Dry matter accumulation and partitioning of Cabernet Sauvignon pot-grown vines underdifferent water regimes

Vegetative growth, gas exchange, yield and berry characteristics of Cabernet Sauvignon vines (Vitis vinifera L.) grafted on Kober 5BB and grown in pots under different soil water regimes were studied. Vines were trained on Guyot system (cane pruning 0.30 m above the ground) and were grown in 45-liter-pots containing an equal loam, sand and peat mix (1:1:1 in volume) and irrigated by drippers. Three different water regimes were imposed: 100%, 50% and 25% of transpiration water evaluated each ninth day by pot weight. Each third day, vine water losses by plant transpiration were fully re-intregrated for the 100% treatment, whereas it was one-half and one-fourth of transpiration water for 50% and 25% treatments respectively. The aim of this work was to investigate the effect of water regime on vegetative and reproductive growth and carbon partitioning in young container-grown vines. Both vegetative growth and gas exchange were affected by vine water status. Vine total dry matter resulted proportionally related to the water regime, the values obtained for the three treatments being significantly different. Results showed that water regime may affect yield per vine and berry size, according to previous studies. The analysis of berry composition pointed out the enhanced sugar accumulation in the case of full reintegration of transpiration water (100% treatment). The organic acid component was also proportionally increased as the soil water content was higher. The components of fruit quality were directly affected by vine water status.