Bar-Tal, A., Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel, Institute of Soils and Water, Israel
Pressman, E., Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel, Institute of Field and Garden Crops, Israel

Root restriction has been reported to reduce fruit yield, the incidence of blossom end rot (BER) and K concentration in tomato (Lycopersicon esculentum L. 'F121') plant organs. The objectives of the present work were to study the effect of root restriction, and combination of K and Ca solution concentrations, on greenhouse tomato fruit yield, quality and cation uptake. Root restriction reduced total yield but improved fruit quality by increasing the dry matter concentration and reducing the incidence of BER. Increasing the K concentration from 5.0 to 10 mmol · L - 1 reduced the marketable yield, due to increased incidence of BER. Root restriction decreased K concentration and K/Ca ratio in tomato plant organs, but had no effect on K uptake rate per unit root fresh weight. Increasing K concentration from 2.5 to 10 mmol. L -1 increased the K concentration in plant organs and K uptake rate, but reduced that of Ca. In contrast, increasing Ca concentration in the solution had no effect on K concentration in plant organs and K uptake rate. The incidence of BER correlated well with K/Ca concentration ratio in the leaves, whereas a poor correlation was obtained with K/Ca concentration ratio in ripe fruit.