Bar-Tal, A., Institute of Soils and Water, ARO, Volcani Center, POB 6, Bet Dagan, 50-250, Israel
Rylski, I., Institute of Field and Garden Crops, ARO, Volcani Center, POB 6, Bet Dagan, 50-250, Israel
Feigin, A., Institute of Soils and Water, ARO, Volcani Center, POB 6, Bet Dagan, 50-250, Israel
Pressman, E., Institute of Field and Garden Crops, ARO, Volcani Center, POB 6, Bet Dagan, 50-250, Israel

Fruit quality is a crucial factor in the production of greenhouse tomatoes. Impaired fruit quality such as smaller fruit in the upper trusses, blotchy ripening and blossom end rot (BER) are common tomato fruit disorders in Israel. The objective of this study was to improve fruit quality of greenhouse tomato by agrotechnical methods; root pruning and restriction in combination with variations of N-NO3, K and Ca solution concentrations, and fruit thinning. Although root pruning reduced shoot growth, fruit yield, and average fruit weight, it increased the percentage of fruits free of internal and external blotchy ripening. Root restriction increased total soluble sugars (TSS) in the fruit and decreased the percentage of fruit affected by BER. Increasing the nutrient solution concentration of K from 2.5 to 10 mM increased the occurrence of BER, whereas increasing Ca concentration from 3 to 7 mM reduced it. Root restriction decreased K concentration in the leaves and fruit. Increasing NO3 solution concentration from 1 to 9 mM did not compensate for the pruned or restricted roots reduction sin tomato yield, alter either TSS content or the occurrence of blotchy ripening, but did increase the incidence of BER. Thinning to four fruits per truss reduced fruit yield by 40%, but increased the average fruit weight of the trusses above the fourth truss by 50%.