditions. Vegetative growth of vines of two c ultivars, Pinot Noir and Merlot, from different locations, were followed du ring a 3-year period. Roots of trench-grown vines grew widely, leading to a root architecture closer to that observed under field conditions than that of potted vines. In addition, the root system could be sampled exhaustivel y for analyses. Although morphologically different, vines of the two cultiv ars exhibited similar patterns in dry matter production during the whole pe riod, except at early flowering in year 3. Surprisingly, perennial parts ac counted for this difference, though both cultivars were grafted onto the sa me SO4 rootstock clone. Consistently, vines exhibited root necrosis at any sampling date throughout spring, this process affecting more roots for the Pinot Noir/SO4 combination than for Merlot/SO4.