Blossom-end Rot of Tomato Fruit as Influenced by Osmotic Potential and Phosphorous Concentrations of Nutrient Solution Media1

Abstract

Abstract Tomato plants (Lycopersicon esculentum Mill.) were grown to maturity in complete nutrient solution with osmotic potentials (sψo) of −0.8, −2.4, −4.4 and −6.4 bars from NaCl additions, and 0.5, 5.0, and 50 ppm P as variables. The objectives were to evaluate the effects of sψo and P and their interactions with respect to fruit yield and quality, and nutrient concentrations in the plants and fruits. Reducing the sψo (increasing negative values) by NaCl addition significantly decreased tomato fruit yield, but increased the percentages of soluble solids, total solids, blossom-end rot (BER) incidence and non-marketable fruit. Increased solution salinity resulted in higher leaf concentrations of P, Na and Cl. Increased nutrient solution P levels (Ps) significantly increased fruit yield, but decreased the percentage of fruit soluble solids and BER incidence. Leaf P, Ca and Cl concentrations of plants grown in the high P nutrient solution were higher than those of the leaves from low P solution plants. The incidence of BER was greatest under low sψo and low Ps. Reduced Ca concentrations of leaves and mature fruit were associated with the BER development. The Ca concentration of mature normal fruit varied from 0.039 to 0.076% compared with 0.028 to 0.043% for mature BER fruit. Leaf Ca concentrations of 1.5 to 2.0% were associated with the BER condition.