Effect of water stress on dry matter accumulation and partitioning in pot-grown olive trees (cv Leccino and Racioppella)

•Significant changes in the distribution of dry matter were highlighted.•The canopy/root ratio and yield was reduced less in the cv Racioppella.•Cv Leccino obtain higher dry matter accumulation with optimal level of water.•Cv Racioppella showed a more balanced ratio between parts below and above ground.•Cv Racioppella proved more resistant in conditions of water deficit.

Three different water regimes were applied on young pot-grown olive trees of the cultivars Leccino and Racioppella, amounting to 100% (treatment T100), 50% (treatment T50) and 25% (treatment T25) of water transpiration as determined by pot weight. During the two-year trial the following parameters were measured: midday stem water potential, shoots growth, total leaf area per tree, dry matter accumulation and partitioning in different parts of the plant (root, wood, leaves and fruits). Dry matter was affected by the water regime and cultivar. The cv Leccino, for T100, displayed a greater accumulation of total dry matter and fruit dry matter, while these two parameters were greatly reduced under the other water regimes (T50 and T25). By contrast, the cv Racioppella always showed a lower accumulation of dry matter and a more balanced canopy/root ratio.